Solid-state, semi-solid, sodium: battery labels outrun the test data

The award puts safety first

The Natural Sciences and Engineering Research Council of Canada announced the award, CBC reported on 3 November. The council said her "world-leading discoveries have transformed the science of electrochemical energy storage" and laid a foundation for safer, more efficient cells. Nazar told CBC she was "deeply honoured" and "quite honestly humbled" to join the list of past winners.

That work matters to anyone buying an electric vehicle, a warehouse robot or a grid battery, because flammable liquid electrolytes are the failure mode regulators watch. What buyers still lack is a way to compare designs. Xpeng has not said whether the batteries in its Iron robot are all-solid-state, and Svolt has not published the test conditions behind its fast-charge figure.

Her case for solid state is straightforward. Liquid electrolytes are flammable and can burst into flames, she said, while a solid version offers "much better safety".

She also claims a wider operating temperature range, naming drones flying at high altitude, Arctic deployment and military use. Higher energy density is the third selling point, achieved by packing cells more effectively in a configuration she called bipolar stacking. None of those claims is new. What is new is how fast the vocabulary has moved into shipping products.

Why the label matters

Svolt Energy's first mass-produced batch of 100-kWh Dragon Armor semi-solid fast-charging packs rolled off the line in Changzhou, Jiangsu province. The company announced the milestone on 26 October.

On 28 October, Xpeng vice president Gu Jie said solid-state batteries for the Iron humanoid robot had begun rolling off the production line in small batches. The robot itself is still pre-production. Xpeng's disclosure used the term "solid-state battery" without saying whether it means the all-solid-state technology the company announced in November 2025.

The distinction is not academic. Svolt defines semi-solid cells as using both liquid and solid electrolytes, while all-solid-state cells rely entirely on solid electrolytes. A buyer comparing the two press releases is comparing two different things.

Xpeng's update also came without an energy density figure or a production volume.

Sodium takes a different route

Elsewhere the chemistry is moving away from lithium altogether. A team led by Professor Chan-Jin Park at Chonnam National University in South Korea developed a polymerisable deep eutectic solvent electrolyte for sodium metal batteries.

Park's group says the electrolyte is non-flammable and leak-resistant, and that the polymerised matrix holds up when the cell is folded or cut. In full-cell testing the battery reached an initial discharge capacity of 110.2 mAh g-1 at 0.1 C with nearly 99% coulombic efficiency. It kept 90.4% of its capacity after 1,000 cycles at 2 C. A pouch-cell version kept an LED lit while being folded and cut. The study appeared in Energy Storage Materials.

Park framed the work as a route to cheaper storage, not a premium product. He cited grid storage, backup power and low-cost rechargeables.

What factories claim

The company says the pack supports 900-volt, 6C charging and adds 500 km of range in 12 minutes. It says cycle life exceeds 3,000 cycles, for a theoretical lifetime distance of more than 1 million km.

Chairman and CEO Yang Hongxin said semi-solid batteries "will become a mainstream technology over the long term," not a stepping stone. Svolt said in May that all-solid-state cells were still a long way from mass production, and predicted 2026 would mark the start of widespread semi-solid adoption. Xpeng is on a different clock. It still targets mass production of Iron by the end of 2026, with commercial deployment in stores and other settings from 2027.

Definitions and what comes next

The U.S. Department of Energy draws the line simply. Solid-state batteries use solid electrolyte solutions and do not need a separate separator, which makes them less prone to leakage from damage or swelling in hot temperatures. The department also says next-generation designs, including solid-state and flow batteries, may improve performance and safety while cutting use of critical materials.

Nazar has moved on to another chemistry herself. She is working on aqueous batteries, which use water as an electrolyte, with the Department of Energy out of a hub at Stanford.

Svolt says it will keep advancing semi-solid cells first, followed by all-solid-state.