Conformal 3D Li/Li₁₃Sn₅ Scaffolds Anodes for High-Areal Energy Density Flexible Lithium Metal Batteries

Achieving a high depth of discharge (DOD) in lithium metal anodes (LMAs) is crucial for developing high areal energy density batteries suitable for wearable electronics. Yet, the persistent growth of dendrites compromises battery performance, and the significant lithium consumption during pre-lithiation obstructs their broad application. Herein, A flexible 3D Li₁₃Sn₅ scaffold is designed by allowing molten lithium to infiltrate carbon cloth adorned with SnO₂ nanocrystals. This design markedly curbs the troublesome dendrite growth, thanks to the uniform electric field distribution and swift Li⁺ diffusion dynamics. Additionally, with a minimal SnO₂ nanocrystals loading (2 wt.%), only 0.6 wt.% of lithium is consumed during pre-lithiation. Insights from in situ optical microscope observations and COMSOL simulations reveal that lithium remains securely anchored within the scaffold, a result of the rapid mass/charge transfer and uniform electric field distribution. Consequently, this electrode achieves a remarkable DOD of 87.1% at 10 mA cm⁻² for 40 mAh cm⁻². Notably, when coupled with a polysulfide cathode, the constructed flexible Li/Li₁₃Sn₅@CC||Li₂S₆/SnO₂@CC pouch cell delivers a high-areal capacity of 5.04 mAh cm⁻² and an impressive areal-energy density of 10.6 mWh cm⁻². The findings pave the way toward the development of high-performance LMAs, ideal for long-lasting wearable electronics.