Professor Park Chulmin's Team at Kumoh National Institute of Technology Achieves World-Class Performance with Innovative Silicon All-Solid-State Battery Development

Overcoming All Limitations of Conventional Silicon Anodes
Achieving Ultra-High Capacity, Ultra-Fast Charging, Low Operating Pressure, and Wide Temperature Stability
Published in "Joule," the Leading Journal in the Field of Energy
Demonstrating World-Class Research Capabilities in All-Solid-State Batteries with Two Consecutive Publications in Joule

On December 8, Kumoh National Institute of Technology announced that the research team led by Professor Park Chulmin from the Department of Materials Engineering (Major in Advanced Materials Engineering) has successfully developed a world-class lithium (Li)-silicon (Si) compound anode material for all-solid-state batteries, in collaboration with research teams from Inha University, the Korea Electrotechnology Research Institute (KERI), and Suncheon National University.

This research achievement was published last month in "Joule" (IF 35.4), a leading international journal in the field of energy. Professor Park Chulmin's research team has now published in Joule, the top journal in the energy field, for two consecutive years, thereby demonstrating their world-class research capabilities in the field of all-solid-state batteries.

From the left) Professor Chulmin Park (Department of Materials Engineering, Kumoh National Institute of Technology), Researcher Dohyun Kim (PhD candidate, Department of Advanced Materials Engineering, Kumoh National Institute of Technology), Professor Gijun Jeon (Inha University), Dr. Junghui Choi (Korea Electrotechnology Research Institute) Provided by Kumoh National Institute of Technology

All-solid-state batteries, in which all components are solid, are next-generation batteries attracting attention as a technology to replace conventional liquid electrolyte-based lithium-ion batteries, which are prone to fire and explosion risks.

However, silicon (Si) anodes have been considered virtually unsuitable for all-solid-state batteries due to several issues: severe volume expansion during charging and discharging, low ionic and electronic conductivity, side reactions with solid electrolytes, and the requirement for a high operating pressure of over 50 MPa.

The research team addressed all these challenges simultaneously through a completely new anode structure design based on Li (lithium)-Si (silicon) compounds.

Professor Park Chulmin's research team systematically analyzed the structures and conductivity characteristics of various lithium-silicon compounds using advanced density functional theory (DFT) calculations.

As a result, they identified that a specific phase of Li-Si compound, rather than conventional silicon or simple composites, is optimal for all-solid-state battery anodes.

In particular, the Li7Si3 phase was experimentally proven to be the most ideal structure for next-generation all-solid-state battery anode materials, as it possesses extremely high ionic and electronic conductivity, a stable reaction mechanism with almost no volume change during charging and discharging, and excellent compatibility with sulfide-based solid electrolytes.

While conventional silicon anodes require high operating pressure to maintain particle-to-particle contact, the Li7Si3 phase, with its high plastic and elastic deformation energies, ensures dense particle contact stability even at low operating pressure.

As a result, the team succeeded in achieving stable electrode performance even at 10 MPa, which is about one-fifth of the 50 MPa required for conventional silicon anodes. This significantly reduces manufacturing process costs and equipment burden, providing a crucial advantage for the commercialization of all-solid-state batteries.

The research team fabricated an all-solid-state battery full cell composed of a Li7Si3 anode, an NCM622 cathode, and a sulfide-based solid electrolyte (Li6PS5Cl) to verify its performance.

The results demonstrated outstanding performance, including achieving an areal capacity of 15.96 mAh/cm2 (world-class level), maintaining stable cycling for over 2,000 cycles under 6-minute fast-charging conditions, stable operation across a wide temperature range from -10℃ to 80℃, and successful production of a pouch cell, thus confirming its commercial viability and proving the "world-class" characteristics of the all-solid-state battery.

This study is attracting significant attention from both academia and industry, as it fundamentally resolves the long-standing issues of silicon anodes-volume expansion, low conductivity, high-pressure operation, and structural weakness-through innovation in a single material.

Professor Park Chulmin emphasized, "We have proposed a new solution that effectively overcomes the structural and electrochemical limitations of conventional silicon anodes through lithium-silicon compounds," and added, "This technology, with its advantages of high energy density, ultra-fast charging performance, and low operating pressure, will become a key material to accelerate the commercialization of all-solid-state batteries."

He also stated, "We will continue to expand our research into various electrode materials to secure the fundamental technologies that will lead the next-generation battery market."

This research was supported by the Mid-Career Researcher Support Program and the Key Research Institute Program of the National Research Foundation of Korea. The corresponding author is Professor Park Chulmin (Kumoh National Institute of Technology), with Professor Jeon Gijun (Inha University) and Dr. Choi Junghui (KERI) serving as co-corresponding authors.

The first author is Dohyun Kim, a PhD candidate at Kumoh National Institute of Technology, and the co-authors include Professor Kim Byungchul (Suncheon National University), Professor Choi Incheol (Kumoh National Institute of Technology), PhD candidates Yoon Jeongmyung and Lee Younghan, and Dr. P. Thondaiman, a postdoctoral researcher at Kumoh National Institute of Technology.

The research results were published in the online edition of "Joule," one of the world's top international journals in the field of energy.

Joule, published by Cell Press, is recognized as a leading journal in the field of energy, alongside Nature and Science, and is considered one of the world's top three journals.

This content was produced with the assistance of AI translation services.