Hybrid Polymer Electrolyte Encased Cathode Particles Interface‐Based Core–Shell Structure for High‐Performance Room Temperature All‐Solid‐State Batteries

A smooth interfacial contact between electrode and electrolyte, alleviation of dendrite formation, low internal resistance, and preparation of thin electrolyte (<20 mu m) are the key challenging tasks in the practical application of Li7La3Zr2O12 (LLZO)-based solid-state batteries (SSBs). This paper develops a unique strategy to reduce interfacial resistance by designing an interface-based core-shell structure via direct integration of Al-LLZO ceramic nanofibers incorporated poly(vinylidene fluoride)/LiTFSI on the surface of a porous cathode electrode (HPEIC). This yields an ultrathin solid polymer electrolyte with a thickness of 7 mu m. The integrated HPEIC/Li SSB with LiFePO4/C exhibits an initial specific capacity of 166 mAh g(-1) at 0.1 C and 159 mAh g(-1) with capacity retention of 100% after 120 cycles at 0.5 C (25 degrees C). The HPEIC/Li SSB with LiNi0.8Mn0.1Co0.1O2 cathode delivers a good discharge capacity of 134 mAh g(-1) after 120 cycles at 0.5 C. The rational design of interface-based core-shell structure outperforms the conventional assembly of solid-state cells using free-standing solid electrolytes in specific capacity, internal resistance, and rate performance. The proposed strategy is simple, cost-effective, robust, and scalable manufacturing, which is essential for the practical applicability of SSBs.