Scalable production of ultrathin Li-Sn-In alloy foil with interpenetrated skeleton for high-energy-density lithium metal batteries

Lithium (Li) metal holds great promise to be the ultimate anode owing to its high specific capacity and low redox potential. However, simultaneously addressing the challenges of uncontrollable dendrites growth, huge volume change, and poor processability is crucial for its practical application in next-generation high-energy-density batteries. Herein, a practical ultrathin (10 μm) Li-rich Li-Sn-In alloy (LSI) composite electrode with simultaneously optimized interphase and mechanical properties is fabricated through a scalable mechanical kneading process using Li and In₅₂Sn₄₈ foils. The stable interpenetrated InLiSn skeleton in the electrode not only accommodates volume changes but also regulates Li stripping/plating, contributing to superior performances compared to that of pure Li metal electrode. Significantly, the LSI-20||LSI-20 symmetric cell, in which the LSI electrode is produced with 20 wt % In₅₂Sn₄₈ alloy (LSI-20), exhibits stable cycling in carbonate-based electrolytes for 2700 h at 1 mA cm^-2 and 1 mAh cm^-2. The NCM95||LSI-20 coin-type full cell with an ultrahigh loading cathode (∼18 mg cm^-2) also reveals a high capacity retention of 89.2 % for 200 cycles at 0.5 C. More impressively, the NCM95||LSI-20 pouch cell with a low N/P capacity ratio of ∼ 2.0 delivers a high energy density of ∼ 495.5 Wh kg^-1 at 0.2 C, and maintains 91.7 % capacity retention over 100 cycles, demonstrating the promising practical application potential of the LSI anode in the next-generation high-energy Li metal batteries (LMBs).