Developments and Perspectives on Emerging High-Energy-Density Sodium-Metal Batteries

Emerging rechargeable sodium-metal batteries (SMBs) are gaining extensive attention because of the high energy density, low cost, and promising potentials for large-scale applications. The mechanism investigation and performance optimization of SMBs are of great significance for fundamental science and practical applications. Consequently, this review provides fundamental insights into the cell chemistry and recent progress on several representative SMBs, including Na-O-2, Na-CO2, Na-SO2, and room-temperature Na-S batteries, for which the Na-storage mechanisms, potential solutions for enhancing battery performance, and future perspectives are discussed. We emphasize the importance and challenges of sodium-metal anodes, as well as summarize and highlight feasible strategies to address the challenging issues facing them. Combined with current research achievements, this review offers future research directions from the viewpoint of better SMB full cells regarding cathode design and anode protection with compatible electrolyte systems.