Sodium-ion batteries trade some energy density for abundant raw materials and potentially safer, lower-cost stationary storage. In 2026, CATL signed a three-year, 60 GWh sodium-ion supply agreement and Peak Energy advanced plans for US manufacturing. Here is why the chemistry could challenge lithium on the grid, and what still has to prove out.
Most large batteries supporting the power grid use lithium-ion chemistry, increasingly lithium iron phosphate, which avoids nickel and cobalt but still depends on lithium processing and a supply chain concentrated in China. Lithium-ion works well, yet project developers must manage price exposure, thermal-runaway risk, and supply concentration.
Sodium-ion offers another route. Sodium is abundant and is one of the elements in table salt, although a sodium-ion cell is not literally made from household salt. The first US grid-scale sodium-ion system was delivered in 2025; in 2026, much larger manufacturing commitments and supply agreements began moving the chemistry toward commercial scale.
The timing is not an accident. Grid-battery demand is exploding as solar and wind and power-hungry data centres reshape the electricity system, and utilities are nervous about leaning the entire build-out on one flammable chemistry sourced through one country. A cheaper, safer, home-grown option arriving right now lands on very fertile ground.
Here is what happened
America's first grid-scale test began in 2025. Colorado-based Peak Energy delivered a US grid-scale sodium-ion system for a utility trial involving nine utilities. In 2026, the company selected Sacramento for a proposed 4 GWh factory, targeting production in 2027. Cooling and fire-protection advantages are company claims that still need long-duration field validation.
A 60 GWh order changed the scale of the conversation. In April 2026, CATL and HyperStrong signed a three-year sodium-ion energy-storage agreement covering 60 GWh. CATL says its first sodium-ion storage-system deliveries will begin in China in September 2026, with cumulative shipments targeted to reach 1 GWh by year-end and international deliveries scheduled for 2027.
Some chemistries reduce critical-material exposure. Sodium-ion eliminates lithium, and CATL's NFPP-based system is designed to reduce reliance on other constrained battery materials. Sodium-ion formulations vary, however, so claims about nickel, manganese, or other inputs should be tied to the specific cell chemistry.
China is out front, and betting big. CATL, the world's largest battery maker, is not dabbling: it has declared sodium-ion mainstream-ready and lined up tens of gigawatt-hours of orders. That matters because CATL's scale is what dragged lithium prices down over the last decade, and it is now aiming the same machine at sodium.
How it works
Same idea, cheaper element. A sodium-ion battery works like a lithium one, shuttling charged particles between two electrodes as it charges and discharges, but swaps lithium for sodium. Sodium ions are bigger and heavier, so the battery stores a bit less energy for its weight, which is why it lost the race for phones and cars.
Weight does not matter on the ground. A grid battery sits in a field; it does not have to be light. There, sodium's downside fades and its strengths, low cost, abundant materials, and safety, move to the front.
Potentially safer thermal behaviour. CATL and Peak report lower heat generation and greater thermal stability than conventional lithium-ion systems, which could reduce cooling and fire-protection requirements. Sodium-ion does not eliminate battery risk; independent, long-duration field data and system-level safety testing remain essential.
Why it matters
It targets the economics utilities care about. Installed storage cost depends on more than the cell: cycle life, efficiency, cooling, fire protection, land, financing, and maintenance all matter. If sodium-ion reduces both cell and balance-of-plant costs while meeting performance guarantees, more four-to-eight-hour projects could become economical.
It diversifies the supply chain. Abundant sodium reduces dependence on lithium extraction and processing. Manufacturing expertise and upstream materials are still concentrated, particularly in China, so the chemistry broadens the resource base without automatically creating a domestic supply chain.
It targets the everyday grid job. This is not the multi-day, "days not hours" battery; that is a separate, longer-duration race. Sodium-ion goes straight at the bread-and-butter four-to-eight-hour storage that smooths each day of solar and wind, the biggest single slice of the market.
Improved safety could change where systems are built. Lower thermal-runaway risk may ease permitting, insurance, and siting near substations or populated areas. Those benefits must be demonstrated at system scale rather than assumed from cell chemistry alone.
The honest catch
Sodium-ion is real and scaling, but it is early in the US and not a free win.
Less energy per unit. Sodium-ion still stores less energy for its size than lithium, so it needs more space, fine in a field, a drawback where land is tight.
China holds the manufacturing lead. CATL has announced large production investments and delivery targets. US companies such as Peak Energy must prove that domestic factories can deliver competitive costs, cycle life, efficiency, and warranty performance at scale.
Trial, not track record. Peak Energy's grid system is in a utility trial. The numbers that matter, real cost per kilowatt-hour, cycle life, and hot-weather performance over years, are still being gathered.
EDITOR'S TAKE
The near-term battery contest is not only about exotic chemistries that store power for days. It is also about the ordinary four-to-eight-hour systems utilities can deploy repeatedly. Sodium-ion is emerging as a credible challenger because it uses abundant sodium and may offer thermal and cost advantages for stationary storage, where weight matters less. The commercial evidence is now larger than a laboratory prototype: CATL has signed a 60 GWh agreement, while Peak Energy is planning US manufacturing. Watch delivered system cost, cycle life, safety data, factory execution, and whether utilities specify sodium-ion in competitive procurements. Those numbers, not a single headline cell price, will show whether lithium faces a durable grid competitor.
Quick questions
Is a sodium-ion battery just a worse lithium battery?
Not simply. Sodium-ion generally stores less energy for a given weight or volume, which can disadvantage mobile applications. For stationary storage, weight matters less, while raw-material abundance, temperature performance, safety, cycle life, and total installed cost matter more. Whether it is better for the grid will be decided by field data and project economics, not one performance metric.
Is this the same as the iron-air, multi-day battery?
No, and the difference matters. Iron-air batteries are built to discharge slowly for days, to cover long, still, cloudy stretches. Sodium-ion is a fast, everyday battery aimed at the four-to-eight-hour job of smoothing each daily cycle of solar and wind, the same role most lithium grid batteries play now, but cheaper and safer. A future grid will likely use both: sodium-ion for the daily swing, something like iron-air for the rare multi-day gap.
When will this actually be on the grid at scale?
In China, industrial scaling is beginning: CATL's 60 GWh agreement covers three years, and the company targets its first storage-system deliveries for September 2026. In the US, Peak's demonstration system was delivered in 2025 and its proposed Sacramento factory targets 2027 production. Significant deployment is plausible within the next few years, but it depends on factory execution and bankable operating data.
Sources
Peak Energy company milestones and US grid-scale deployment (Peak Energy): the 2025 system delivery and 2026 Sacramento factory announcement.
CATL and HyperStrong sign a 60 GWh sodium-ion agreement (CATL): the primary announcement of the three-year supply agreement.
CATL debuts its field-validated sodium-ion storage system (CATL): manufacturing capacity and 2026-27 delivery targets.
Sodium-ion prototypes now approaching 200 Wh/kg (pv magazine): on the chemistry's improving energy density.
Technology Strategy Assessment: Sodium Batteries (US Department of Energy): independent background on sodium-ion advantages, limitations, and research needs.
Frontier Signal explains frontier technology in plain English. Company and agency figures should be independently verified. This is general information, not investment advice.
