A Robust 3D Cross-Linked Polymer Layer with Controlled Silver Release for Long-Life Anode-Free Lithium Metal Batteries

Abstract

Anode-free lithium metal batteries (AFLMBs) have been intensively investigated as next-generation energy storage systems because of their high energy density and simplified fabrication processes. However, the poor interfacial compatibility between lithium and the current collector leads to uncontrollable dendrite growth and side reactions, thus hindering their practical application. In this study, a cross-linked polymer protective layer incorporating silver nitrate (Ag-CPL) is proposed, which provides both chemical and mechanical regulation of lithium deposition. The sustained release of Ag+ ions, reduced to form Li-Ag alloys, offers effective nucleation sites that promote uniform lithium plating. The protective layer exhibits a high elastic modulus of 1.2 GPa, effectively suppressing dendritic growth and facilitating uniform lithium-ion transport by promoting desolvation at the interface. As a result, an anode-free pouch cell assembled with a high-loading LiNi0.88Co0.10Al0.02O2 cathode (22.5 mg cm−2) and the Ag-CPL-coated Ni current collector delivered a high initial discharge capacity of 177.7 mAh g−1 under 80% depth of discharge and exhibited good capacity retention of 80.4% after 200 cycles at 0.5 C and 45 °C. This work demonstrates that the synergistic combination of alloy-guided nucleation and a mechanically robust polymer matrix enables stable interfacial regulation and long-term cycling in AFLMBs.