Recent Advances in LATP/Polymer Composite Electrolytes for Solid-State Lithium Batteries

Solid-state lithium batteries are considered one of the most promising next-generation energy storage technologies owing to their safety and high energy density. The key to solid-state lithium battery advancement lies in the design and optimization of suitable solid-state electrolytes. Among various solid-state electrolytes, solid-state composite polymer electrolytes offer the combined benefits of solid inorganic electrolytes and solid polymer electrolytes. In particular, Li_{1 + x}Al_xTi_{2 − x}(PO₄)₃ (LATP)/polymer composite polymer electrolytes exhibit high ionic conductivity due to LATP and improved flexibility from the polymer matrix. These systems also demonstrate robust mechanical properties and excellent electrode contact. While recent reviews have primarily focused on the performance of LATP/polymer composite polymer electrolytes and the general effects of composite polymer electrolyte modifications for solid-state lithium battery applications, this review provides a concise overview of the Li⁺ transport mechanisms in LATP/polymer composite polymer electrolytes and strategies to enhance ionic conductivity. It highlights several modification approaches, including the use of fillers, additives, and LATP coatings, which markedly influence the performance of composite polymer electrolytes across different polymer matrices. Finally, the review addresses the challenges of LATP/polymer composite polymer electrolytes and outlines key research directions for developing advanced composite polymer electrolytes for high-performance solid-state lithium batteries.