A strategy involving the use of 3D self-supporting B·N co-doped carbon nanofiber composite solid polymer electrolytes...

All-solid-state batteries (ASSBs) have gained significant attention in the field of energy storage owing to their enhanced safety features based on the nonflammable solid-state electrolyte (SSE). To achieve high energy density, lithium metal is commonly considered the best choice as an anode material. However, the compatibility issues at the interface between polymer electrolytes and lithium metal pose significant challenges to their practical implementation. In this work, we present a new strategy to protect the typical polymer electrolyte polyethylene oxide (PEO) from significant decomposition and puncture caused by lithium dendrites, which is achieved through the combination of PEO and B·N co-doped carbon nanofibers (B·N-CNF) to modify the surface of the lithium anode. The stable cycling performance of the symmetric battery can last over 900 h at a high current density of 1 mA cm^-2. The ASSBs (LiFePO₄ is used as the cathode and Li metal is employed as the anode) exhibit a high capacity close to 120 mA h g^-1 at 2C and cycle for over 300 cycles at 0.2C stably. This work provides inspiration for the rational design of a modification layer on the Li anode, enabling the development of high-performance ASSBs based on polymer electrolytes.