Solid polymer electrolyte with in-situ generated fast Li+ conducting network enable high voltage and dendrite-free lithium metal battery

Solid polymer electrolytes (SPEs) with profound compatibility for high-voltage cathodes and reliable operation over a board temperature range are in urgent demand for the practical application of solid lithium metal batteries (SLMBs). In this study, a SPE containing interconnected fast Li+ conducting network was constructed via an in-situ hydrolysis of tetraethoxysilane (TEOS) within polyacrylonitrile (PAN) matrix to intensify the thermal stability of SLMBs. The in-situ formed interconnected inorganic network not only acts as a robust backbone for the whole SPE, but also furnishes sufficient continuous surfaces with Lewis-acidic sites, which will promote the dissociation of Li salt. As a consequence, the fabricated SPE exhibits an promising ionic conductivity of similar to 0.35 mS cm(-1), an attractive Young' modulus of 8.627 Gpa and a satisfactory lithium-ion transference number of 0.52. Solidstate nuclear magnetic resonance (S-NMR) and X-ray photoelectron spectroscopy (XPS) techniques were used to unravel the interactions among Li+ ions, PAN and as-formed SiO2. Based on the in-situ formed SPE, a Li/LiFePO4 SLMB presents an excellent cycle stability from 20 to 80 degrees C and a Li/LiNi0.6Mn0.2Co0.2O2 SLMB shows a steady discharge capacity of 173.1 mAh g(-1) with 93.8 % retention after 200 cycles at 4.3 V. Additionally, the Li/LiFePO4 pouch cell also delivers a stable cyclability and superior safety for practical applications. The design strategy of our work provides a rigid - flexible coupling dynamic strategy to fabricate SPEs for wide-temperature applicability and high energy density SLMBs.

Automated summary

This study presents a solid polymer electrolyte (SPE) with a fast Li+ conducting network, enhancing thermal stability and performance of solid lithium metal batteries (SLMBs). The SPE showed promising ionic conductivity and Young's modulus, leading to stable cycling performance in wide temperature ranges and high energy density for practical applications. The design strategy provides a dynamic approach for fabricating SPEs with wide-temperature applicability and high energy density SLMBs.