Galvanostatic deposition of lithiophilic nanosized LixSn nucleation sides and inorganic-rich@polymer dual layer for anode-free lithium metal batteries

Abstract

Anode-free lithium-metal batteries (AFLMBs) offer high energy density. However, lithium dendrite growth and interfacial instability remain critical obstacles to their commercialization. Here, lithiophilic nanosized (∼5 nm) Li_xSn combined with an inorganic-rich@polymer dual-layer structure was constructed on a Cu current collector, prepared via a galvanostatic process using a dual-lithium salt electrolyte in a Cu||Cu configuration. The polymer outer layer, initiated by Li_xSn, reinforces the solid electrolyte interphase (SEI), providing mechanical robustness and enabling stable cycling in an ether-based electrolyte. Furthermore, the Sn and Li_xSn particle sizes can be effectively tuned by adjusting the galvanostatic discharge current. The nanosized Li_xSn significantly lowers the nucleation overpotential and creates abundant lithiophilic nucleation sites, resulting in uniform, dense Li plating/stripping. The modified Cu collector demonstrates superior performance in ether-based electrolytes, achieving over 92 % capacity retention after 100 cycles at a current density of 1.5 mA cm⁻² and an area capacity of 1.1 mAh cm⁻². This work provides a simple, eco-friendly, and scalable approach for fabricating high-performance anode-free current collectors for AFLMBs.