LG Energy supported UC San Diego researchers in a promising discovery that involved two types of popular battery technology. The solid-state battery was created using an all-silicon anode. This could provide long life, high energy density, and fast charging. This could make EVs more affordable and more practical.
Silicon anodes are highly sought-after because it has a higher energy density than current graphite anodes. Problem is that silicon anodes can expand and shrink rapidly as batteries charge and discharge, especially with liquid electrolytes used in lithium-ion cell batteries. This has kept them out of commercial batteries.
Solid-state batteries, which have liquid instead of solid electrolytes, face a challenge because they use metallic lithium anodes. These anodes must be maintained at 140 degrees F during charging. This makes them less useful in cold weather and requires heaters that use valuable energy.
According to the US San Diego team, there is a solution for both of these problems: a special silicon anode that can be used in a solid state battery. They removed the carbon and binding agents that are commonly used in silicon anodes, and replaced the liquid electrolyte by a sulfide based solid electrolyte.
These changes led to the discovery that all-silicon anodes are more stable in solid electrolyte. They retain 80 percent of their capacity after 500 charges and discharge cycles at room temperature. The team also noted that it allowed for faster charging than other silicon anode batteries.
Unigrid Battery has licensed the technology to the team, and LG Energy Storage plans on expanding the research. According to Darren H.S. Tan, the lead author of the work, it is especially promising for grid storage. Tan. The team admitted that it is still in its experimental stage and that there is "more work to be done". Many batteries that perform well in labs don't work in the real world. The paper was published in Science journal. It also appeared earlier on Arxiv.