Organic–Inorganic Hybrid Materials for Interface Design in All-Solid-State Batteries with a Garnet-Type Solid Electrolyte

The practical realization of all-solid-state lithium-metal batteries depends on the development of low interfacial resistance between the solid electrolyte and electrodes. Herein, an organic–inorganic hybrid solid electrolyte, formed by an organic network of poly(ethylene oxide) chains that is connected with an inorganic Si–O–Si backbone network containing lithium salt, is proposed as a new interfacial material between a garnet-type oxide solid electrolyte and high-potential cathodes. The properties of the hybrid solid electrolyte are evaluated to obtain a material that is chemically and electrochemically compatible with the solid electrolyte and active material. Thereafter, the different procedures to fabricate a low-resistance solid–solid interface between the solid electrolyte and LiCoO 2 using the hybrid solid electrolyte are evaluated. The hybrid solid electrolyte provides an ionic/electronic percolation of active material particles and excellent adherence properties, thereby enabling the operation of the all-solid-state battery at room temperature to achieve a high initial discharge capacity of 125 mAh·g –1 .