Synergistic Integration of LLZAO-Based Hybrid Membrane and Quasi-Solid Electrolyte for High-Performance and Thermally Stable Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have been extensively used in various energy storage systems, such as mobile electronics and electric vehicles. However, the growing demand for higher energy density and improved safety necessitates alternative electrolyte systems to replace conventional liquid electrolytes. In this work, we prepared a hybrid quasi-solid-state electrolyte (HQSE) incorporating a Li+-conducting oxide electrolyte. To fabricate the HQSE, a porous hybrid membrane was formed using poly(vinylidene fluoride-co-hexafluoropropylene) and fibrous Li6.4La3Zr2Al0.2O12 (LLZAO) via a phase-inversion method. The hybrid membrane was then impregnated with a precursor solution containing liquid electrolyte and cross-linking agent, followed by thermal curing to finally obtain the HQSE. The resulting HQSE exhibited excellent oxidative stability, high ionic conductivity, high Li+ transference number, nonflammability, and enhanced thermal stability. The graphite/LiNi0.8Co0.1Mn0.1O2 cell employing the HQSE delivered a high initial capacity of 188.8 mAh g–1 at 0.5C and 25 °C, along with excellent capacity retention of 85.2% at 25 °C and 62.4% at 55 °C after 500 cycles, outperforming the cell with liquid electrolyte. Our results demonstrate that the developed HQSE offers a promising alternative to conventional liquid electrolytes, enabling high performance and enhanced safety in LIBs.