A study found that sodium-ion batteries used in electric vehicles and large-scale energy storage systems (ESS) in China showed production quality and performance on par with Tesla's lithium-ion batteries.
Researchers at RWTH Aachen University in Germany published on the 29th in the international journal Cell Reports Physical Science the results of their analysis of a commercial sodium-ion battery made by the Chinese battery corporations Hina.
Sodium-ion batteries operate on a principle similar to lithium-ion batteries but use sodium instead of lithium as the key raw material. Sodium, an element also found in salt, is far more abundant and easier to procure than lithium. In the long term, it can reduce raw material expense and supply chain risks.
In this study, the team analyzed 120 Hina battery cells (the basic unit that makes up a battery) using electrochemical impedance spectroscopy, a non-destructive testing method. Impedance spectroscopy examines the internal state by measuring electrical responses without opening or damaging the battery. The batteries were tested under various temperature conditions from minus 20 degrees to 45 degrees, and X-ray imaging and cell teardown analyses were also conducted.
The researchers said Hina batteries showed small quality variations between cells and could deliver high output stably. In particular, they featured a "tabless" design that reduces resistance when current flows and spreads heat evenly. The tabless structure is known as one of the core designs of Tesla's batteries.
However, sodium-ion batteries had lower energy density than top-tier lithium-ion batteries. Energy density refers to how much energy can be stored for the same size or weight and is a key factor that determines an EV's driving range. Therefore, sodium-ion batteries are more likely to be suitable for short-range vehicles, commercial vehicles, or stationary energy storage systems than for passenger EVs that must travel long distances on a single charge.
Sodium-ion batteries also showed reduced charging performance at low temperatures. In some regions of the battery electrodes, copper content was higher than expected and distributed unevenly.
Moritz Schütte, a researcher at RWTH Aachen University in Germany, said, "To charge efficiently in subzero environments, a separate thermal management system or operational strategy is necessary," and added, "Further research is needed to examine what role the copper found in the electrodes plays in battery performance and aging."
The researchers added, "Going forward, research is needed to improve the low-temperature charging performance of sodium-ion batteries and to optimize material combinations," and noted, "Improving the composition of the electrolyte and using a carbon material anode made of 'hard carbon' are promising directions."
References
Cell Reports Physical Science (2026), DOI: 10.1016/j.xcrp.2026.103323