A team of engineers at the University of Illinois (UI) has proposed a polymer-based solid electrolyte that not only repairs itself, but can also be recycled without the need for high temperatures. By using special cross-linked polymers, new electrolytes become harder under heating rather than breaking down. If you look closely, lithium-ion batteries are mostly on fire because of the use of liquid electrolytes – if the battery is severely damaged, it will react with the electrodes.
Brian Jing, a graduate student in materials science and engineering at the University of Illinois, says solid-state polymers or ceramic electrolytes are seen as alternatives, but they tend to melt at high temperatures inside the batteries. One way to solve this problem is to produce rubber-like lithium conductors using cross-linked polymer strands. It has a longer life than a harder solid electrolyte, but it cannot be self-healing and is difficult to recycle.
The UI team developed a way to make cross-linking keys so that they produce an exchange reaction and swap polymer chains between them. This means that the polymer hardens when heated and repairs itself, resulting in less growth of branch-like lithium figs. In addition, polymers can be decomposed without the need for strong acids or high temperatures. Instead, it dissolves in water at room temperature.
The team is working to bring the technology to business.