Synergistic 3D Li0.5La0.5TiO3 framework-fluoroethylene carbonate interphase engineering: Toward 500+ cycle solid-state batteries with 95 % capacity retention

The development of all-solid-state lithium batteries (ASSLBs) currently faces challenges such as the need for electrolyte materials to possess high chemical stability, high ionic conductivity, and excellent compatibility with lithium (Li) metal anodes. Herein, a facile template-free sintering method for three-dimensional porous Li 0.5 La 0.5 TiO 3 (LLTO) framework is reported. By integrating these frameworks with a poly(ethylene oxide) (PEO) matrix, a new-type composite polymer electrolyte (CPE) is fabricated. In the CPE, the crystallinity and melting point of the PEO matrix are significantly reduced, which is beneficial for enhancing the Li + conductivity and transference number. Incorporating fluoroethylene carbonate (FEC) facilitates the formation of a robust SEI layer on the Li foil surface, significantly mitigating Li dendrite growth and interfacial degradation. The optimized CPE2F electrolyte enables stable Li||Li symmetric cell cycling for over 1000 h at 0.1 mA cm −2 and demonstrates superior full-cell performance: the LiFePO 4 ||Li configuration achieving a high specific capacity of 144.5 mAh g −1 at 0.5 C and 60 °C, retaining 94.5% capacity after 500 cycles. This work provides an efficient and scalable approach for producing solid electrolytes suitable for all-solid-state batteries.