Soft Colloidal Glasses as Solid-State Electrolytes

Solid-state electrolytes are an attractive alternative to conventional liquid electrolytes in lithium batteries because of their intrinsic safety features and superior mechanical properties. Maintaining high bulk and interfacial ion fluxes in batteries that utilize solid-state electrolytes remains a significant challenge. We report on synthesis and electrochemical properties of a class of solid-state polymer electrolytes composed of silica nanoparticles covalently grafted with poly(ethylene oxide) chains. By regulating the salt content in the materials, we find that it is possible to drive microstructural changes, including nanoparticle arrangements, to achieve appreciable levels of bulk and interfacial ionic conductivity at room temperature. Additionally, we show that electrolyte salt additives can be used to create cathode-electrolyte interphases (CEI) that increase the oxidative stability of all PEO-based electrolytes. Finally, we report that solid-state lithium batteries comprised of a high-voltage nickel cobalt manganese oxide (NCM) cathode, metallic Li anode, and a solid-state hybrid polymer electrolyte can be cycled stably with high levels of reversibility.