(133g) PEGDA-ZIF-8 Composite Electrolyte for All-Solid-State Lithium Metal Batteries

Li metal is considered to be the most promising anode for high-energy batteries as it has a high specific capacity and low electrochemical potential. However, traditional liquid electrolytes can’t meet the practical application requirement due to safety issues. Solid-state polymer electrolytes (SPE) with low flammability, wide electrochemical stability window, and sufficient mechanical stability have been developed to address the battery safety issues. Still, polymers tend to recrystallize at room temperature, leading to insufficient ionic conductivity. Metal-organic frameworks have been found to effectively increase the ionic conductivity of SPEs by decreasing the crystallinity polymer, immobilizing anions, and improving Li⁺ transfer ability. Porous zeolitic imidazolate framework-8 (ZIF-8) has been used as fillers in this study. The ZIF-8 particles are intergraded with the Polyethylene Glycol Diacrylate (PEGDA) matrix with a simple UV-curing process in this study. The resulted composite electrolyte delivers a room Li⁺ ion conductivity of 3.6 × 10^−4 S cm^−1 and outstanding electrochemical stability with a wide electrochemical window of 0–4.8 V (versus Li/Li⁺). The good performance is due to the composite solid-state electrolyte inherited the advantages of both polymer and fillers. On one hand, the polymeric PEGDA enhanced the contact interphase between the electrolyte and electrodes. On the other hand, fillers can inhibit the recrystallization of the polymer, improve Li⁺ transfer ability, as well as prevent dendrite growth. The simple fabrication process and good electrochemical performance of PEGDA-ZIF-8 composites are of great promise for all-solid-state lithium metal batteries.