Conducting Composite Polymer-Based Solid-State Electrolyte with High Ion Conductivity via Amorphous Condensed Structure and Multiple Li⁺ Transport Channels

Traditional PEO electrolyte has high crystallinity which hinders the transmission of Li⁺, resulting in poor ion conductivity and complicated processing technology. Herein, a polymer electrolyte (p-electrolyte) with a wide electrochemical window and high ionic conductivity is designed, which possesses an amorphous condensed structure. The amorphous structure provides fast transport channels for Li⁺, so the p-electrolyte possesses an electrochemical window of 4.2 V, and high ionic conductivity of 1.58 × 10^-5 S cm^-1 at room temperature, which is 1-2 orders of magnitude higher than that of traditional PEO electrolyte. By using the designed polymer electrolyte as the foundation, an in situ curable composite polymer electrolyte (CPE-L) with multiple Li⁺ transport channels is elaborately constructed. The Cu-BTC MOF stores abundant Li⁺, which is introduced into the p-electrolyte. The rich unsaturated Cu²⁺ coordination sites of Cu-BTC can anchor TFSI^- to release Li⁺, and the pore structure of Cu-BTC MOF cooperates with LLZTO nanoparticles to provide multiple fast transport channel for Li⁺, resulting in remarkable ionic conductivity (1.02 × 10^-3 S cm^-1) and Li⁺ transference number (0.58). The Li||CPE-L||Li symmetric battery cycles stably for more than 700 h at 0.1 mA cm^-2, while the specific capacity of full battery is ≈153 mAh g^-1 (RT, 0.2 C).