In situ fabricated ceramic/polymer hybrid electrolyte with vertically aligned structure for solid-state lithium batteries

The succinonitrile (SN) plastic crystal electrolyte with high ionic conductivity and wide electrochemical window has been a promising room-temperature solid electrolyte. In this work, the ice-templated Li1.5Al0.5Ge1.5(PO4)3 (LAGP) with vertically aligned channels is applied to improve the mechanical properties of SN, in which the LAGP particles of the ceramic skeleton are tightly bonded and form continuous connected ion transport pathways. The SN-based electrolyte is firmly locked in the microchannels of LAGP through in-situ thermal polymerization. Compared with commercial Celgard, LAGP exhibits better affinity to SN-based electrolyte, which is further confirmed by DFT calculation. The excellent affinity can be expected to provide sufficient electrolyte diffusion pathways and benefit the cycling stability of batteries. Due to the structural design, LAGP/SN hybrid electrolyte displays high ionic conductivity of 1.17 × 10−3 S•cm–1 at 30°C, superior Li+ transference number (0.77), and wide electrochemical window (0∼5.0 V vs. Li+/Li). In addition, the Li symmetric cells with this hybrid electrolyte show excellent interfacial stability over 200 h at 0.2 mA•cm−2 and high critical current density (CCD) of 1.0 mA•cm−2. The solid-state lithium batteries (LiNi0.5Co0.2Mn0.3O2/Li) provide excellent room-temperature rate capability (1 C) and stable cycling performance at 0.2 C with a retention of 90.0% after 100 cycles.