Batteries with anodes made of lithium metal promise electric vehicles (EVs) that go twice as far between charges as cars powered by today’s batteries, which rely on graphite anodes. But lithium-metal anodes have been held back because, over the course of charge cycles, they sprout tiny spikes called dendrites that can pierce an insulating film and cause dangerous short circuits.
Researchers have now found a way to keep those pesky dendrites from forming: soaking lithium foils for 20 min in a 1% water etching solution (Watt 2026, DOI: 10.1007/s44503-026-00006-0). Just like a warm bath soothes and settles, this chemical bath stabilizes the lithium-metal foil, says Jiaxing Huang, a materials scientist at Westlake University. The treatment could be a “simple drop-in solution” for the production of lithium-metal batteries, he says.
Dendrites form because films of lithium, like most metals, tend to be polycrystalline, composed of tiny crystal grains with random orientations. “The different facets have different atomic density and different chemical reactivity,” Huang explains. So as the battery charges and discharges, lithium deposits and collects faster at the more reactive sites, leading to dendrites at those locations.
This lithium plating would be uniform on a single crystal of lithium, but growing the metal in that form is expensive and cumbersome. So Huang and his colleagues turned to the next best thing—they converted the polycrystalline surface to one that is quasicrystalline, with all the crystal grains having the same orientation.
The inspiration came from Huang’s decade-old work on controlling the shape of metal nanocrystals. “A common trick to do beautiful shape control,” he says, is to etch less-stable crystal facets so they lose some atoms and rearrange into a more stable crystal form. “The principle is not super fancy,” he says.
The researchers applied this principle to lithium-metal batteries. “Water is a fantastic etchant for lithium,” he says. But lithium reacts explosively with pure water. So they added 1% water to dimethyl sulfoxide and immersed a lithium-foil anode in the solution.
The solution corrodes the two less-stable facets on the surface, and the underlying lithium atoms rearrange until all the facets eventually take on the stable (110) crystal orientation. Lithium now plates much more uniformly. Coin-sized lithium iron phosphate batteries that the researchers made with the washed lithium-metal anodes worked for over 2,000 charge cycles without failing because of dendrite formation.
Younan Xia, a nanomaterials researcher at Johns Hopkins University, says this is “a brilliant idea to effectively address a major issue in lithium-based batteries.” The technique will need to work on electrode areas hundreds or thousands of times larger to be used practically, he says. “If the treatment can be further shortened to minimize the production cost, I think this technology will find immediate use in the commercial process.”