John Abelson, University of Illinois-Urbana
Laura Espinal, National Institute of Standards and Technology
Claes-Goran Granqvist, Uppsala University
Enrico Traversa, King Abdullah University of Science and Technology
Symposium Support NISE Network
Sustainable Materials and Technologies
FF3: Sustainability Challenges and Approaches
Monday PM, December 01, 2014
Hynes, Level 2, Room 203
2:30 AM - *FF3.01
A Chemistry Perspective on Materials Sustainability
D. Constable 1
1ACS Green Chemistry Institute Washington USAShow Abstract
Without a doubt, industry has created an amazing variety of molecules and materials that go into the products that are a large part of our modern way of life. For a majority of the chemicals and compounds outside of the pharmaceutical industry, we have a limited amount of information upon which to make reasonable decisions about their toxicity to humans or the environment, their degradability (biological or otherwise), our ability to recycle or reuse them, or their renewability.
Society is heavily dependent on the products of the chemical industry; however, most of us know very little about where the basic building blocks come from, at what social and environmental cost, and if there are any elements facing critical supply constraints. For many elements that are of critical importance, like those used in catalysis, electronics and energy production, we are taking a large amount of mass, concentrating the desired elements and dispersing these same elements into a form that is sometimes difficult to recover and reuse.
This talk will set the context for the problem, discuss several compelling examples where key material life cycles need to be closed, and discuss a way forward.
3:00 AM - FF3.02
Human Health Considerations as an Integral Component of Sustainable Materials Design: Industry Change and New Research Opportunities
Ashley A. White 1
1U.S. Green Building Council San Francisco USAShow Abstract
Energy, water use, and environmental impacts are among the first topics that researchers consider in sustainable materials development. However, minimizing the negative human health impacts of materials and their production processes is just as critical to ensuring the safety of current and future generations.
Spurred by recent industry actions, such as internal retailer policies (e.g. chemical "red lists") and green building rating systems like Leadership in Energy and Environmental Design (LEED) that are incorporating more stringent requirements around materials impacts, manufacturers are increasingly expected to account for both the environmental and human health aspects of their products. Because of this, they are looking for ways to redesign or reformulate their products to meet the needs of the changing marketplace. In some cases, manufacturers have difficulty finding substitutions for chemical and material ingredients deemed unsuitable due to their negative effects.
This situation presents both new considerations for researchers creating novel materials destined for the marketplace, as well as new opportunities for research into safer material chemistries and processing methods.
This talk will make a case for human health considerations being an integral, yet oft-overlooked, component of sustainable materials development. It will highlight important governmental policies and regulations in this arena, recent industry actions impacting environmental and human health considerations of materials, and present new opportunities for research.
3:15 AM - FF3.03
Tools for Sustainable Development of Impoverished Areas
Jameson Wetmore 1 2
1Arizona State University Tempe USA2Arizona State University Tempe USAShow Abstract
There has been a recent move by scientists and engineers in the United States to tailor some of their work for developing countries and areas. The idea is that engineering can help to meet some of the basic needs of impoverished people, raise their standard of living, and create more sustainable communities. Past projects have included attempts to provide off-the-grid energy, clean water, and wastewater treatment and/or disposal. The interest in this topic can be seen in the variety of efforts to outline engineering strategies for the Millennium Development Goals and the fact that it is increasingly difficult to find a major university that does not have an active Engineers without Borders program.
Unfortunately the history of the modern world&’s attempts to address impoverished areas through technology transfer is riddled with failures. Sometimes the technologies sit unused weeks after they are introduced. Sometimes the technologies disrupt the social fabric of the community. Problems like these arise not because the motives of the engineers were necessarily bad, but because their training is mainly in technical areas and only a small part of the overall problem is technical in nature. There are rare occasions when technologies mesh with the infrastructure, social frameworks, and needs of the community to enable positive lasting change. These successes come only when the designers involved understand the people they are working with. And even then a fair amount of luck is needed.
This presentation will cover the basic lessons developed for a training program designed to help engineers and scientists interested in addressing the problems of t\he developing world. The two day workshop has already been held at Georgia Tech and the University of the Western Cape in South Africa and by the time of the fall MRS meeting it will have been held at Concordia in Montreal as well as Arizona State University. The workshop does not give participants everything they need to know to be able to engage in development work, but helps them to avoid some of the common pitfalls that doom many projects at the earliest stages.
Most significantly the workshop focuses on the importance of working to understand the relationship between technology, people, and the environment and provides tools to begin to learn more about their interactions. It argues that the key to any successful project is successful engagement. Outsiders will never be able to understand the context of the situation well enough to create a successful design. Opening up ways of communicating with the community are crucial even as early as the first step of defining what problem might be useful addressed. The workshop illustrates the dangers of not listening and provides techniques for engineers and scientists to better listen to the people they want to help and observe the environment in which they will work.
3:30 AM - FF3.04
Organic Polymer Light-Emitting Diodes: An Economic, Environmental, and Efficiency Assessment
Catrice M Carter 2 Xiaojun Wang 1 3 Sivarampragadeesh Siva 2 Deirdre O'Carroll 2 3
1Jilin University Nanguan, Changchun, Jilin China2Rutgers University Piscataway USA3Rutgers University Piscataway USAShow Abstract
Proponents for sustainable alternative lighting and display options advocate for organic light-emitting diodes, particularly polymer light-emitting diodes (PLEDs) whose color range extends the entire visible spectrum, because of their potential low-cost fabrication, low operating voltage, and low power consumption. In this work, a materials life-cycle analysis was completed for three alternative device configurations to the conventional bottom-emitting PLED device structure - inverted bottom-emitting, conventional top-emitting and inverted top-emitting - due to their potential to increase device operational lifetime (inverted) and light out-coupling efficiency (top-emitting). The study was completed in terms of the following metrics: materials cost, projected total life cost savings, life-cycle power cost, and operating energy consumption per unit area. We find that glass, indium tin oxide (ITO), and conjugated polymer active-layer materials are the main contributors to materials cost for the conventional bottom-emitting device, accounting for 70 %, 12 %, and 14 % of the materials cost, respectively. This is a result of the large glass layer thickness (greater than1000 µm) compared to other device layers (less than 142 nm) and the high cost to fabricate both ITO and the active-layer materials. Approaches to increase the total life cost savings are: implementation of device designs that utilize thinner glass substrates that can be re-used following a device lift-off process; elimination of indium tin oxide; and increasing device operating lifetime and efficiency. We will show that the conventional bottom-emitting device has the lowest total life cost savings, approximately 3 times that of its top-emitting counterpart, while the inverted top-emitting device has the lowest life-cycle power cost and operating energy consumption per unit area due to its approximately 1.5 times longer operational lifetime and its factor of 2 reduction in power consumption. In addition, electromagnetic simulations of light extraction efficiency and the percentage of light energy trapped or absorbed in each layer of the devices will be presented and considered alongside the other metrics to select the optimal device architecture in terms of efficiency, cost and environmental factors.
Monday PM, December 01, 2014
Hynes, Level 2, Room 203
4:15 AM - *FF4.01
Materials for Membranes and Water Sustainability
Suzana Nunes 1
1KAUST Thuwal Saudi ArabiaShow Abstract
The availability of drinking water and water reuse for agriculture or industrial purposes has been increasingly facilitated by membrane technology. Well-established processes like reverse osmosis dominates the market for water desalination. Other emerging processes are being implemented with the development of membranes with a diverse set of properties. Examples are nanofiltration for partial desalination of seawater for agriculture, forward osmosis for hybrid water reuse systems, microbial fuel cell and pressure-retarded osmosis for water-energy recovery. Our group has been dedicated to the synthesis of new polymers, their functionalization and morphology control aiming at the application to water-based separations. We focus on the development of porous membranes, which depending on hydrophobicity can be applied membrane distillation (MD) and ultrafiltration, as well as support for multilayer nanofiltration or forward osmosis membranes. We have been working for instance with fluorinated polyoxadiazoles and polytriazoles for MD. Analogous polymers with different chemical functionalizations have been used to manufacture solvent resistant membranes (hollow fiber and flat-sheet) for ultrafiltration and as support for forward osmosis. Besides chemical functionality, morphology control is a challenging task. Most of the available membranes have a broad range of pore size distribution. We have been exploring special techniques based on block copolymers to enable the manufacture of membranes with exceptional high and regular porosity. Recent advances and strategies for membrane manufacture for water-based separations will be summarized.
4:45 AM - FF4.02
Novel Hydrophobic Ionic Liquid Based Polymer for Membrane Pervaporative Enrichment of 1,3 Propanediol from Aqueous Solutions
Baishali Kanjilal 1 Iman Noshadi 2 Richard Parnas 1 2
1University of Connecticut Wilimatic USA2University of Connecticut Storrs USAShow Abstract
A paradigm shift towards renewable fuels like biodiesel comes with the adverse aspect of excess raw glycerol byproduct, fermentation of which to 1,3 propanediol provides a sustainable recourse to waste utilization. However, the downstream enrichment of such polar organics, typically produced in dilute mixtures, constitutes a major process efficiency bottleneck. Although membrane separation processes offer cheap and energy efficient alternatives of upgrading the concentration, high water affinity of 1,3 propanediol compounds the difficulty in pervaporative enrichment prompting the need to develop novel materials. The synthesis of a novel hydrophobic imidazolium ionic liquid salt monomer and its polymerization and copolymerization is presented. The monomer chemically anchors a hydrophobic high boiling solvent via a Menshutkin like pathway. The polymers are characterized by spectroscopy, thermal analysis, thin film water contact angle and mass uptake. A plug membrane is fabricated from these polymers and evaluated for batch pervaporation with a separation factor of ~ 100. These values are bettered only by high boiling hydrophobic cyanoborate ionic liquid based supported liquid membranes. Incorporation of a small molar percentage of Divinyl benzene and butyl acrylate causes a reduction in separation performance but is seen to maintain mechanical integrity for a longer period of time, thus allowing for structural membrane engineering and industrial scale up.
5:00 AM - FF4.03
Theoretical Study of Molecule Separation in Nanoporous Materials for Realization Sustainable Future
Rodion Belosludov 1 Yoshiyuki Kawazoe 2 3
1Institute for Materials Research Sendai Japan2New Industry Hatchery Center, Tohoku University Sendai Japan3Kutateladze Institute of Thermophysics, SB RAS Novosibirsk Russian FederationShow Abstract
Our rapidly developing modern society challenges to scientific and engineering organizations in that many of the currently used technologies and prospective engineering innovations need to be directed in a more sustainable way. Therefore, materials science and sustainable engineering will continue to have important roles in five key thematic areas such as energy, transportation, housing, materials resources and health . In parallel with the experimental efforts, computer-aided materials design is also an important factor in the fabrication of novel materials, to be applied in driving engineering innovations and urgent technological needs for achieving a sustainable society. The recent advent of metal-organic framework materials (MOFs), as new functional adsorbents has attracted the attention due to scientific interest in the creation of unprecedented regular nano-sized spaces and in the finding of novel phenomena, as well as commercial interest in their application for storage and separation. For MOFs the structural versatility of molecular chemistry has allowed the rational design and assembly of materials having novel topologies and exceptional host-guest properties that are important for urgent sustainable applications. Due to the regularity of MOF structures, in a computer simulation we are easily able to build structural models of MOFs that are very helpful to find new materials with desired characteristics.
The aim of this study is detailed theoretical analysis the adsorption of targeted molecules into selected nanoporous materials in order to accelerate the realization of novel materials, hand-in-hand with experiment. Here, our recent achievements have been reported. The high sorption ability for acetylene on specific MOF material was determined , using both different experimental measurements and first-principles calculations which ascribe to the double hydrogen bond support between the acidic acetylene proton and its acceptor basic site on the channel surface. The absorption of several chiral sulfoxides, which constitute an important class of biologically active compounds and therapeutic drugs, into the homochiral porous coordination polymer has been also investigated . In collaboration with experimentalists the specific nanoporous material that selectively adsorbs CO with adaptable pores has been studied using first-principles calculations. The high selectivity of CO has been achieved from a mixture with nitrogen by both the local interaction between CO and accessible open metal sites and the modification of nanopore size .
 D. Apelian, MRS Bulletin2012, 37, 318.
 R. Matsuda et al. Nature 436 (2005) 238.
 D. N. Dybtsev et al. Chem.-Euro. J. 16 (2010) 10348.
 H. Sato et al. Science 343 (2014) 167.
5:15 AM - FF4.04
Fouling Resistant, High Flux Membranes Using Self-Assembling Zwitterionic Copolymers
Prity Bengani 1 Ayse Asatekin 1
1Tufts University Medford USAShow Abstract
Water scarcity affects one in three people globally. Membranes are a key technology for water sustainability, for example wastewater reclamation and reuse. They also use less energy and no added chemicals, which makes their use more “green” compared to distillation and other separation methods. But current commercial membranes are susceptible to fouling, which manifests as a loss in permeability due to macromolecular adhesion on the membrane surface. Fouling lowers productivity and increases energy consumption and cost. We need membrane materials that offer excellent fouling resistance, along with high flux and selectivity. Here we report a new class of membrane materials using self-assembling zwitterion-containing polymers. Zwitterionic groups strongly resist biomacromolecular fouling due to their high affinity with water, which makes them favorable for membrane applications. Zwitterions are known to self-assemble into channel-type clusters of 0.6-2 nm in size. We have shown that within certain composition ranges, random copolymers of zwitterionic and hydrophobic monomers self-assemble to form bicontinuous networks of nanochannels. We have synthesized such copolymers and formed thin film composite membranes by coating them onto commercial ultrafiltration membrane supports. These membranes exhibit permeabilities as high as 21 L/m2.h.bar, which can be further improved by better membrane manufacturing and processing methods. Based on the rejection of anionic dyes of varying sizes, they show size-based selectivity with a size cut-off around 1 nm. This pore size closely matches the size of the zwitterionic nanochannels, measured to be ~1.1-1.4 nm in diameter by transmission electron microscopy (TEM). We have also demonstrated the excellent fouling resistance performance of these membranes in parallel to a commercial membrane of comparable pore size. We expect these membranes to be promising candidates for various membrane and sustainable water applications.
5:30 AM - FF4.05
Investigation of Novel Opuntia Ficus-Indica Mucilage Nanofiber Membrane Filtration for Water Systems
Sylvia W Thomas 1 Norma A. Alcantar 2 Fei Guo 2 Daniela Stebbins 2 Manopriya Devisetty Subramanyam 1 Hrudaychand Katakam 1 Samuel Perez 1 Rasudha Muppaneni 1
1University of South Florida Tampa USA2University Of South Florida Tampa USAShow Abstract
Nanofiltration technology is being investigated as a cost-e#64256;ective and environmentally acceptable mechanism of sustaining industrial and public water systems. Nanofiber membranes are part of the family of filtration devices being used to remove inorganics and organics from water systems. This study investigates the use of the natural material, Opuntia ficus-indica (Ofi) cactus mucilage, as a tool for nanofiber membrane filtration. Mucilage is a natural, non-toxic, bio-compatible, biodegradable, inexpensive and abundant material. Mucilage is a clear colorless substance comprised of proteins, mono-saccharides, and polysaccharides. It also contains organic species which give it the capacity to interact with metals, cations and biological substances promoting flocculation for removing arsenic, bacteria, E. coli, and other particulates from drinking water. This natural material has the potential to be used as a sustainable method for water filtration and contaminant sensing. Therefore, mucilage nanofiber membranes were electrospun with volume ratios of polyvinyl alcohol (PVA) and polystyrene (PS) to mucilage comparing the interaction of non-polar solvents. Atomic Fluorescence Spectrometry (AFS) from PSAnalytical was used to evaluate electrospun nanofiber membranes made from volume ratios ranging from 30:70 to 70:30 of mucilage: polyvinyl alcohol, mucilage: polystyrene-D-limonene, and mucilage: polystyrene-toluene in different proportions. The mucilage nanofiber membranes were used as filtration devices for 50 ppb arsenic solutions. Arsenic, being a toxic substance, acts as a deadly poison in water systems and has plagued societal preservation for centuries. The total arsenic content in the samples were measured before and after treatment. Comparative tests were also performed using 1) coated and non-coated GVWP 0.22 µm and 0.45 µm filters from Millipore and 2) columnar flow through Pasteur glass pipets filled with 0.5 g of pre-washed sand from Fisher Scientific and 0.01 g of mucilage nanofibers. Results show mucilage: polystyrene nanofiber membrane filters were capable of removing arsenic from test solutions, in terms of the percentage of arsenic removed. These data elucidate that mucilage nanofiber membranes have the potential to serve as the basis for the next generation of economically sustainable filtration devices that make use of a natural non-toxic material for sustainable water systems.
FF1: Focus on Sustainability: The Research / Corporate Nexus
Monday AM, December 01, 2014
Hynes, Level 2, Room 203
9:00 AM - *FF1.01
Materials Science for the Anthropocene
Martin Green 1
1NIST Gaithersburg USAShow Abstract
Civilization on our planet took a sharp turn about 250 years ago, at the beginning of the industrial revolution, and has accelerated on that highway ever since. Arguably, its impact on humankind is equivalent to that of the invention of fire. The enormous consequences of industrial activity, positive and negative, could not have been anticipated then, but the bottom line today is that
per capita global consumption of energy is higher than ever, and demand for materials (relative to the year 1900) has increased by factors of 3 to 6000, depending on the element. Total population as well as those segments of the population doing the consuming, is also increasing. Now we speak (informally, thus far) of the Anthropocene, the first geological epoch in which human activity is deemed to have had an effect on the Earth&’s ecosystem. For how much longer can economic growth and demand for goods be sustained, and can the same human ingenuity that started the industrial revolution mitigate its effects?
In this talk I will address the meaning and definition of sustainable development, and explore the space at its intersection with materials science. Every human endeavor should be informed by sustainable development, because none of our material resources are in#64257;nite and only a few sources of energy are sustainable. The most common definition of sustainable development comes from the 1987 Brundtland report, “Our Common Future”, and states that “Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” However, this is not a scientific definition, and essentially refers to economic development. Further, it requires that we know, or at least accurately estimate, what the needs of future generations will be. The immediate and direct connections between sustainable development and materials science include ef#64257;cient use of materials, materials life cycle assessment, replacement materials, energy-related materials, and water puri#64257;cation. I will highlight what MRS as a scientific society has been doing in the field of sustainable development, and suggest what future materials scientists should know about this field. From MRS&’s activities in sustainable development thus far, we have learned that there is nothing we do as humans to ensure our survival (food, water, materials, shelter, economy, health) that lies outside of its boundaries.
9:30 AM - *FF1.02
Materials Research and Sustainability
Mary Galvin 1
1National Science Foundation Arlington USAShow Abstract
The National Science Foundation has a crosscutting initiative, Science, Engineering and Education for Sustainability, which supports research through a portfolio of programs. One of these programs, Sustainable Chemistry, Engineering and Materials (SusChEM), is particularly relevant to the materials community. This talk will provide an overview of sustainability and its significance to society and materials research. Topics covered in SusChEM and other NSF programs will be described in detail. These include, but are not limited to, utilization of earth-abundant elements; materials for food, water and energy sustainability; and designing products and devices for zero-waste.
10:00 AM - *FF1.03
Engaging the Public in Constructive Conversations about the Future of Technology
Jameson Wetmore 1
1Arizona State University Tempe USAShow Abstract
Public outreach is often framed as a process of developing lesson plans with an aim of convincing the public to believe a series of facts and/or accept a specific viewpoint. These one-way patterns of communication, however, frequently fall short in at least two important ways. First, the public has many sources of information so getting the attention of a number of people is difficult. And second, the organizations that put together such programs are missing a major source of information that could help them to achieve their goals. Over the past several years museum professionals with the Nanoscale Informal Science Education Network (NISE Net) and scholars at Arizona State University&’s Center for Nanotechnology in Society have been developing techniques that go beyond this “linear model.” These techniques enable two way conversations in which members of the public learn about scientific achievements in a specific area and then build their own ideas of what they think a better future would like with them. What we have found is that the visitors to science museums in the United States are not only able to participate in constructive conversations, but that they are hungry for them. This talk will outline some of the lessons learned through this partnership and offer suggestions for how they can be implemented in other spheres.
10:30 AM - *FF1.04
Why be Good? The Role of Stakeholder Relations in Corporate Sustainability Practices
Michael Barnett 1
1Rutgers University Newark USAShow Abstract
Corporations are the greatest threat to the sustainability of our planet, and yet also promise to be the most effective means of resolving sustainability challenges. What shapes whether they do harm or do good? In this presentation, I focus on the role of a firm's stakeholders in influencing the firm's behaviors. In particular, I outline the role of firm-stakeholder relations in the business case for corporate social responsiblity, and I discuss several studies I've conducted that shed light on the limits of the business case for conditioning firms to engage in socially responsiblity practices.
FF2: Corporate Social Responsibility Roundtable
Monday AM, December 01, 2014
Hynes, Level 2, Room 203
11:15 AM - FF2
Corporate Social Responsibility Roundtable Show Abstract
John Abelson, University of Illinois-Urbana
Laura Espinal, National Institute of Standards and Technology
Claes-Goran Granqvist, Uppsala University
Enrico Traversa, King Abdullah University of Science and Technology
Symposium Support NISE Network
Sustainable Materials and Technologies
FF6: Hydrogen, Batteries and Fuel Cells - Part I
Tuesday PM, December 02, 2014
Hynes, Level 2, Room 203
2:30 AM - *FF6.01
Low Temperature Fuel Cell Developments for a Sustainable Hydrogen-Based-Economy
Emiliana Fabbri 1 Annett Rabis 1 Alexandra Patru 1 Tobias Binninger 1 Xi Cheng 1 Rhiyaad Mohamed 2 Pieter Levecque 2 Olaf Conrad 2 Ruediger Koetz 1 Thomas Justus Schmidt 1
1Paul Scherrer Institut Villigen Switzerland2HySA/Catalysis Centre of Competence, University of Cape Town Cape Town South AfricaShow Abstract
In the last decades many efforts have been directed towards the development of efficient energy conversion systems using renewable energy resources. In the scenario, particular for automotive applications, the development of low temperature fuel cells plays a critical role towards the development of a sustainable hydrogen-based-economy. Alkaline fuel cells (AFCs) were the first low temperature fuel cells developed in the 1960s and mainly used for space program applications. Afterwards, mostly due to the electrolyte deterioration when in contact with CO2, the interest in these systems has been shelved for many years. In parallel, the higher efficiencies and the advantage of using a polymer electrolyte membrane have driven the main research efforts towards the development of polymer electrolyte fuel cells (PEFCs). The main performance drops in PEFCs are caused by the cathodic electrode where the oxygen reduction reaction (ORR) takes place. For the development of competitive PEFCs the discovery of durable and cost-effective catalysts for the ORR is one of the most urgent requirements. State-of-the-art PEFC cathodes are based on Pt nanoparticles supported on high surface area carbons.1 Despite the relatively good performance as cathode catalyst, Pt-supported on carbon suffers from corrosion stability, particularly due to carbon oxidation. Therefore, a growing interest is raising toward alternative, more stable support materials. In the present contribution alternative oxide-based supports have been investigated2-5 and an insight into Pt/oxide novel catalysts will be presented.
In the last decade the development of alkaline conductive membrane has raised again R&D interest towards AFCs. Compared to PEFCs, AFCs make use of an electrolyte medium which is less corrosive with respect to a wider range of compounds, thus significantly broadening the range of possible stable and inexpensive electrode materials. Due to the above mentioned reasons, a broad range of materials has been investigated in recent years as alternative catalysts to noble metals. Particularly, perovskite oxides have shown the potentials of high electrocatalytic activity towards ORR in alkaline media. In this contribution the performance of different perovskites as ORR catalysts will be presented, unraveling the oxygen reduction mechanism for this novel class of materials.6,7
The authors gratefully acknowledge: Swiss National Science Foundation (Ambizione Program), Swiss Competence Center for Energy Research (SCCER) Heat & Electricity Storage, and Umicore GmbH.
 E. Fabbri et al. ChemCatChem 6 (2014)1410-1418.
 A. Rabis et al. Phys. Chem.C 118 (2014) 11292-11302.
 E. Fabbri et al. Phys.Chem.Chem.Phys. (2014) DOI:10.1039/C4CP00238E.
 E. Fabbri et al. Chimia 68 (2014) 217-220.
 T. Binninger et al. J. Electrochem. Soc. 161 (2014) H121-H128.
 E. Fabbri et al. ChemElectroChem 1 (2014) 338-342.
 E. Fabbri et al. ACS Catalysis 4 (2014) 1061-1070.
3:00 AM - FF6.02
Sustainability Assessment of Energy Storage in Hydrogen Using Regenerative Fuel Cells
Matthew A. Pellow 1 Christopher J.M. Emmott 2 3 Charles J. Barnhart 1 Sally M. Benson 1 4 5
1Stanford University Stanford USA2Imperial College London London United Kingdom3Imperial College London London United Kingdom4Stanford University Stanford USA5Stanford University Stanford USAShow Abstract
Sustainable electricity generation technologies are highly variable, and energy storage has an important role in integrating them into the grid at large scale. Building this energy storage capacity has an energy cost, as with any manufacturing process. However, different energy storage technologies have different energy costs for manufacturing the same kilowatt-hour of storage capacity. Net energy analysis, a type of life cycle analysis, systematically examines the life-cycle energy costs of technologies such as energy storage. In this work, we apply net energy analysis to evaluate a regenerative hydrogen fuel cell (RHFC) as an energy storage system. To compare RHFC's to other storage technologies, we use the energy stored on invested (ESOI) ratio: the ratio of energy stored in the device over its lifetime to the energy required to build and operate the device. A device with a higher ESOI ratio provides the same service while consuming less energy during manufacture and operation, leaving the difference available for other productive uses. We present a model to determine the ESOI ratio of a RHFC system as a function of system properties such as storage capacity and fuel cell efficiency.
The ESOI ratio of our hypothetical RHFC system is similar to that of the best battery technology (Li-ion, ESOI = 10; Energy Env. Sci., 2013, 6, 1083), though still lower than those of pumped hydro (ESOI = 240) and compressed air (ESOI = 210). A sensitivity analysis highlights priorities for catalysis research in order to optimize the system's net energy performance: The most important technology advance for increasing the system's ESOI ratio is increasing the fuel cell lifetime to at least 20,000 h, and the electrolyzer lifetime to at least 50,000 h. In contrast, the ESOI ratio is only modestly sensitive to the efficiency of the electrolyzer and fuel cell, and to the embodied energy requirements for manufacturing these components. The system's energy-to-power ratio is also an important parameter. Although there is substantial uncertainty in the embodied energy values, uncertainty analysis indicates that on a net energy basis, a RHFC system can be competitive with Li-ion batteries even with higher-than-estimated embodied energy values. Finally, we illustrate the opportunities for further technology development to improve the net energy balance of RHFC's. For instance, in an RHFC system with an extended-life fuel cell (50,000 h) and electrolyzer (150,000 h) and an energy-to-power ratio of 10, the ESOI ratio would approach 80, well above that of any battery technology.
3:15 AM - FF6.03
Sol-Gel Synthesis of Monodispersed Core-Shell Ferrite Nanoparticles for H2 Generation from Thermochemical Water-Splitting
Vinod Amar 1 Jan Puszynski 2 Rajesh V Shende 1
1South Dakota School of Mines and Technology Rapid City USA2South Dakota School of Mines and Technology Rapid City USAShow Abstract
Core-shell ferrite materials can be utilized for thermochemical water-splitting process to achieve relatively stable hydrogen volume generation in multiple thermochemical cycles. Sol-gel derived ferrite nanoparticles can be further utilized for the preparation of core-shell nanoparticle morphologies. During sol-gel synthesis of core-shell morphology achieving monodispersion of ferrite nanoparticles pose significant technical challenge. As ferrite nanoparticles are magnetic by nature, while preparing the dispersion their agglomeration is unavoidable. To address this issue, we attempted to prepare monoparticulate dispersion of ferrite (e.g. NiFe2O4) nanoparticles, which were later subjected to in-situ zirconia coating following the sol-gel chemistries. Monoparticulate dispersion of ferrite nanoparticles were investigated in presence of non-ionic and ionic surfactants such as Pluronic P123, sodium dodecyl sulfate (SDS) and cetyltriammonium bromide (CTAB) whereas the effects of these surfactants on particle morphology were studied during controlled hydrolysis and condensation reactions of zirconium isopropoxide with water. The obtained ferrite/zirconia gels were aged and calcined at 600oC. Transmission electron microscopy (TEM) revealed core-shell nanoparticle morphology whereas x-ray diffraction showed desired phase composition. These core-shell nanoparticles were loaded inside Inconel tubular reactor where multiple water-splitting and regeneration steps were performed at 900o-1100oC. These results indicated relatively stable H2 volume generation during 10 consecutive thermochemical cycles. The thickness and porosity of ZrO2 shell was found to depend on the type of surfactant used and optimum concentration of the surfactant and reactants employed. H2 volume generation ability of the monoparticulate core-shell ferrite nanoparticles was further correlated with the thickness and porosity of ZrO2 shell. Specific surface area (SSA) and porosity of core-shell nanoparticles were analyzed by BET surface area analyzer whereas grain growth was characterized by scanning electron microscopy (SEM) and TEM after thermochemical water-splitting reaction. Characterization of core-shell nanoparticles and the results obtained on H2 volume generation with core-shell ferrite nanoparticles will be presented.
3:30 AM - *FF6.04
Sustainable Hydrogen Production with Disorder-Engineered Oxide Materials
S. Mao 1
1University of California at Berkeley Berkeley USAShow Abstract
This talk will provide an overview of recent progress in the development of sustainable photocatalytic materials for solar-driven production of hydrogen from water. The emphasis will be recent realization of disorder-engineered titanium dioxide, starting with an introduction of the electronic band structure resulted from disorder incorporation. The method of making disorder-engineered titanium dioxide nanocrystals will be presented, followed by measurements of their structural, electronic, and optical properties. Photocatalysis experiments based on solar-driven hydrogen production using disorder-engineered titanium dioxide nanocrystals, that can absorb solar energy in both visible and infrared wavelength regions, will be summarized, followed by an analysis of the fundamental physics underlying increased photocatalytic efficiency of disorder-engineered titanium dioxide nanocrystals.
FF7: Hydrogen, Batteries and Fuel Cells - Part II
Tuesday PM, December 02, 2014
Hynes, Level 2, Room 203
4:30 AM - *FF7.01
New Materials to Accelerate the Commercialization of Redox Flow Batteries
Mike L. Perry 1
1United Technologies Research Center Glastonbury USAShow Abstract
A Redox Flow Battery (RFB) possesses several key advantages that make this technology potentially well suited for large scale energy-storage applications. This is especially true of applications that require high energy-to-power requirements (i.e., multiple-hour discharge times at rated power) since the energy capacity can be increased by simply adding reactant solution without necessarily requiring (or negatively impacting) the power-delivery components. Despite this inherent scaling-factor advantage relative to conventional battery systems, the initial capital cost of flow batteries has been the major barrier to commercialization of RFB technology. Capital-cost targets for grid-scale energy storage are challenging; battery systems for major grid-scale applications must cost less ($/kWh) than those currently used for most portable or transportation applications. One attractive path to cost reduction is the development of RFB cells with substantially higher power densities than conventional RFB cells. United Technologies Research Center (UTRC) has developed and demonstrated high performance flow-battery cell stacks operating in complete Prototype RFB Systems. A summary of these results has been presented previously. Therefore, the focus of this talk will be on new materials that can potentially enable additional RFB-system cost reductions. This includes both advanced cell materials (e.g., electrodes, separators/membranes, bipolar plates) that can further improve the performance RFB cells, as well advanced reactant solutions. Key system-performance indices provide the basis for the formulation of key property requirements for these advanced materials. A brief review of the state-of-the-art of each these major materials will be included, along with their key properties. The major goal of this presentation is to help material developers identify potential opportunities to substantially improve RFB technology.
The author would like to thank his multiple colleagues at UTRC who have been an essential part of UTRC&’s advanced flow-battery team.
5:00 AM - FF7.02
The Reaction Mechanism of Sn2Fe Anode Materials for Lithium-Ion Batteries
Zhixin Dong 1 Ruibo Zhang 1 Qi Wang 1 Natasha A. Chernova 1 M. Stanley Whittingham 1
1SUNY at Binghamton Binghamton USAShow Abstract
Sn2Fe has been regarded as a promising candidate to replace presently dominating graphite anodes due to its low cost, environmental benignity and high theoretical capacity (804 mAh/g)1. However, the electrochemical reaction mechanism of Sn2Fe is not fully elucidated yet. It has been widely reported that Li-Sn alloys could be formed during lithiation of Sn2Fe while Fe being extruded, whereas Fe is difficult to be detected2,3. But there is a debate for the delithiation process, during which some researchers claimed that the “liberated” Fe particles would remain inert so that Sn2Fe could not be re-created4, while others argued contrarily that Sn2Fe could be reproduced upon delithiation2. To have a comprehensive understanding of the reaction mechanism of this material, pure Sn2Fe was prepared solvothermally by reducing SnCl2 and FeCl3 with NaBH4; the reaction mechanism during the first two cycles has been thoroughly investigated through a variety of in-situ and ex-situ characterization techniques such as X-ray absorption spectroscopy (XAS), powder X-ray diffraction (XRD), pair-distribution function (PDF) analysis, etc. Our results confirmed that the Li-Sn alloys were formed during the lithiation process, so was the Fe phase; such a reaction is reversible upon delithiation and most of Sn2Fe could be re-formed (but with a small portion of discrete Fe and Li-Sn alloys being inactive). During this reaction, the formation and dissolution of Fe were successfully identified by a combined analysis of synchrotron-based XRD, XAS and PDF techniques. This research is supported by DOE-EERE-BATT, DE-AC02-05CH11231 under Award Number 6807148, and by NYSERDA.
(1) Zhang, R.; Upreti, S.; Stanley Whittingham, M. Journal of The Electrochemical Society2011, 158, A1498.
(2) Yoon, S.; Lee, J.-M.; Kim, H.; Im, D.; Doo, S.-G.; Sohn, H.-J. Electrochimica Acta2009, 54, 2699.
(3) Chamas, M.; Sougrati, M.-T.; Reibel, C.; Lippens, P.-E. Chemistry of Materials2013, 25, 2410.
(4) Nwokeke, U. G.; Alcántara, R.; Tirado, J. L.; Stoyanova, R.; Yoncheva, M.; Zhecheva, E. Chemistry of Materials2010, 22, 2268.
5:15 AM - *FF7.03
Reducing the Pt Content in Fuel-Cell Electrodes: Reactivity and Stability of Pt/Ceo2 Nanomaterials from First-Principles Modelling
Stefano Fabris 1
1National Research Council and SISSA Trieste ItalyShow Abstract
Platinum-group metals supported and dispersed on highly reducible oxide surfaces are active catalysts for several reactions of industrial interest, including water-gas shift, selective CO oxidation, hydrocarbon reforming, low-temperature hydrogen/methanol oxidation, and oxygen reduction. Due to their high cost, there is an ongoing effort for reducing the amount of precious metal without affecting the device efficiency. In the context of polymer-electrolyte-membrane fuel cell electrodes, ultra-low loading Pt-ceria (CeO2) systems are investigated as potential candidates for meeting the new national and international targets .
Density functional theory calculations are used to rationalise the enhanced reactivity displayed by these Pt-ceria systems and to characterise the active sites of new materials that minimise the Pt load by means of solid solutions. In particular, I will first focus on supported sub-nm Pt clusters and establish the role of cluster morphology in the thermodynamics and kinetics of surface processes relevant for reactivity: cluster mobility, charge transfers at the metal-oxide interface, reverse oxygen spillover, and oxygen vacancy formation [2,3]. I will then present a thermodynamics analysis that predicts the stability of specific Pt2+ and Pt4+ species in realistic reaction conditions, emphasising the key role played by O vacancies, surface steps and solid solutions . The results will be discussed in the context of recent STM images and XPS data. The different reactivity of these sites towards hydrogen and methanol oxidation will be established and rationalised in terms of local electronic and morphological properties.
The calculated results allow for rationalising the available experimental data and identify correlations among the mechanism of reaction, thermodynamic efficiency, and local structure of the active sites, thus shedding light on the origins of the reactivity and stability of novel Pt/CeO2 materials for fuel-cell electrodes.
 A. Bruix et al., Angew. Chem. Int. Ed., in press.
 P. Ghosh, M. Farnesi Camellone, and S. Fabris, J. Phys. Chem. Letters (2013)
 F. R. Negreiros and S. Fabris, submitted (2014)
 M. Farnesi Camellone, F. R. Negreiros, and S. Fabris, submitted (2014)
5:45 AM - FF7.04
Tungsten Oxide PhotoAnodes Deposited by Pulsed Laser Deposition for Water Splitting Devices
Cristian Fabrega 1 Sebastian Murcia 1 Carles Ros 1 Damian Monllor-Satoca 1 Teresa Andreu 1 Joan Ramon Morante 1 2 Maria Hernandez-Alonso 3 German Penelas Perez 3
1IREC Sant Adriad Spain2UB Barcelona Spain3Ctra de Extremadura Mamp;#243;stoles SpainShow Abstract
Tungsten Oxide is still considered a promising candidate as photoanode for both, water splitting and CO2 reduction. However, photocurrent densities obtained up to now are far away from the theoretical values according to its band gap (2.7 eV). The short diffusion length of the charge carriers limits the thickness of the WO3 films and consequently its light absorbance. In this work, we present high crystal quality WO3 films deposited by Pulse Laser Deposition (PLD) which reduces bulk recombinations through grain boundaries and increase diffusion lengths. Finally, a Al2O3 surface passivation was applied using Atomic Layer Deposition in order to diminish recombination at surface states and also the formation of peroxo-species.
FF8: Poster Session I: Gas Conversion, Storage, Separations
Tuesday PM, December 02, 2014
Hynes, Level 1, Hall B
9:00 AM - FF8.01
Boron Nitride Nanoparticles for Safe and Efficient Hydrogen Storage and Transportation
Samuel A. Escobar Veras 2 1 Laura Lizeth Mendez Santacruz 2 1 Frank Mendoza 2 1 Vladimir Makarov 2 1 Jose E. Nocua 1 Brad Weiner 2 3 Gerardo Morell 2 1
1Universidad de Puerto Rico Rio Piedras Campus San Juan USA2Institute for Functional Nanomaterials San Juan USA3University of Puerto Rico, Rio Piedras Campus San Juan USAShow Abstract
Boron Nitride (BN) nanoparticles were synthesized employing hot filament chemical vapor deposition technique; using borazine as its gas precursor. These samples have been characterized to reveal their morphology, their chemical components, and their structure; using techniques such as the scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) & Fourier transform spectroscopy (FTIR). In previous analysis it has been shown that BN interacts with hydrogen gas, enhancing its electrical resistance. It has been shown that significant amounts of hydrogen gas adsorbed in the BN nanoparticles, making it a suitable material for safe hydrogen storage and transportation applications that can facilitate the utilization of new energy technologies, such as fuel cells. The BN nanoparticles show great cycleability in such the H adsorption-desorption processes without degradation or poisoning.
9:00 AM - FF8.02
Sensing, Capture and Storage of Carbon Dioxide
Chandrani Chatterjee 1 Ayusman Sen 1
1Pennsylvania State University University Park USAShow Abstract
Carbon dioxide emission from anthropogenic sources is a chief source of greenhouse gas in terrestrial atmosphere. Carbon dioxide is the most abundant byproduct of all respiration, fermentation and combustion processes, leading to a steady increase in concentration by 2.07 ppm every year. Thus, the sensing, capture and storage of carbon dioxide has become crucial to control and consequently reduce the emission of carbon dioxide, to curtail environmental pollution.
Classical approaches towards carbon dioxide capture from concentrated sources usually require two mols of primary or secondary amines to capture one mol of carbon dioxide in the form of ammonium carbamate salts. In the current approach a series of solid-supported tertiary amino alcohol adsorbents are developed for more efficient uni-molecular capture of carbon dioxide. The energy efficient pressure-swing carbon dioxide desorption process also makes these materials more advantageous over the classical adsorbents, which entail thermal regeneration. The application of these tertiary amino alcohols is further extended to develop reusable, inexpensive colorimetric sensors for the facile detection of small amounts of gaseous carbon dioxide. The visible detection range is 2-20%, encompassing the concentrations of carbon dioxide in ambient air or flue gas. These materials have potential use in food, beverage, as well as mining and chemical industries.
9:00 AM - FF8.03
Superwetting Nanofibrous Membranes for Effective Oil-Water Separation
Na Wang 1 Aikifa Raza 1 Jianyong Yu 2 Bin Ding 2
1Donghua University Shanghai China2Donghua University Shanghai ChinaShow Abstract
As engineers strive to develop a practical and energy-efficient method with high efficacy to separate oil/water mixtures, especially those stabilized by surfactants has proven to be extremely challenging. Here, we describe a powerful yet economic strategy for the synthesis of superhydrophilic and prewetted oleophobic nanofibrous membranes by the facile combination of in situ cross-linked polyethylene glycol diacrylate nanofibers supported on polyacrylonitrile/polyethylene glycol nanofibrous (x-PEGDA@PG NF) membranes. The as-prepared x-PEGDA@PG NF membranes have shown superhydrophilicity with ultralow time of wetting and promising oleophobicity to achieve effective separation for both immiscible oil/water mixtures and oil-in-water microemulsions solely driven by gravity. These new membranes are endowed with good mechanical strength of 14 MPa and very high flux rate of 10,975 L m-2 h-1 with extremely high separation efficiency (residual oil content in filtrate is 26 ppm). More importantly, the membrane exhibits high separation capacity, which can separate 10 L of an oil/water mixture continuously without a decline in flux and excellent antifouling property for long term use. These suggested that this cost-effective membrane could be used as promising materials for treating wastewater produced in industry and daily life, crude oil, especially for high viscosity oil purification.
9:00 AM - FF8.04
Nanoporous Carbon Membranes for the Purification of Oil-Contaminated Water
Yoshihisa Fujii 1 Sadaki Samitsu 1 Izumi Ichinose 1
1National Institute for Materials Science Tsukuba JapanShow Abstract
It is not easy to solve the ongoing issues of worldwide environmental pollution. In both the chemical and petrochemical industries, the nanofiltration of organic solvents may make a significant contribution to improved energy efficiency in the production process. Polymer-based membranes are widely used for gas separation, filtration, desalination of seawater, wastewater treatment, etc. Chemical, petrochemical, energy and environment-related industries, however, strongly require highly durable membranes applicable under extreme conditions, since the present polymeric membranes gradually or sometimes rapidly deteriorate with time due to undesired swelling, clogging, and chemical reactions. In our poster presentation, new porous diamond-like carbon (DLC) membranes will be discussed. The DLC was first prepared by Aisenberg and Chabot by means of an ion-beam deposition technique . At present, a widely used technique for DLC deposition is plasma chemical vapor deposition (CVD) using organic compounds. In the plasma CVD of organic compounds, a highly cross-linked network of sp3 carbons is obtained under certain conditions, resulting in thin carbon films with mechanical stability comparable to that of diamond. DLC has been seemed to be extremely dense and it is used mainly for gas barrier applications. In contrast, recently, we successfully prepared nanoporous DLC membranes which exhibited extremely high permeability to water and organic solvents while maintaining a considerable degree of mechanical strength [2, 3]. We believe that the nanoporous carbon membranes open the way for the water treatment.
 S. Aisenberg and R. Chabot: J. Appl. Phys., 42, pp. 2953minus;2958 (1971).
 S. Karan, S. Samitsu, X. Peng, K. Kurashima and I. Ichinose: Science, 335, pp. 444minus;447 (2012).
 S. Karan, Q. Wang, S. Samitsu, Y. Fujii and I. Ichinose: J. Membr. Sci., 448, pp. 270minus;291 (2013).
9:00 AM - FF8.05
Synthesis and Characterization of Silica-Cobalt Core-Shell Nanoparticles and Their Catalytic Applications
Yan Zhang 1 Fan Gao 1 Zhiyong Gu 1
1University of Massachusetts Lowell Lowell USAShow Abstract
As one of the most widely studied hybrid nanostructures, core-shell nanoparticles are attracting more and more attention, since properties arising from either core or shell materials can be quite different. Currently, core-shell nanoparticles have been used for many applications, including catalysis, environmental remediation, information storage, biomedical imaging, and energy harvesting. The aim of this work is to synthesize precisely controlled silica-cobalt (SiO2-Co) core-shell nanoparticles for catalytic applications. The core material of SiO2 nanoparticles has been synthesized by the Stöber method. Then, the SiO2 nanoparticles were subjected to surface modification with 3-aminopropyltrimethoxysilane. The Co shell with controlled thickness was formed by a chemical reduction method. The size and morphology of the SiO2-Co core-shell nanoparticles have been characterized by the field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The SiO2-Co core-shell nanoparticle has been used as a catalyst to degrade methyl orange, a common azo dye containing azo functional group (-N=N-). The degradation characteristics and kinetics were investigated by measurement of the absorption of the dye solution with a UV/Vis spectrometer. Kinetic studies revealed that both the surface adsorption and degradation contributed to the absorption spectra. Reductive degradation by the SiO2-Co core-shell nanoparticle catalyst is a very promising approach to the remediation of azo dye containing waste water due to the fast degradation rate and high degradation efficiency.
9:00 AM - FF8.06
Cobalt Carbide Catalysts for Fischer-Tropsch Synthesis: Formation, Activation, and Regeneration
Geunjae Kwak 1 Yun-Jo Lee 1 Ki-Won Jun 1
1Korea Research Institute of Chemical Technology (KRICT) Daejeon Korea (the Republic of)Show Abstract
Carbide has been considered as important phase in two commercial Fe and Co catalysts for Fisher-Tropsch synthesis (FTS). Iron carbide has known to be more active in FTS than metal iron and dominant phase rather than metallic Fe under FT reaction condition. On the other hand, the cobalt carbide (Co2C) is not directly involved in FTS. The formation of Co2C occurs easily under low H2/CO ratio (< 1) conditions and has been considered rather as a deactivation route of cobalt-based catalyst during FTS. However, the produced Co2C could be activated to Cohcp phase in slurry phase by H2 bubbling at a relatively low temperature of 220 °C. We experimentally demonstrated that the Cohcp catalyst activated from Co2C showed higher catalytic activities in slurry phase FTS, compared with Cofcc reduced from cobalt oxide. In this study, for high catalytic performances in FTS, we reported an optimum procedure for preparing cobalt carbide depending on the process temperature and pressure, and also demonstrated the simple route for the activation of the cobalt carbide. We could clarify the activated condition of Co2C. Also, we considered the application in regeneration of deactivated cobalt catalyst, using the formation of Co2C and subsequent hydrogenation. It was confirmed that this carburization-hydrogenation treatment could enhance the catalytic activities of the regenerated Cohcp in FTS rather than the initial activities of the cobalt catalyst.
9:00 AM - FF8.07
Control of Osmosis and Desalination Driven by Lower Critical Solution Temperature Phase Transition Materials
Yeongbong Mok 1 Yan Lee 1
1Seoul National University Seoul Korea (the Republic of)Show Abstract
The global water poverty crisis is now becoming a problem of serious concern all over the world. To obtain fresh water from seawater, recently a forward osmosis (FO) process has been developed as an attractive alternative to distillation and reverse osmosis. FO uses a 'draw solution' to osmotically pump water molecules out from feed solutions through a semipermeable membrane. Solutes in this draw solution are separated to produce usable water. However, the FO method for practical desalination remains problematic given its drawing system, low drawing power, energy costs, complicated separation, and difficult recovery of the draw solutes. In this study, we present an innovative method based on draw solutes with lower critical solution temperature (LCST) phase separation from water to induce the abrupt change of effective concentrations and osmotic pressure.
Because temperature-sensitive materials show temperature-driven hydrophilic to hydrophobic transition in aqueous condition, corresponding abrupt changes of effective concentration in the solution containing those materials could induce conversion of osmotic flows. Derived from the structure of LCST polymer, we synthesized N-acylated tris(2-aminoethyl)amine (nBu-TAEA). It has low MW (356g/mol) and shows LCST-type phase separation above ~27 Celsius. nBu-TAEA aqueous solution showed clear conversion of osmotic pressure upon low and high temperature. The nBu-TAEA solution could draw fresh water from a seawater (0.6 M NaCl) at the temperature below the phase separation point, and release the drawn fresh water into low-salt water at higher temperatures. Finally, a new desalination system was produced via circulation of the draw solutions between low and high temperature sets allowing direct seawater-drawing, transfer and release of water, and separation and recovery of draw solutes in a simultaneous and continuous manner with high energy efficiency.
9:00 AM - FF8.08
Theoretical Study of Contact-Mode Triboelectric Nanogenerators as an Effective Power Source
Simiao Niu 1 Sihong Wang 1 Long Lin 1 Ying Liu 1 Yu Sheng Zhou 1 Youfan Hu 1 Zhong Lin Wang 1
1Georgia Institute of Technology Atlanta USAShow Abstract
Scavenging mechanical energy from the ambient environment has attracted worldwide attention and is also an important way to realize sustainable development since mechanical energy is a zero-carbon emission, and widely available energy source. Among all of the available technologies of mechanical energy harvesting, contact-electrification enabled nanogenerators, i.e. triboelectric nanogenerators (TENGs) emerge as a new energy technology with numerous advantages, including large output power, high efficiency, and easy fabrication with low cost. The basic working principle for TENGs is a combination of contact electrification and electrostatic induction. The contact-mode TENG has been demonstrated to have numerous applications both as a power source and as an active sensor. However, there is still a lack of a systematic theoretical model in this field. Experimentally, it is known that the maximum power on a load as provided by the TENG is a result of matching between the TENG and the load. However, a thorough theoretical understanding about how the structural parameters and operation conditions of a TENG affect the match with the load is still missing, which is critical for designing a compatible TENG for a specific application.
In this work, a comprehensive theoretical model is built for the contact-mode TENG. Utilizing the derived equation, the real-time output characteristics of the TENG are mathematically modelled and the equivalent circuit model of TENG was derived. Then based on the calculation results, we clarified the physics behind the three-working-region behavior and the optimum load resistance. The optimum load resistance is formed because of the impedance match of internal TENG capacitance and load resistance. Finally, the quantitative relationship of the optimum resistance with the parameters of TENG is derived to provide guidance for rational design of TENGs for a specific load. This work is the first in-depth interpretation and analysis of the contact-mode TENG&’s working principle, clearly showing its unique operation characteristics, which will be able to serve as important guidance for rational design of the device structure as a power source in specific applications and self-powered systems. 
1. Simiao Niu, Sihong Wang, Long Lin, Ying Liu, Yu Sheng Zhou, Youfan Hu, and Zhong Lin Wang, Energy & Environmental Science 6 (12), 3576 - 3583.
9:00 AM - FF8.09
Effect of Multivalent Inorganics and Various Organics on the Performance of Ion-Exchange Membranes in Reverse Electrodialysis
Jin-Soo Park 1 Dong-Ju Lee 1 Chan-Soo Kim 2 Young-Woo Choi 2
1Sangmyung University Cheonan Korea (the Republic of)2Korea Institute of Energy Research Jeju Korea (the Republic of)<