Ongoing research efforts are dedicated to identifying suitable anode materials for all-solid-state Li-ion batteries (ASSLIBs) to address dendrite growth issues in Li-metal anodes. While various alternatives have been proposed, they also have their limitations. Solid-state batteries (SSBs) have replaced combustible liquid electrolytes with solid electrolytes, significantly reducing the risk of fire or explosion.
However, SSBs require advanced technology to ensure electro-chemo-mechanical stability during charging and discharging processes due to their solid nature. The choice of anode material is crucial as it significantly impacts the charging rate and lifespan of the battery.
Currently, Li-metal is the most extensively researched anode material for SSBs. However, dendrite growth occurs with repeated charging and discharging, leading to internal short circuits and threatening the battery’s lifespan and stability. Silicon anode materials are also available, but they face challenges such as low electronic and ionic conductivity and cracks caused by volumetric expansion.
The anode materials developed by KERI, in collaboration with Kumoh National Institute of Technology and Inha University, are tin(Sn)-based alloy materials, particularly ‘FeSn2.’ The research team found that FeSn2 demonstrates particle size reduction during repeated charging and discharging, maintaining contact between solid particles in SSBs for extended periods, resulting in a dense and uniform electrode.
FeSn2 also exhibits high elasticity and deformation energy, ensuring excellent electrochemical stability without cracking, even in challenging environments. The team tested the technology using an ‘SSB full cell’ with FeSn2 anode, NCM622 cathode, and sulfide solid electrolytes (Li6PS5C1), achieving an areal capacity of 15.54 mAh/cm², five times higher than conventional lithium-ion batteries.
Moreover, the battery showed a capacity retention of over 70-80% after over 1,000 cycles of high-rate charging and discharging under 3-minute (20C current density) and 6-minute (10C current density) conditions.
The research team successfully assessed the performance of the FeSn2 anode in SSBs by incorporating it into a prototype’ pouch cell’ format. This resulted in a remarkably high energy density of over 255 Wh/kg, showcasing its potential for commercial use. These findings have been featured as a cover article in the esteemed October issue of Joule, a top-tier international journal in the energy field with an impressive impact factor (IF) of 38.6.
Yoon-Cheol Ha, Director of the Next Generation Battery Research Center at KERI, stated, “Our achievement is significant as it breaks away from the conventional focus on Li-metal and silicon in the research of anode materials for SSBs, demonstrating the great potential of tin-based alloy anode materials.”
Additionally, Professor Cheol-Min Park of Kumoh National Institute of Technology expressed his ambition, stating, “Through the development of stable, high-performance anode materials that surpass existing limitations, we aim to contribute to the commercialization of non-flammable SSBs.”
Journal reference:
- Young-Han Lee, Do-Hyeon Kim, Jeong-Myeong Yoon, In-Chul Choi, Jeong-Hee Choi, Ki-Joon Jeon, Yoon-Cheol Ha, Cheol-Min Park. Empowering all-solid-state Li-ion batteries with self-stabilizing Sn-based anodes. Joule, 2024; DOI: 10.1016/j.joule.2024.08.011
