A solid-state electrolyte based on electrochemically active LiMn₂O₄ for lithium metal batteries

The key to the practical application of lithium metal batteries (LMBs) lies in developing solid state electrolytes (SSEs) that are simple to prepare and exhibit excellent performance. In this work, commercial and cheap cathode material LiMn₂O₄ (LMO) is used as an SSE and mixed with poly(vinylidene difluoride) (PVDF) to create SSEs aimed at improving interfacial stability and electronic insulation. The LMO-3 SSE, containing 30 wt% LMO, demonstrates high ionic conductivity (5.17 × 10⁻⁴ S cm⁻¹ at 35 °C), low electronic conductivity (<10⁻⁹ S cm⁻¹), and good interfacial contact and stability with both the lithium metal anode and LiFePO₄ (LFP) cathode. The Li‖LFP cell with LMO-3 exhibits good cycling stability at a current density of 0.5C (200 cycles, maintaining a discharge specific capacity of 147.7 mA h g⁻¹, with a capacity retention rate of 96.0% and a coulombic efficiency of 99.8%). This study provides a direction for the application of LMO in high-performance SSEs and LMBs, paving another economical route to the commercialization of solid-state lithium metal batteries.