The research results on all-solid-state battery cathode materials conducted by the Korea Electrotechnology Research Institute (KERI) in collaboration with professors from Kumoh National Institute of Technology and Inha University were selected as the cover paper of a world-class journal in the energy field.


The Korea Electrotechnology Research Institute announced on the 21st that a research paper proposing a 'tin-iron compound (FeSn2)' as a cathode material was published as the cover paper for the October issue of the world-renowned journal 'Joule'.

Joule is the sister journal of Cell, one of the top three science journals along with Nature and Science, and is a world-class journal with an impact factor (IF) of 38.6.

The corresponding authors of the paper are KERI Next Generation Battery Research Center Director Ha Yoon-cheol, Kumoh National Institute of Technology Department of Materials Science and Engineering Professor Park Cheol-min, and Inha University Department of Environmental Engineering Professor Jeon Ki-jun. The first author is Kumoh National Institute of Technology Doctoral Program Researcher Lee Young-han. Co-authors included KERI Battery and Materials Process Research Center Director Choi Jeong-hee, Kumoh National Institute of Technology Department of Advanced Materials Engineering Professor Choi In-cheol, and researchers Kim Do-hyeon (doctoral course) and Yoon Jeong-myeong.

All-solid-state batteries replace the 'electrolyte' that transfers ions between the positive and negative electrodes with a solid that has an extremely low risk of fire or explosion, rather than the existing flammable liquid.

On the other hand, solid-state batteries require much more technological prowess, such as securing stability during the charging and discharging process, due to the keyword “solid.” In particular, the cathode has a significant impact on the charging speed and lifespan of the battery, so the material it is made of is very important.

Currently, lithium metal (Li-metal) is being studied the most as an anode material for all-solid-state batteries.

On the other hand, lithium metal grows in the shape of tree branches on the surface of the lithium as it is repeatedly charged and discharged, causing so-called 'dendrite growth', which threatens the life and stability of the battery by causing internal short circuits. In addition to lithium metal, there are silicon anode materials, but they have many problems such as low electron and ionic conductivity and cracks due to volume expansion.

The anode material presented by KERI and the university team this time is a tin (Sn)-based alloy material called 'tin-iron compound (FeSn2)'. Through a thorough analysis of mechanical properties, the research team discovered that FeSn2 has the characteristic of having particles that become smaller through a recombination reaction even during repeated charging and discharging. Through this, they confirmed that it maintains close contact between internal solid particles in an all-solid-state battery for a long period of time and forms a dense and uniform electrode. Even in an environment where external stimuli are applied, FeSn2 has high elasticity and deformation energy, and thus has good electrochemical stability without cracks.

To verify the technology, the research team created a test 'all-solid-state battery full cell' using an FeSn2 cathode, an NCM622 (nickel 6, cobalt 2, manganese 2) anode, and a sulfide solid electrolyte (Li6PS5C1), and as a result, it achieved a 'capacity per area (15.54 mAh/cm2)' that is five times higher than that of existing lithium-ion batteries.

In addition, rapid charge/discharge was performed over 1,000 cycles under 3-minute (20C current density) and 6-minute (10C current density) time conditions, and a high 'capacity retention rate' of over 70-80% was recorded.

In addition, the research team evaluated the performance of the all-solid-state battery FeSn2 cathode in a 'pouch cell' form close to a prototype, and demonstrated commercial feasibility by recording a high energy density of over 255 Wh/kg.

KERI Next-Generation Battery Research Center Director Ha Yoon-cheol said, “Our achievement is significant in that it demonstrates the great potential of tin-based alloy cathode materials, breaking away from the existing practice of researching all-solid-state battery cathode materials, which has focused on lithium metal and silicon.”

Professor Park Cheol-min of Kumoh National Institute of Technology expressed his ambition, saying, “We will contribute to the commercialization of non-flammable all-solid-state batteries by developing stable, high-performance cathode materials that overcome limitations.”

Meanwhile, KERI is a government-funded research institute under the National Research Council of Science and Technology of the Ministry of Science and ICT.