All-solid lithium batteries in the offing

Seoul: A team of Korean scientists has discovered a new way to develop all-solid-state lithium batteries without a risk of conflagration or explosion.

The joint research team of professor Yoon Seok Jung of the Ulsan National Institute of Science and Technology's School of Energy and Chemical Engineering and professor Seng of Seoul National University developed the new method that involves melting the solid electrolyte and coating that melted electrolyte around the electrodes.

The organic liquid electrolyte, mainly used in existing lithium-ion batteries, has a characteristic of easily getting gasified or burned. Therefore, all-solid-sate lithium batteries are now getting an attention as the alternative option since they are non-flammable.

However, 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 revelation of batteries.

To solve these problems, professor Jung's research team developed a way to coat the active materials with the solid electrolyte.

This process called the solution-process works by diffusing the powder type of active material in the liquid from melted solid electrolyte and vaporising the solvent.

After the solution-process, it became more possible 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 iodised lithium (LiI) to the methanol liquid which is the compound (Li4SnS4) based on tin (Sn).

The compound's ionic conductivity was originally low, but it got increased by getting mixed with LiI.

Consequently, by combining two materials together, it became possible to develop the solid electrolyte with high ion conductivity and air stability.

The research outcome was introduced on the online journal Advanced Materials on December 22 last year.