Gel-coated battery can stop mobile phones from exploding or setting fire to themselves

Numerous modern technologies use one or more lithium-ion batteries. These cells can generate large amounts of power together. The batteries are fragile and can be damaged by other cells. This could cause a chain reaction which releases the battery's power in dangerous ways. Faulty batteries have led to electric cars, smartphones, and electric scooters setting themselves ablaze.

A new material could be added to lithium-ion batteries to prevent fires.

It is advantageous for the individual lithium-ion batteries within a battery that each conducts heat with its neighboring cells, in order to help cool any potential thermal runaway. It is better to isolate the hot, dangerously heated cell once it reaches a tipping point so that the rising heat doesn't damage other cells.

Wu Hui from Tsinghua University, Beijing and his collaborators have developed a material that can wrap individual cells and conduct heat well to maintain thermal equilibrium. The material traps water and evaporates at a temperature that can be adjusted to suit different batteries. Instead of insulating the cells from one another, it insulates them. This material is a hydrogel that has tiny ceramic particles embedded in it. It can be molded into any shape you like to fit different battery designs.

Aerogels were used to isolate cells in battery cells in the past, but they are not permanent insulators and expensive to make. Researchers claim that the new hydrogel material can be made cheaply and that industry is already working to improve safety features in new batteries.

Wu believes that thermal runaway is an important safety problem to address. He says, "We are very interested in the battery safety situation, and considering electric vehicles grow so quickly, the problem is very urgent and important." "In China, we have had at least 7000 battery fires in a year. This number is increasing rapidly." This is a serious situation, especially when you consider that this number could be doubled in a global market.

Journal reference: ACS Nano, DOI: 10.1021/acsnano.2c02557