COMPARATIVE REVIEW OF LITHIUM-ION AND SODIUM-ION BATTERIES FOR FUTURE ENERGY STORAGE APPLICATIONS

Abstract

Sodium-ion batteries (SIBs) are emerging as a promising alternative and complementary technology to lithium-ion batteries (LIBs) due to the abundance, low cost, and wide geographical availability of sodium resources. Although LIBs currently dominate high-energy-density applications, fundamental physical and electrochemical differences between sodium and lithium ions, including the larger ionic radius and higher atomic weight of sodium, generally result in lower energy density and more challenging electrode kinetics in SIBs. In addition, the higher standard reduction potential of sodium compared with lithium contributes to a lower cell voltage, which further limits the achievable energy density. Despite these limitations, sodium-ion batteries share similar working principles and many manufacturing processes with lithium-ion systems, making them suitable for adaptation within existing battery production infrastructure. SIBs also demonstrate important advantages in terms of resource sustainability, safety potential, low-temperature performance, fast-charging capability, and cost reduction, particularly for large-scale stationary and grid-level energy storage applications where energy density is less critical. Ongoing research on advanced cathode materials, hard-carbon anodes, Nano structuring strategies, and electrolyte optimization is rapidly improving the electrochemical performance and cycle life of SIBs. Commercially announced sodium-ion cells have already reached energy densities of around 160 Wh/kg, with more recent reports indicating further improvement. Therefore, sodium-ion technology is not expected to fully replace lithium-ion batteries in all applications. Instead, it is likely to complement LIBs by serving cost-sensitive, large-scale, and sustainability-focused energy storage sectors, contributing to a more secure and diversified global battery supply chain.