Freezing lithium batteries may make them safer and bendable

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Liquid  is currently used in commercial lithium

batteries, and, as everyone is now aware, it is highly flammable, causing safety issues with some laptops and other electronic devices. Yang's team explored the idea of using  as a substitute for the  to make all-solid-state lithium batteries. They were interested in using ice-templating to fabricate vertically aligned structures of ceramic solid electrolytes, which provide fast lithium ion pathways and are highly conductive. They cooled the aqueous solution with ceramic particles from the bottom and then let ice grow and push away and concentrate the ceramic particles. They then applied a vacuum to transition the solid ice to a gas, leaving a vertically aligned structure. Finally, they combined this ceramic structure with polymer to provide mechanical support and flexibility to the electrolyte.
"In portable electronic devices, as well as electric vehicles, flexible all-solid-state lithium batteries not only solve the safety issues, but they may also increase battery energy density for transportation and storage. And they show great promise in creating bendable devices," says Yang, whose research group is focused on electrochemical energy storage and conversion and thermal energy management.
Researchers in earlier studies used either randomly dispersed  in  or fiber-like ceramic electrolytes that are not vertically aligned. "We thought that if we combined the vertically aligned structure of the ceramic electrolyte with the polymer electrolyte, we would be able to provide a fast highway for lithium ions and thus enhance the conductivity," says Haowei Zhai, Yang's PhD student and the paper's lead author. "We believe this is the first time anyone has used the ice-templating method to make flexible solid electrolyte, which is nonflammable and nontoxic, in lithium batteries. This opens a new approach to optimize ion conduction for next-generation rechargeable batteries."


Read more at: https://phys.org/news/2017-04-lithium-batteries-safer-bendable.html#jCp