Synergetic regulation of bulk reconstruction and preferential orientation realizing long-lifespan thin Li anodes for high-energy-density lithium metal batteries

Abstract

Li plating behavior of the Li metal anode and its compatibility with electrolytes play a decisive role in the electrochemical performance of the Li metal batteries (LMBs), while the intrinsic highly reactive Li would induce serious results especially under deep Li plating/stripping depth and with lean electrolytes. Herein, we propose an innovative strategy to simultaneously regulate the bulk construction and the preferential orientation of Li deposition by introducing Li₂₂Sn₅/Li-Mg alloys to realize ultra-stable thin Li anodes with long lifespan. The alloys can form a continuous framework with high lithiophilicity and fast ion-diffusion to enable homogenous Li⁺ flux, and meanwhile tune the preferential orientation of Li from the conventional (1 1 0) plane to (2 0 0) to lower the Li reactivity with electrolytes and optimize Li deposition. Therefore, the thin Li-Sn-Mg alloy anode showcases ultra-stable cycling without volume changes and dendrites under a deep Li plating/stripping depth of 89.1% (5 mAh cm⁻²) for over 1200 h in commercial carbonate electrolytes. Moreover, a multilayered NCM₈₁₁ pouch cell with a high energy density of 403.6 Wh kg⁻¹ is achieved under the harsh conditions of low N/P ratio (0.769) and lean electrolytes (∼2.1 g Ah⁻¹). Synchronously, the thin alloy anode shows improved air stability which benefits the manufacturing process and performance of LMBs, displaying the great application potential of these alloy anodes.