Flexible and hyper ion-conductive LATP-embedded semi-interpenetrating polymer network electrolyte membrane for solid-state lithium battery

In this study, hybrid solid electrolyte (HSE) membranes are fabricated by embedding Li1.3Al0.3Ti1.7(PO4)3 (LATP) nanoparticles into the semi-interpenetrating network of polyacrylonitrile (PAN)/poly (ethylene glycol) dimethacrylate (PEGDA) for solid-state lithium metal battery. The semi-interpenetrating network, established by cross-linking of PEGDA, is designed to optimize polymer morphology for high Li+ conduction. The integration of LATP, a NASICON-type Li-ion conductor, serves the dual purpose of elevating the single Li+ ion conductivity while bolstering the mechanical integrity of the membrane. The synthesized HSE membrane shows outstanding Li+ conductivity of 1.06 × 10−3 S cm−1, and a lithium transference number of 0.64 at room temperature, exhibiting good flexibility and a tensile strength of 1.76 MPa and Young's modulus of 0.1 GPa. It also possesses durability with a broad electrochemical window of up to 4.8 V vs. Li+/Li, maintaining the long-term stability with Li metal over 1000 cycles at room temperature. Owing to those superior attributes, the LFP|HSE|Li cell shows an excellent discharge capacity of 164 mAh g−1 at 0.2C, maintaining the coulombic efficiency of approximately 99% after 120 cycles at room temperature.