An All-from-one Strategy to Flexible Solid-State Lithium-Ion Batteries with Decreased Interfacial Resistance

Solid-state lithium-ion batteries (SSLIBs) are recognized ideal energy storage devices in wearable electronics due to their instinctive safety and high energy density. However, the reduction of electrode/electrolyte interfacial resistance still remains challenges. Here, we report an all-from-one strategy to decrease interfacial resistance of SSLIBs by introducing thermoplastic polyurethane (TPU) as a highly ionic conductive scaffold for both flexible electrodes and solidstate electrolytes. It was demonstrated that the functional groups (–C=O,–NH, and–C–O–C–groups) of the TPU facilitate Li-ion transport. With this feature, TPU-based solidstate electrolytes and composite electrodes with impressive flexibility were facilely fabricated via a scalable tape-casting strategy. The typical TPU-based solid-state electrolyte exhibits excellent flexibility and high ionic conductivity of 1.20×10−4 S cm−1 at room temperature. The resultant composite cathode/anode provides impressive mechanical flexibility to maintain acceptable electrochemical performance even under various deformations. These comprehensive attributes enable the successful assembly of all-from-one flexible SSLIBs, in which the interfacial adhesion between the electrode and solid-state electrolyte was significantly reinforced since the compatibility in the similar material structure. Consequently, the as-obtained all-from-one SSLIB shows reduced interfacial resistances and can operate at 0.3 C with a Coulombic efficiency exceeding 99