Enhanced ionic conductivity in PEO-based solid electrolytes via 3D hollow nanotube fillers for all-solid-state lithium batteries

Solid-state lithium metal batteries (SSLMBs) employing polymer electrolytes are considered highly promising for their superior safety and elevated energy density. However, their development is impeded by the inherently low ionic conductivity of polymer electrolytes and the poor interfacial stability at the lithium metal anode. To overcome these challenges, Li-doped three-dimensional ZnO (LZN) ceramic hollow tube networks were incorporated into a poly(ethylene oxide) (PEO)-based solid polymer electrolyte (SPE). The abundant oxygen vacancies and strong interactions with LiTFSI facilitate lithium salt dissociation, thereby generating a higher concentration of free Li⁺ ions and enhancing Li⁺ transport. Consequently, the optimized PL-20LZN composite polymer electrolyte membrane exhibits a high Li⁺ conductivity of 8.12 × 10 –4 S·cm -1 at 60 °C. The solid-state LiFePO 4 /Li cell maintains stable cycling performance over 400 cycles, with an average Coulombic efficiency of 99.8 %. Moreover, relative to the pure PEO electrolyte, the full cell employing a high-voltage LiNi 0.6 Co 0.6 Mn 0.6 O 2 (NCM622) cathode exhibits notably enhanced cycling stability, suggesting that LZN hollow nanotubes play a key role in enhancing both interfacial and high-voltage stability.