A spray-on coating developed by Professor Junjie Niu, materials science & engineering, and his research team has improved the energy density of lithium-metal batteries by 20 to 30 percent –while also reducing the fire risk that has long limited their commercial use. The results, recently published in the journal Small, could accelerate the development of next-generation rechargeable batteries.
“The results surpassed our expectations,” Niu said. “Our coating offers a dual benefit –better performance and better safety.”
Niu’s research focuses on lithium-metal (LM) batteries, a newer type of lithium-based battery that replaces graphite electrodes with solid lithium. LM batteries can hold significantly more energy than traditional lithium-ion batteries, making them attractive for high-demand needs, such as electric vehicles or energy storage for the grid, Niu said.
“With the current li-ion batteries, you can drive, let’s say, 300 miles on a charge,” he said. “With a LM battery, you can double the energy density – maybe 500 to 600 miles. That’s even better than a gas-powered vehicle!”
But there’s a catch: LM batteries are notoriously unstable. The problem stems from dendrites –needle-like structures of lithium that form during charging. Dendrites can pierce the battery’s electrolyte, causing short circuits and even fires.
To address this, Niu’s team developed a spray-on coating that combines MXene compounds –known for high electrical conductivity – with a large-molecule polymer that stabilizes the battery surface. The polymer helps prevent dendrite formation, while the MXene improves charge transport.
The innovation targets a key challenge that has stalled commercial rollout of lithium-metal batteries, despite their promise and the considerable industry investment.
The research was completed with a grant from the National Science Foundation.