Sodium-Ion Batteries: Materials, Performance, and Application in Engineering Systems

Sodium-ion batteries (SIBs) are emerging as a viable alternative to lithium-ion batteries (LIBs) due to their material sustainability and cost-effectiveness, helping address the high costs, supply limits, and environmental concerns associated with lithium. This paper reviews SIB materials, designs, and applications, and surveys their electrochemical performance, challenges, and future prospects. Recent advances in electrode materials (e.g., layered oxides, hard carbon composites, metallic alloys) are greatly improving SIB stability, conductivity, capacity, and cycle life. Improvements in both solid-state and liquid electrolytes have likewise enhanced ionic conductivity, capacity retention, thermal stability, and safety. Despite their lower energy density, SIBs tolerate wider temperature ranges and carry a significantly lower risk of thermal runaway compared to lithium-based systems, making them attractive for industrial, transportation, and large-scale power storage. Continuous progress in materials and cell engineering is narrowing the performance gap between SIBs and LIBs. Meanwhile, nascent battery recycling strategies for SIBs show promise for economic and environmental viability. Overall, SIBs represent a promising option for safer, more accessible, and more sustainable energy storage technology.