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 x 10(-3) S.cm(-1) at 30 degrees C, superior Li+ transference number (0.77), and wide electrochemical window (0 similar to 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.

Automated summary

The study utilizes ice-templated Li1.5Al0.5Ge1.5(PO4)3 with vertically aligned channels to enhance the mechanical properties and lithium ion transport efficiency of the plastic crystal electrolyte, resulting in a high ionic conductivity and wide electrochemical window for the LAGP/SN hybrid electrolyte. The affinity between LAGP and SN-based electrolyte, confirmed by DFT calculation and in-situ thermal polymerization, provides sufficient electrolyte diffusion pathways and contributes to the cycling stability of batteries. The solid-state lithium batteries employing this hybrid electrolyte demonstrate excellent room-temperature rate capability and stable cycling performance, showcasing a promising potential for practical applications.