Monodispersed Sub‐1 nm Inorganic Cluster Chains in Polymers for Solid Electrolytes with Enhanced Li‐Ion Transport

Abstract The organic–inorganic interfaces can enhance Li + transport in composite solid‐state electrolytes (CSEs) due to the strong interface interactions. However, Li + non‐conductive areas in CSEs with inert fillers will hinder the construction of efficient Li + transport channels. Herein, CSEs with fully active Li + conductive networks are proposed to improve Li + transport by composing sub‐1 nm inorganic cluster chains and organic polymer chains. The inorganic cluster chains are monodispersed in polymer matrix by a brief mixed‐solvent strategy, their sub‐1 nm diameter and ultrafine dispersion state eliminate Li + non‐conductive areas in the interior of inert fillers and filler‐agglomeration, respectively, providing rich surface areas for interface interactions. Therefore, the 3D networks connected by the monodispersed cluster chains finally construct homogeneous, large‐scale, continuous Li + fast transport channels. Furthermore, a conjecture about 1D oriented distribution of organic polymer chains along the inorganic cluster chains is proposed to optimize Li + pathways. Consequently, the as‐obtained CSEs possess high ionic conductivity at room temperature (0.52 mS cm −1 ), high Li + transference number (0.62), and more mobile Li + (50.7%). The assembled LiFePO 4 /Li cell delivers excellent stability of 1000 cycles at 0.5 C and 700 cycles at 1 C. This research provides a new strategy for enhancing Li + transport by efficient interfaces.