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.