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What is a sodium-ion battery?
A sodium-ion battery is a rechargeable battery that moves sodium ions between two electrodes. It works on much the same “rocking-chair” principle as lithium-ion, but uses a different family of electrode materials and does not need lithium.
The short version
During charging, sodium ions leave the positive electrode, travel through the electrolyte and are stored in the negative electrode. Discharging reverses that journey and pushes electrons through the device you are powering. A separator keeps the electrodes apart while still allowing ions to move.
“Sodium-ion” is a family, not one fixed recipe. Commercial developers use layered-oxide, polyanionic or Prussian-blue-analogue cathodes, usually paired with a hard-carbon anode. Those choices alter energy density, cost, temperature behaviour and material needs.
Why sodium instead of lithium?
Sodium is widely available and sodium-ion cells can use aluminium for both current collectors. They can also avoid lithium, cobalt and natural graphite, depending on the cathode. That may diversify material supply, but it does not make every sodium cell free of critical minerals: some layered oxides still use nickel or manganese.
The trade-off is lower energy density. The IEA put leading 2026 sodium-ion cells at about 175 Wh/kg, below the leading figures it cited for LFP and NMC. That matters greatly in a long-range car and much less in a garage battery.
Where it fits
The strongest near-term cases are stationary storage, cold-climate vehicles, starter batteries and applications now served by lead-acid. Sodium-ion is not a universal lithium replacement. Mature LFP remains difficult to beat on supply chain, price and field history, while NMC carries more energy where weight matters most.
Questions answered
Is it a saltwater battery?
No. Some older aqueous batteries were marketed as saltwater batteries, but most modern sodium-ion cells use non-aqueous electrolytes.
Does it contain metallic sodium?
A conventional sodium-ion cell stores sodium within electrode materials; it is not the same as a high-temperature sodium–sulphur battery containing molten sodium.
Sources
- Sodium-ion battery momentum grows, but challenges remain — International Energy Agency, 17 February 2026.
- Strong performance — Faradion, checked 10 November 2026.
Sources last checked 10 November 2026. Product availability can change.