Self‐Selective (220) Directional Grown Copper Current Collector Design for Cycling‐Stable Anode‐Less Lithium Metal Batteries

Abstract

Anode‐less lithium metal batteries (ALLMB) are promising candidates for energy storage applications owing to high‐energy‐density and safety characteristics. However, the unstable solid electrolyte interphase (SEI) formed on anode copper current collector (CuCC) leads to poor reversibility of uneven lithium deposition/stripping. Though the well‐known knowledge of lithium salt‐derived inorganic‐rich SEI (iSEI) benefiting uniform lithium deposition, how to design a lithium salt‐philic CuCC with undiscovered salt‐philic facet that favors lithium salt adsorption and catalyzing salt decomposition into iSEI, remains unexplored yet. Here, a self‐selective and iSEI‐catalyzing CuCC design is developed by using lithium salt as surface‐controlling agent in CuCC electrodeposition process, self‐selecting out and guiding unidirectional Cu(220) facet growth as the most salt‐philic facets of CuCC. This self‐selected Cu(220) facet promotes the salt adsorption and formation of salt decomposition‐derived iSEI in battery, thus improving the lithium plating/stripping coulombic efficiency from 99.25% to 99.50% (stable within 400 cycles), and the capacity decay rate of ALLMB is also reduced by 42.4% within 100 cycles. Practical mass‐productivity of this self‐selective CuCC for 350 Wh kg−1 pouch‐cell fabrication is also demonstrated, providing a new self‐selective current collector design strategy for improving selectivity and catalyzation of desired chemical reaction, important for high‐selectivity electrochemical reaction system construction.