Stress-induced challenges in sodium-ion battery layered oxide cathodes: Damage mechanisms and mitigation approaches

Amid the global transition toward clean and sustainable energy systems, the development of cost-effective and resource-abundant energy storage technologies has become increasingly critical. Sodium-ion batteries have emerged as a highly promising candidate due to their material availability and competitive performance. Nevertheless, the practical application of layered oxide cathode materials in these batteries is hindered by mechanical stress accumulation during cycling, which leads to structural degradation, capacity fade, and ultimately battery failure. This review systematically summarizes recent advances in stress engineering strategies aimed at mitigating these challenges. It begins by elucidating the fundamental mechanisms of stress generation associated with sodium ion intercalation and deintercalation processes. The article then provides a comprehensive analysis of various innovative approaches designed to manage stress, including microstructural optimization, surface and interface engineering, and composite material design. Furthermore, it discusses the correlation between atomic-scale lattice strain and macroscopic electrochemical behavior, offering deep insights into failure mechanisms. By integrating theoretical understanding with experimental progress, this review aims to provide valuable guidance for the rational design of durable and high-performance cathode materials, thereby supporting the broader effort to develop reliable sodium-based energy storage systems.