Lithium-ion batteries could become self-healing
Engineers at the University of Illinois have developed an electrolyte that could help manufacturers produce recyclable, self-healing commercial batteries.
In a study published in the Journal of the American Chemical Society, the researchers said that they have created a solid polymer-based electrolyte that can self-heal after damage—and the material can also be recycled without the use of harsh chemicals or high temperatures.
In their paper, the experts wrote that their invention came to be as a response to the push to replace the liquid electrolytes in lithium-ion batteries with solid materials such as ceramics or polymers. This addresses issue related to batteries developing dendrites or branchlike structures of solid lithium after going through multiple cycles of charge and discharge.
Dendrites reduce battery life, cause hotspots and electrical shorts, and sometimes grow large enough to puncture the internal parts of the battery, causing explosive chemical reactions between the electrodes and electrolyte liquids.
“Solid ion-conducting polymers are one option for developing non-liquid electrolytes,” Brian Jing, one of the study’s co-authors, said in a media statement. “But the high-temperature conditions inside a battery can melt most polymers, again resulting in dendrites and failure.”
To address this issue, the researchers developed a network polymer electrolyte in which the cross-linking point can undergo exchange reactions and swap polymer strands. In contrast to linear polymers, these networks actually get stiffer upon heating, which can potentially minimize the dendrite problem. Additionally, they can be easily broken down and resolidified into a networked structure after damage, making them recyclable, and they restore conductivity after being damaged because they are self-healing.
“Most polymers require strong acids and high temperatures to break down,” said Christopher Evans, the lead author for the paper. “Our material dissolves in water at room temperature, making it a very energy-efficient and environmentally friendly process.”