Graphene oxide/SiO2 functionalized heat-treated electrospun membranes for dendrite-free and durable lithium metal batteries

Abstract

Lithium metal batteries (LMBs) suffer from severe safety risks and limited cycle life, largely attributed to the uncontrolled growth of Li dendrites. In this work, we propose a facile modification approach to construct high-performance LMBs. A heat-treated electrospun PAN/PVDF membrane was further functionalized with graphene oxide (GO) and SiO₂ (HPPSG), which together ensured dendrite-free Li deposition and enhanced electrochemical stability. The thermal treatment significantly reinforced the mechanical robustness of the nanofiber scaffold, while GO, with abundant lithiophilic sites, guided uniform nucleation of Li. Meanwhile, SiO₂ promoted Li-ion transport, improved electrolyte affinity, and chemically consumed dendrites during cycling. Benefiting from this synergistic design, the HPPSG composite separator enabled long-term reversible plating/stripping behavior, delivering an initial capacity of 159 mAh g⁻¹ at 0.2C and maintaining 109 mAh g⁻¹ after 500 cycles at 2C (capacity retention 85.8%, decay rate 0.028%). Compared with commercial Celgard membranes, the proposed composite exhibited excellent thermal dimensional stability (intact up to 180 °C), high porosity (75%), superior electrolyte uptake (552%), and outstanding cycling stability, highlighting its potential for next-generation safe and durable LMBs.