Looking to overcome issues associated with the liquid electrolyte used in commercial lithium batteries, assistant professor Yuan Yang’s team explored using a solid electrolyte. In particular, the team was interested in using ice-templating to create vertically aligned structures of ceramic solid electrolytes. These, said the team, would provide fast lithium ion pathways and be highly conductive.
To create these, an aqueous solution with ceramic particles was cooled from the bottom and ice allowed to grow. A vacuum was then applied to transition the solid ice to a gas, leaving a vertically aligned structure. This ceramic structure was then combined with a polymer to provide mechanical support and flexibility.
“Flexible solid state lithium batteries not only solve the safety issues, but may also increase battery energy density for transportation and storage. And they show great promise in creating bendable devices,” said Yang.
The team says its approach could, in principle, improve the energy density of batteries. By using the solid electrolyte, the lithium battery’s graphite anode could be replaced by lithium metal, boosting specific energy by up to 70%.
Researcher Haowei Zhai added: “We believe this is the first time anyone has used the ice-templating method to make a flexible solid electrolyte in lithium batteries. This opens a new approach to optimise ion conduction for next-generation rechargeable batteries.”