Work

Silica-centered crosslinking solid polymer electrolyte for sodium metal batteries

Year: 2025

Type: article

Abstract: Replacing flammable liquid electrolytes with solid polymer electrolytes (SPEs) can dramatically improve battery safety. Here, we report the development of silica (SiO 2 )-centered crosslinking SPEs by chemically bonding SiO 2 nanoparticles with the polymer matrix. This innovative design not only ensures the uniform dispersion of SiO 2 nanoparticles throughout the polymer matrix but also builds a robust interface between the nanofillers and the polymer matrix, thereby enhancing Na + ionic conductivity. Simultaneously, it leverages the abundant hydroxyl (OH) groups on SiO 2 nanoparticles to interact with ClO 4 − anions through Lewis acid-base interactions and hydrogen bonding, promoting sodium salt dissociation. Theoretical calculations corroborate these interfacial mechanisms, revealing a 5.6-fold improvement in the Na + diffusion coefficient. As a result, this pioneering design allows SPE to achieve a high Na + ionic conductivity of 7.03 × 10 −4 S cm −1 and an extended electrochemical voltage window up to 5.21 V. The assembled solid-state sodium metal batteries (with Na 3 V 2 (PO 4 ) 3 as the cathode) exhibit dendrite-free Na-metal deposition, promising rate capability, and stable cycling performance with 84.6 % capacity retention over 200 cycles at 0.2C and 64.1 % capacity retention over 200 cycles at 1C. This work introduces a transformative strategy of engineering nanofiller–polymer interactions to enhance the properties of SPEs for solid-state batteries.

Source: Chemical Engineering Journal

DOI: 10.1016/j.cej.2025.166186