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).