Kyle Proffitt
February 16, 2026 | Sodium-ion batteries are not quite mainstream, but they are coming, likely to a vehicle or home near you—but maybe not how you think. Described as “the next terawatt-hour technology” by Shirley Meng, sodium promises various advantages relative to lithium, beginning with its global abundance and low cost, and extending to improved temperature performance, safety, power, and longevity. Additionally, the supply chain, unlike that of lithium-ion, does not require a trip through China.
UNIGRID has emerged somewhat quietly as a competitive US-based sodium-ion battery supplier. The company recently announced the initiation of commercial-scale shipments of cells and claims to be the first group outside China to accomplish this feat. They are currently producing batteries at about 200 MWh/year, with plans to reach 1 GWh/year pace within 2026. The company promises to shake up the 12V lead-acid battery industry and to reach new markets in behind-the-meter energy storage.
Battery Power Online spoke with UNIGRID co-founder and CEO Darren Tan to learn about what makes UNIGRID unique in this space and where sodium-ion, and their particular chemical recipe, is making inroads.
A Battery Startup Is Born
UNIGRID is a relatively new company, founded in San Diego, California, in 2021. Tan completed his PhD and post-doctoral work with Shirley Meng (and with PhD co-advisor Zheng Chen) at the University of California, San Diego, but he says much of his work was funded by private industry focused on lithium-ion, work which was not available for him to pursue independently. During the COVID-19 pandemic, he found himself brainstorming with colleagues, including co-founder and CTO Erik Wu, about starting a company. In addition to the intellectual property issues around lithium-ion, the EV market was booming, and competing in this space as a startup seemed unwise. At the same time, they saw a shifting landscape of energy needs as data centers, stationary storage, and home energy backups were increasingly in demand. They saw an opportunity for sodium-ion to fulfill this growing market, realizing that the bulk of fundamental concepts learned in lithium-ion chemistry were translatable to sodium.
Since then, a lot has happened. UNIGRID successfully raised $12M in series A funding in 2024, took another undisclosed investment from LG Technology Ventures the same year, and received a $2.9M California Energy Commission RAMP grant in June of 2025 to build a low-rate initial production line. Now they’re sending 2.2 MWh-loaded shipping containers to ports around the world.
Chromium Cathode is the Driver
“We make a very unique chemistry that no one else in the world does,” Tan said. “We use a sodium chromium oxide-based technology; it is something that we’ve worked on our entire PhD, so we’re very familiar with it.” This sodium chromium oxide (NaCrO2, NCO) cathode technology is a layered transition metal oxide analogous to the NMC common in lithium-ion cells. Just as lithium-ion began with many variants and then narrowed to a smaller set of winners, Tan believes “NCO will be one of the front runners” that persists in sodium-ion chemistry. Beyond the cathode, he says they are using organic NaPF6 electrolyte and hard carbon anode, although they continue to work on optimizing all parts.
The batteries they currently produce are in the range of 125 Wh/kg and 250-270 Wh/L, Tan says, with pricing in the $100/kWh range at the cell level. In the space they are targeting, volumetric energy density matters more than gravimetric, though, and he sees a roadmap to 400 Wh/L, “in a few steps, of course.” With production optimization, he says “we have cost-competitive production with lithium ion phosphate for the cathode level.”
NCO is not a new material, though. It’s been explored academically for the past 30 years. Mostly, it has remained in academia, because severe capacity fade caused by “irreversible structural transitions” occurs with cycling, necessitating strategies such as doping with niobium or ruthenium. UNIGRID has apparently solved this problem. According to Tan, “We found the root cause of its fade; we’ve managed to make 100% pure phase cathode with the right particle sizes,” adding that, “we use single crystals”. Presumably, optimized coatings, binders, and additives help stabilize the NCO. “We expect to get more than 10,000 cycles on this specific material,” he said.
NCO has another advantage. Tan pointed to the 2025 Volta Foundation Battery Report, which includes data for the operating voltage windows—the difference between the upper and lower voltages—of various lithium-ion and sodium-ion chemistries (see page 393 of that report). Most consumer electronics devices are designed to operate using a voltage window (upper minus lower voltage) of around 1.5 V. However, sodium-ion chemistries tend to have windows approaching 2.5 V, which would add complexities and cost to operate electronics efficiently. NCO cells benefit from having a voltage window equivalent to that of NMC.
“Of course, NCO does have downsides too. The biggest downside is that it’s not available in the market … no one wants to make it for us, so we had no choice but to make it ourselves,” Tan said. Thankfully, chromium is not like cobalt; it is an established player in the steel industry, with steady supply lines. It should also be noted that this chromium is Cr3+/Cr4+, not the toxic, hexavalent chromium made famous by Erin Brockovich.
Inherent Safety: NCO Again
Tan says it is a myth that all sodium-ion batteries are automatically safe. UNIGRID’s batteries are safer, he says, because of the NCO cathode. He explained that the cathode is often responsible for thermal runaway events; in an unstable state, caused by overcharging or heating, it will release its energy. “Usually, it also releases oxygen, and it releases heat,” Tan said, and that truly creates a problem. With fuel (such as organic electrolyte), a fire can easily start and get out of hand quickly. However, NCO does not easily give up its oxygen. Testing NMC and LFP lithium-ion variants alongside their NCO cells, oxygen and heat release is triggered at 150, 200-250, and 500-550 °C, respectively, Tan says, pointing out that if your home is over 500 °C (nearing 1000 °F), you have bigger problems. “We pass every possible safety abuse test, because when the internal short is triggered, the intrinsic battery energy gets released, yes, but the cathode doesn’t decompose to release oxygen and heat, so severe thermal runaway is avoided,” Tan explained. He said the pressure and energy release may manifest as smoke or fumes, but “that particular battery doesn’t propagate to its neighbor.”
Use Case 1: 12V Battery Replacement
Tan says their batteries will serve two primary markets. “The immediate beachhead market is the 12-volt starter battery space because that’s the classic kind of [business] story; it’s a well-established $50 billion market dominated by a 100-year-old technology, and it’s ready for disruption,” Tan said.
He provided a convincing argument that sodium-ion will replace lead-acid batteries. “It’s probably the last battery your vehicle will need,” he said. It gets better, because it should actually cost less up front, not only calculated over usage lifetime. Asked about the cost to replace a 12V lead-acid battery with sodium-ion the next time it’s needed, Tan said he is “fairly confident that you can get the exact same thing for cheaper than the lead acid that you pay for right now.” He explained that this is possible in part because of an unforeseen but huge advantage of sodium-ion. The biggest pain point for lead-acid, he says, is for warranty issues and shelf life. Lead-acid batteries suffer self-discharge, and if they aren’t recharged in time (about a 3-month window), they can actually discharge past a point of return. This means any disruption in the supply chain, changes in tariffs or policy that causes an extra month’s delay, could ruin an entire batch. In contrast, for sodium-ion, “we really don’t care how long it sits… not only is your self-discharge rate lower—you lose maybe 1 or 2% a month—it can sit at zero percent indefinitely,” Tan said. “This is very attractive for commercial fleets… for military vehicles, for example, where they are left in storage for years.” That’s unique to sodium-ion; lithium-ion also does not like to sit at 0%. With this feature, sodium-ion creates a margin advantage as the expected losses of lead-acid don’t have to be calculated into the prices, and this savings can be passed on to the customer.
Additionally, sodium-ion has an advantage of reliably starting your vehicle at -40 °C. They expect these 12V drop-in replacement sodium-ion batteries to be used in cars, trucks, motorcycles, forklifts, golf carts, and more. One more advantage—while lead acid battery recycling is an effective win in the sustainability picture, it has come under fire recently for poisoning the people involved. Sodium-ion promises more benign materials, although a healthy circular economy has yet to be established.
Use Case 2: Behind the Meter
“The second and I think the bigger opportunity is the behind-the-meter storage space,” Tan said. “We think that behind the meter, there is some adoption of LFP, but the dominance will come with sodium-ion.” This includes anything that is privately owned: factory, home, hospital, apartment complex, etc. Behind the meter, he said, “price is no longer the biggest decision-making factor, because now you’re putting batteries near where people live, work, and play; safety becomes so important.” He continued, saying, “we can put batteries in places where lithium-ion is not even allowed, where fire marshals would reject.” Additionally, the longevity of their batteries changes the value proposition such that return on investment can be calculated over decades. “When I install solar, and I get a warranty of 25 years, I would like my battery to also last 25 years,” he said, and he foresees their batteries fulfilling the need. He provided a hypothetical scenario where an individual could lease their batteries at a very low daily cost, avoiding the hesitancy of making a large purchase up front. Meanwhile, with this model, if anything happened to the battery, it would be on UNIGRID to replace it.
Energy Security
Given the opportunity, Tan provided a bit of historical review of societal advantages as we established water storage and security using water towers and food storage with refrigeration; he sees distributed energy storage, mediated by batteries, as a new frontier that will help us accomplish greater energy security and flexibility. The idea is that, increasingly, there will be more of this behind-the-meter storage, which will enable resilience during power outages, improve alignment between renewable energy demand and usage, reduce peak loads, and improve the actual efficient utilization of the electricity produced. Tan explained that the energy companies have to plan for that absolute peak of usage, but it makes more sense and costs less to store some of the excess energy when it’s not needed. Because large-scale grid upgrades are capital-intensive and slow to deploy, distributed storage can act as a set of shock absorbers within the system, easing strain on the aging American infrastructure. Tan brought the analogy full circle: “you need a ‘water tower’ for electricity,” saying this ‘tower’ could be in your home or in your community.
Lean on the Foundries
UNIGRID is taking a somewhat unique approach to manufacture, and this may help to differentiate them and save them from the fate of Natron. “We adopt a 100% foundry model, so we don’t have to fight any yield problems, production ramp problems, or factory operational problems,” Tan explained. “We lease and award service contracts to foundries with full production ongoing already.” In contrast, Natron was fully integrated from precursors through stationary storage systems and trying to operate a gigafactory, he said, indicating it was just too much. Tan says knowing what they should not do—build and run a gigafactory in particular—is more important for a startup right now than just knowing what they should do.
He provided more of the logic of their business model. “We are making and selling batteries not at the cheapest point … our goal is not to drive the race to the bottom.” Instead, “we want to drive value propositions where lithium-ion cannot serve … if a customer is very happy using LFP, we want them to continue using LFP … if they have a problem with safety, longevity, temperature performance, or power, that’s where we come in,” he said.
On the Horizon
In addition to ramping production, UNIGRID is pursuing other advances, including alloy anodes and high capacity hard carbon. Tin has been reported as an alloy being pursued, and collaborative research is active there, but Tan says that tin prices have increased significantly in the past few years. It is no longer an economical choice, but other alloys are options.
Improving energy density is of course desirable. For sodium-ion, “the state of layered oxides today I’d say is like lithium ion was in the 2000s,” Tan said. He continued, saying that NCO is “only using half of its possible capacity, and like lithium ion, it will also improve over the next few years.” He says there is a foreseeable path by which these layered oxides can beat LFP in energy density. Their 12V batteries are “already in a few hundred vehicles outside the US,” and Tan expects to put them in vehicles in the US very soon. He is hopeful to see their batteries installed in American homes this year as well.
