Lithiophilic Montmorillonite as a Robust Substrate for Uniform Lithium Deposition and Enhanced Electrochemical Performance

Lithium metal is a highly promising anode material due to its exceptional theoretical capacity and low redox potential. However, issues such as uneven lithium deposition and uncontrolled volume expansion during cycling lead to cracks on the solid electrolyte interface (SEI), resulting in electrolyte consumption and dendrite growth. These challenges impede the commercial development of lithium metal batteries by causing poor performance, low Coulombic efficiency (CE), and safety concerns.<br/>In this study, we investigate the potential of lithiophilic montmorillonite (MMT), a two-dimensional interlayered phyllosilicate material, as a robust substrate for achieving uniform lithium deposition and enhancing electrochemical performance. MMT possesses an interlamellar structure with an octahedron layer of aluminum oxygen sandwiched between two tetrahedron layers of silicon oxygen. This interlayered structure provides pathways for the transportation of exchangeable cations, including Li⁺, Na⁺, K⁺, and Ca²⁺. We focus on lithiophilic MMT as it exhibits a strong affinity for lithium ions.<br/>By utilizing MMT as a substrate, we demonstrated the maintenance of uniform lithium deposition, which promotes enhanced electrochemical performance. The interlayered MMT structure facilitates fast diffusion channels for lithium ions and provides sufficient space to accommodate volume expansion, effectively leading to a dendrite-free lithium surface. To validate the stability of the lithium deposition process, we conducted in situ optical microscopy analysis and utilized COMSOL Multiphysics simulations. Our results showcase the effectiveness of MMT@Cu as an electrode material, achieving an average Coulombic efficiency of 99% over 700 cycles at a current density of 2 mA cm^-2 with a lithium areal capacity of 1 mAh cm^-2. Additionally, the symmetric cell incorporating MMT@Cu demonstrates an extended lifespan of 20,000 minutes at 1 mA cm^-2 for a 1 mAh cm^-2 capacity. This work presents a novel strategy for suppressing dendrite growth and ensuring high-performance lithium metal batteries. The utilization of lithiophilic MMT as a substrate for uniform lithium deposition holds great promise in overcoming the challenges associated with lithium metal anodes, paving the way for the development of advanced lithium metal batteries with improved performance and safety.