Inorganic all-solid-state sodium batteries: Electrolyte design, interface engineering, and multiscale approaches

In the realm of large-scale power system energy storage, sodium-based batteries represent a cost-effective post-lithium energy storage technology, making inorganic solid-state sodium batteries (ISSSB) a critical branch of this development. Inorganic solid-state electrolytes (ISSEs) are the core components of sodium batteries; however, they face significant challenges such as insufficient ionic conductivity, interfacial instability, and dendrite growth, all of which severely hinder practical application. This review critically assesses experimental protocols and theoretical frameworks related to mainstream ISSEs and systematizes optimization strategies aimed at overcoming these challenges. Leveraging integrated insights from both experimental and computational studies, the review first categorizes and summarizes the primary types of ISSEs, namely oxide-, sulfide-, and halide-based electrolytes. It then details interfacial optimization strategies focused on addressing three core interfacial issues: ion transport barriers resulting from mechanical incompatibility, side reactions stemming from electrochemical mismatch, and dendrite formation. Finally, the review advocates prioritizing in-depth research that integrates experimental and theoretical approaches to establish a closed-loop methodology encompassing predictive design, multiscale investigation, mechanistic exploration, and high-throughput automated experimentation, with feedback-driven refinement. This work serves as a comprehensive reference and systematic roadmap for future research on solid-state electrolytes (SSEs).