A Sandwich-structured EVA/Cu2O/Cu Composite Current Collector to Suppress the Lithium Dendrite Growth.

Abstract

The proliferation of lithium dendrites has long posed a formidable hurdle in the widespread adoption of lithium metal batteries, thereby necessitating the urgent resolution of how to effectively mitigate their growth as the paramount challenge in the realm of energy storage. Herein, we have crafted a novel sandwich-structured current collector comprising an ethylene-vinyl acetate polymer (EVA)/Cu2O/Cu configuration, where the EVA thin film acts as a protective barrier, passivating the lithium metal anode, while the Cu2O layer fosters lithiophilic sites conducive to uniform lithium nucleation. Our experiments reveal that the EVA thin film adeptly prevents direct contact and subsequent reactions between the lithium metal and the electrolyte, enhancing the ion mobility of Li+ ions, ultimately leading to a even distribution of lithium deposition. In a Li-Cu half-cell, the incorporation of the EVA film increases the nucleation potentials but dramatically reduces polarization potentials after 50 cycles of charge-discharge processes. Remarkably, the Li-Cu half-cells equipped with EVA-coated current collectors exhibit lower electrochemical resistances, translating into significantly extended cycle lives. This work indicates the sandwich architecture (thin film/lithium metal/lithiophilic compounds) is a promising contender for achieving long-lasting, stable lithium anodes.