▲All-solid-state electricity and expected effects realized using the developed elastomer-based solid electrolyte (Image source: KAIST)



Solving electric vehicle driving range and safety issues
Presenting new possibilities in secondary battery development

A research team from KAIST and Georgia Institute of Technology has developed the world's highest-performance solid-state battery that can travel between Seoul and Busan on a single charge, making 'dream battery' technology a reality.

The research team of Professor Beomjun Kim of the Department of Chemical and Biomolecular Engineering at KAIST announced on the 13th that they developed a new concept of elastomeric polymer electrolyte through joint research with Professor Seungwoo Lee's team at Georgia Institute of Technology in the United States and implemented the world's highest-performance all-solid-state battery through this.

All-solid-state Li-metal batteries are a future technology that can prevent fires and automobile accidents by replacing the highly volatile liquid electrolytes used in secondary batteries with solid electrolytes.

This is a 'dream battery technology' that can dramatically improve energy density compared to currently commercialized lithium-ion batteries, thereby securing automobile driving range and solving safety issues.

The joint research team developed an elastomer (rubber) type polymer electrolyte that has excellent lithium (Li) ion conductivity at room temperature and mechanical elasticity.

Applying this to an all-solid-state battery, it shows the world's highest performance of 410Wh/kg. An all-solid-state lithium metal battery was implemented.

The introduction of this technology is expected to make it possible to build electric vehicles that can travel up to 800 km on a single charge (up from the current range of 500 km), and is also expected to dramatically improve the stability of lithium-ion batteries using existing liquid electrolytes.

The research team developed an elastomeric polymer solid electrolyte that three-dimensionally connects plastic crystal materials with extremely high lithium ion conductivity inside an elastomer with excellent elasticity like rubber.

The electrolyte developed by the research team has an ionic conductivity of 10-3 S/cm, which is approximately 100 times higher than that of the existing representative polyethylene oxide (PEO)-based polymer electrolyte.

In addition, the electrolyte, which has excellent elasticity like rubber, suppresses the growth of lithium dendrites, which is the biggest problem in stability during battery charging and discharging, thereby securing excellent battery performance and stability.

The developed polymer electrolyte demonstrated stable operation at high voltages of over 4.5 V in an all-solid-state battery composed of a thin lithium metal negative electrode and a nickel-rich positive electrode (NCM-Ni83), and exhibited the world's highest energy density of over 410 Wh/kg.

Professor Kang Ki-seok of Seoul National University, an authority in the field of secondary batteries, said, “The global development competition for all-solid-state secondary batteries is fierce,” and “The research team’s latest development will present new possibilities for the development of secondary batteries.”

Professor Kim Beom-jun said, "It is very significant that we have secured the material source technology by developing a completely new type of solid electrolyte called an elastomeric electrolyte, which is completely different from existing ones."

Meanwhile, this study, in which KAIST's Han Jeong-hoon and Georgia Institute of Technology's Lee Seung-hoon participated as joint first authors, was published in the international academic journal Nature on January 13.

This study was supported by the Korea Research Foundation's Mid-Level LeapThis work was carried out with the support of the Research Project, Future Materials Discovery Project, and Basic Research Laboratory Support Project, and Dr. Byeong-Gak Kim of the Korea Research Institute of Chemical Technology and Dr. Gyu-Nam Jeong of the Korea Institute of Energy Research participated in the joint research.