The team melted
methanol in Li4SnS4. Melting and coating around the
active materials
for making high-performance all-solid-state batteries.
January 1, 2016) A
new type of solid electrolyte was introduced on Advanced Materials.
Prof. Yoon Seok Jung's team discovered the solution-process
to develop all-solid-state-lithium batteries.
The joint research team of Prof. Yoon Seok Jung (UNIST,
School of Energy and Chemical Engineering) and Prof. Seng M. Oh (Seoul National
University) discovered a new way to develop all-solid-state lithium batteries
without a risk of conflagration or explosion. It is the method of melting the
solid electrolyte and coating that melted electrolyte around the electrodes.
This research outcome was introduced on Advanced Materials on December 22,
2015.
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, Prof. 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 vaporizing 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 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 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.