researcher in China has announced a radical sodium metal battery (SMB) design that can be fully charged in just four minutes and will retain its capacity for years of use.
SMBs are a form of ultrafast-charging, stable batteries that scientists say could one day be a cheaper alternative to today’s lithium-ion (Li-ion) batteries, which rely on geographically concentrated metals and catch fire easily. SMBs also differ from sodium-ion (Na-ion) batteries in that they use a metallic sodium anode rather than a graphite or hard carbon anode.
However, SMBs remain largely theoretical because they are prone to a type of degradation known as dendrite formation. This occurs when sodium ions passing through the electrode are deposited on the highly reactive, pure-metal sodium anode in spiky, stalagmite-like structures. Over time, this forms a bridge between the cathode and anode, causing the battery to short-circuit.
Dendrite formation is particularly common in sodium batteries because sodium is a highly reactive metal. When charge moves through a Li-ion, Na-ion, or sodium metal battery, the anode always reacts with the electrolyte to form an oxide layer known as SEI. It is usually 10 to 50 nanometers thick – approximately as widespread as a tiny virus – But generally harmless. But with sodium, SEI often breaks down, forming bulges that attract sodium ions, which pile up in the dendrites.
Now, researchers say they have solved this issue by using a tough, semi-solid gel electrolyte – called Sn-FB CuSe – which strengthens the battery against punctures and provides a semi-solid internal structure that prevents dendrites from forming. They outlined their findings in a study published May 21 in the journal nano-micro paper.
To confirm the longevity of this approach, scientists charged and discharged the battery for more than 6,000 hours without short-circuiting the dendrites. They also noted that when they charged the battery from zero to 100% capacity in just four minutes, it retained an electrical charge, measured in milliampere-hours per gram (mAh g).-1), of 80.1. This is equivalent to about half of that held in Li-ion batteries.
When charged at a slightly slower rate from zero to 100% in 20 minutes, the battery retains 90% of its charge capacity over 2,000 cycles – that’s the same. Theoretical Limits for Li-ion BatteriesScientists said in the study. This slower speed reduced costs and improved safety.
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This is noteworthy because scientists have achieved this feat in the new battery, while it can be charged faster than Li-ion batteries. This is relevant as charging speed remains a critical point for battery deployment in electric vehicles (EVs). The fastest charging EV today is the BYD Denza, which Chinese automaker says Can go from 10-70% in just five minutes. But this requires a highly specialized, 1MW proprietary charger.
Most EVs charge very slowly – Tesla representatives say Its Model 3 can recharge from 10-70% in about 15 minutes using Tesla’s own 250-kilowatt flash charger, but representatives of the EV routing platform zapmap says The same vehicle will take 90 minutes to get 80% charged on a 50kW charger.
In fact, most batteries used for modern technologies like smartphones and EVs are Li-ion. However, Li-ion batteries are expensive to produce because they contain difficult-to-obtain metals such as lithium and cobalt, and they are prone to fire.
Increasingly, battery manufacturers are looking to bring Na-ion batteries to commercial scale because they are affordable and safe. However, they are heavier and larger than Li-on batteries.
SMBs are the focus of intense research because they theoretically combine the best of both types of batteries. Because SMBs use a sodium anode, rather than Na-ion batteries which use graphite or hard carbon anodes, they are lighter and cheaper to produce and therefore far more comparable to Li-ion in terms of size and weight. They are also safer because they work using sodium ions, which are heavy and cannot flow through the battery wall fast enough to cause thermal runaway. This is a self-sustaining chain reaction that causes the battery to ignite when it is damaged.
If the issues of dendrite formation and stability at low temperatures can be solved, replicated and scaled, SMBs could reshape the economics of battery deployment over the next decade, the scientists said.
Scientists believe that SMBs could be excellent alternatives to EVs in public transportation or commuter cars, because although their range is shorter than Na-ion and Li-ion vehicles, they charge faster. However, they won’t be available in vehicles or small devices like consumer electronics for some time.
This is because devices like smartphones are subject to drastic temperature changes that affect the internal chemistry of batteries that rely on gel electrolytes. Research must be repeated before manufacturers feel comfortable using pure sodium metal in place of the well-understood graphite configuration.
Zhang, Y., Pan, L., Leong, C.W., Qi, X., Huang, X., Cai, X., Cao, M., Gao, M., Zhang, H., Sha, D., Zhou, Y., and Sun, Z. (2026). Dual interlock mediators enable single-ion-conducting quasi-solid-state electrolytes for ultrafast-charging long-lasting sodium metal batteries. nano-micro paper, 18(1). https://doi.org/10.1007/s40820-026-02236-2