Abstract

Polymer/ceramic composite electrolytes have recently received a lot of attention because they combine the advantages of inorganic ceramic's high ionic conductivity and the inherent elasticity of polymer constituents. Nonetheless, the interaction between the ceramic particles and the polar functional groups on the polymer molecules would affect the ion transport rate, which is an important factor to consider when developing a polymer/ceramic composite electrolyte. We present a composite elastic electrolyte based on polyurethane (PU) with high ionic conductivity of 10^–3 S/cm and excellent mechanical properties (stress-strain) of 4.5 MPa by incorporating ceramic particles into the ion conduction chains on PU. This method improves the interaction between PU/LGPS and Li⁺ ions and the conduction of Li⁺ ions at the bi-phase interface, yielding a high Li⁺ transfer number of 0.56. After 2000 cycles, the capacity retention rates of the batteries assembled by [LFP∣(PU-LGPS)/Li⁺∣Li] are 95.7% (0.2 C) and 87.8% (5 C), respectively. The Li symmetric battery test demonstrates the PU/LGPS composite electrolyte's high stability over 50 days. The current study presents a novel approach to develop high-performance ceramic/polymer composite electrolytes.