Lagos — Sodium-ion and lithium-ion batteries share the same electrochemical principles, with sodium replacing lithium. While different cathodes, anodes, and electrolytes are required to accommodate this substitution, the overall chemical makeup remains similar across both technologies.
The most significant difference lies in the cathode. However, sodium-based alternatives to lithium-ion’s NMC (Nickel Manganese Cobalt) and LFP (Lithium Iron Phosphate) are actively being developed by key players, according to the new IDTechEx report, “Sodium-ion Batteries 2025-2035: Technology, Players, Markets, and Forecasts.” The three main types of sodium-ion cathodes in development are transition metal oxides (similar to NMC), polyanions (similar to LFP), and Prussian blue analogs (unique to sodium-ion).
Transition metal oxides and Prussian blue analogs are particularly promising due to their low cost and avoidance of rare earth elements. Transition metal oxides, typically composed of sodium, oxygen, nickel, iron, and manganese, exclude cobalt, addressing sustainability concerns that have plagued lithium-ion batteries. Prussian blue analogs, with their rhombohedral structure, consist solely of sodium, iron, carbon, and nitrogen, marking them as unique to sodium-ion technology.
On the anode and electrolyte front, sodium-ion batteries are largely similar to lithium-ion. Hard carbon anodes, used in earlier lithium-ion generations, are the preferred choice since sodium-ions are too large to intercalate into graphite. Electrolytes consist of similar salts and solvents, with sodium replacing lithium—such as NaPF6 in a carbonate solvent.
Comparing the different performance characteristics, one can see the general pros and cons of each battery chemistry. The energy density for sodium-ion batteries is still lower than that of high-energy lithium-ion cells, which use nickel, but they are approaching the energy density of high-power lithium iron phosphate (LFP) cells. The cycle life of cells is reasonable in some configurations, but one of the interesting elements not shown in the image is that sodium-ion batteries can have quite high-power characteristics with reports of ~1000 W/kg, which is higher than NMC (~340-420 W/kg) and LFP (~175-425 W/kg) cells. They also exhibit better low-temperature performance.
Cost competitiveness in a changing market
A primary advantage of sodium-ion batteries is their potential for lower costs compared to lithium-ion technologies. At scale, a sodium-ion battery featuring a layered metal oxide cathode and a hard carbon anode is expected to have material costs approximately 25-30% lower than a lithium iron phosphate (LFP) battery. This cost reduction is primarily driven by the substitution of lithium and copper with more affordable sodium and aluminum, which offers around a 12% reduction in cost, largely due to the use of aluminum as the current collector.
However, the cost structure is influenced by several factors. The main cost drivers of any battery are the electrode materials, with hard carbon emerging as the leading anode material for sodium-ion batteries. While hard carbon offers a cost advantage over graphite, it has a lower density, meaning more electrolyte is required for the same active material, adding to cost and mass. Moreover, hard carbon tends to be more expensive than natural graphite, and certain variants exhibit lower performance.
The future of sodium-ion batteries and their ability to undercut lithium-ion on price remains an area of significant debate. While the cost of lithium-ion batteries continues to decline, the timeline for when sodium-ion technology could match or beat these prices is still speculative. IDTechEx finds that engineering breakthroughs, rather than simply scaling production, will be key in driving down sodium-ion costs.
If lithium prices remain near historic lows, sodium-ion batteries face a narrower path to becoming cost-competitive in the next decade. However, with continued engineering advances, sodium-ion could emerge as a complementary technology, offering value in specific applications where cost reduction and material availability are paramount.
The IDTechEx report, “Sodium-ion Batteries 2025-2035: Technology, Players, Markets, and Forecasts”, explores the cost dynamics, technology advancements, and the realistic roadmap for sodium-ion’s place in the future battery market.
