Advancing high-safety and low-cost all-solid-state batteries with polyanion cathodes: Challenges and recent progress

While conventional liquid-based lithium-ion batteries (LIBs) have powered electric vehicles (EVs) successfully in the transportation market, the transition to all-solid-state lithium-ion batteries (ASSLIBs) promise transformative benefits, including enhanced safety and significantly higher energy densities. Advancing the adoption of ASSLIBs requires prioritizing low-cost, widely available materials while reducing reliance on critical mined resources. Developing low-cobalt and cobalt-free cathodes, such as polyanion materials, offers a promising and sustainable pathway for the future of EV batteries. This review aims to explore recent advancements in polyanion cathodes for ASSLIBs, highlighting the challenges they face, and the innovative strategies developed to address them. This paper begins by analyzing the crystal structures and properties of polyanion cathodes, establishing their influence on the performance of ASSLIBs. It then focuses on the challenges and corresponding strategies for integrating LiFePO 4 (LFP) cathodes with various solid-state electrolytes (SSEs), including polymer, oxide, composite polymer/oxide, sulfide, and halide-based systems. Additionally, the application of other polyanion cathodes in ASSLIBs is thoroughly examined, providing a comprehensive overview of their potential and advancements. Through this paper, we aim to emphasize the critical importance of developing safe, cost-effective cathodes to accelerate the application of ASSLIBs in next-generation EVs and beyond. • Importance of developing safe and cost-effective cathodes for all-solid-state batteries. • Structures and properties of polyanion cathodes on the performance of all-solid-state batteries. • Challenges and mitigation strategies of polyanion cathodes paired with various solid-state electrolytes.