Integrative preparation of mesoporous epoxy resin–ceramic composite electrolytes with multilayer structure for dendrite-free lithium metal batteries

Abstract

Polymer/ceramic layered composite electrolytes have become promising electrolytes for Li metal batteries (LMBs) due to their high ionic conductivity, good mechanical properties, favorable wettability and excellent chemical stability to Li metal. However, the complexity of the preparation process and the increased interfacial resistance have hindered their extensive application in LMBs. To address these problems, we prepared a mesoporous epoxy resin matrix multilayer electrolyte composited with lithium lanthanum titanate (LLTO) nanoparticles (c-EME) using the traditional direct casting method. The c-EME possesses a high ionic conductivity of 2.02 × 10⁻³ S cm⁻¹, a large Li-ion transference number of 0.82, a wide electrochemical stability window of up to 5.5 V (vs. Li⁺/Li) at room temperature and a smaller interfacial resistance compared with the pure epoxy resin matrix electrolyte (EME). In addition, the c-EME with a multilayer structure could infiltrate the electrode surface sufficiently and maintain uniform Li deposition even at a high current density, up to 4 mA cm⁻², with an areal capacity of 12 mA h cm⁻². Furthermore, the assembled LiFePO₄/Li full battery with c-EME exhibits high cycling stability and superior rate performance. Our recent results provide a new avenue for developing a low cost, simple fabrication process for access to high safety and high stability LMBs based on porous epoxy resin-matrix electrolytes.