KIST Increases Energy Densities of Lithium Batteries by 25%

For amplifying energy densities of high-capacity lithium batteries, a team of researchers from the Korea Institute of Science and Technology (KIST) has developed a processing technology. The joint research team is comprised of Dr. Minah Lee, Center for Energy Storage Research, and Dr. Jihyun Hong, Center for Energy Materials Research, both of the Clean Energy Institute in KIST.

The pursuit of next-generation battery architectures has allowed scientists to explore various alternative materials, and silicon has been regarded as a good candidate material for some time. Using this rich element as the anode of a lithium-ion battery can significantly increase the energy densities.

Presently, lithium batteries use graphite as the material of the anode. This positively charged electrode cooperates with a negatively charged cathode to shuttle lithium ions back and forth during the charging process. But replacing graphite with silicon can store four times as many lithium ions as the phone can last for a few days, or the car can travel hundreds of miles per charge.

But it turns out that when charged in the initial cycle, a battery with a silicon-based anode loses more than 20% of the lithium ions it uses for electricity storage, which results in an issue of reduced battery capacity. To resolve this issue, KIST researchers have developed a method of adding extra lithium before battery assembly to compensate the lithium loss during high-capacity lithium battery cycling. Previous methods of this lithium 'pre-loading' use lithium powder, the use of which has safety and price concerns.

Scientists from the KIST have proposed a new method of pre-installing lithium on the anode of a silicon battery to increase its energy density, the team used a silicon anode instead of the lithium anode. Immersing in a special solution for 5 minutes to initiate a chemical reaction and allow lithium ions to penetrate the electrode.

The prelithiated silicon-based anode developed by the research team loses less than 1% of active lithium in the first charge, yielding a high initial battery efficiency of 99% or higher. A battery manufactured with the prelithated anode exhibited an energy density 25% higher than that of a comparable battery using a graphite anode available on the market.

"By incorporating a computational materials science technique into the design of an optimal molecular structure, we were able to improve the efficiency of a high-capacity of the lithium batteries, silicon-based anode by leaps and bounds with the simple method of just controlling the solution temperature and reaction time," said Dr. Minah Lee of the KIST, who headed the research. "As this technology is readily applicable to the roll-to-roll process used in existing battery manufacturing facilities, our method has the potential to achieve a breakthrough in the implementation of silicon-based anodes for practical batteries, and enable current lithium batteries owns high energy densities." The study was published in Angewandte Chemie: International Edition.

• < Prev
• Next >