A Korean team of researchers from UNIST and Seoul National University have discovered a new way to develop all-solid-state lithium batteries without running a risk of conflagration or explosion.
The new process involves melting a battery’s solid electrolyte and coating the same around the electrodes.
Lithium-ion batteries, currently in production, make use of an organic liquid electrolyte which has a characteristic of easily getting gasified or burnt. This brings all-solid-sate lithium batteries to the fore as they are non-flammable.
Nevertheless, the powder type of solid electrolyte does not permeate, compared to the liquid electrolyte. If the contact between electrolytes and electrode active materials is not active, it would be more difficult to move lithium-ion to the electrode. Furthermore, it will not be simple to elevate the performance of these batteries.
To solve these problems, UNIST’s Prof. Yoon Seok Jung’s research team developed a new way to coat the active materials with the solid electrolyte. This solution-process works by diffusing the powder type of active material in the liquid from melted solid electrolyte and vaporizing the solvent. After the solution-process, it became a lot easier to coat the layers of solid electrolyte on the active materials.
The research team also developed a material for the solid electrolyte by adding the iodized lithium (LiI) to the methanol liquid which is the compound (Li4SnS4) based on tin (Sn). The compound’s ionic conductivity was originally low, but increased once mixed with LiI. Consequently, by combining two materials together, it became possible to develop the solid electrolyte with high ion conductivity and air stability.
Prof. Jung says, “A newly developed solid electrolyte has the high ion conductivity and no toxicity problem. In addition, the prices of a raw material and a solvent (methanol) are comparatively low. With this technology, commercialization of solid lithium battery will be available sooner than we thought.”
Image credits: UNIST