Constructing a honeycomb-like channel in OPBI-based separator to suppress the disordered growth of lithium dendrites for safer lithium-ion batteries

The growth of disordered lithium dendrites on the anode and the limited thermal stability of commercial polyolefin separators present significant challenges to the safe utilization of lithium-ion batteries (LIBs). In this study, we have successfully developed a hybrid separator capable of inhibiting lithium dendrite formation and withstanding high temperatures. By leveraging the interaction between MXene structural features and diffusion forces, we have introduced a novel honeycomb channel structure. This unique design enables the hybrid separator to facilitate the uniform deposition of lithium ions on the anode and effectively suppress the irregular growth of lithium dendrites. The Li/OPBI@MXene/Li symmetric cell exhibits remarkable long-term cycling stability, sustaining continuous operation for 800 h at a current density of 1 mA cm−2. Furthermore, due to the excellent thermal stability of the hybrid separator, the cell can operate safely and reliably under high-temperature conditions. Additionally, the hybrid separator demonstrates improved electrolyte absorption capacity (590%) and higher ionic conductivity (1.83 mS cm−1). When assembled with the hybrid separator, the LiFePO4/Li cell exhibits a discharge specific capacity of 135.9 mA h g−1. Notably, the capacity retention rate remains high at 93.4% even after 200 cycles.