Seoul National University of Science and Technology boosts Li-ion battery performance using surface technology
Researchers modify LNMO cathodes for boosting battery lifespan, stability, and energy density of Li-ion batteries
image: Researchers engineer Li-vacant topotactic sub surfaces with potassium carbonate surfaces for improving Li-ion migration and increasing energy storage of Li-ion batteries.
Credit: Dongwook Han from Seoul National University of Science and Technology
With the rising global demand for cost-effective sustainable batteries, lithium-ion batteries are at the forefront as energy storage solutions. However, achieving a high energy density with long-term stability in such batteries is essential to extend the usage time of electric devices. LiNi₀.₅Mn₁.₅O₄ (LNMO), known for its thermal stability and cost-effectiveness, is a promising material for high-voltage cathodes. Yet, its application is limited by undesirable side reactions such as electrolyte decomposition, which decreases its performance over time.
In a pioneering study, Prof. Dongwook Han, a professor from Seoul National University of Science and Technology, and his team of researchers introduced a dual engineering approach to enhance the performance of LNMO cathodes. The team engineered Li-vacant subsurface pathways to improve lithium-ion migration and a K₂CO₃-enriched protective layer to protect the cathode from electrolyte decomposition. Their study was made available online on October 10, 2024, and was published in Volume 499 of the Chemical Engineering journal on November 1, 2024.
"To enhance the performance of LNMO cathodes, we introduced a K2CO3-enriched external surface and a partially delithiated subsurface of LNMO particles through a KOH-assisted wet chemistry method. The synergistic effect of these layers results in a remarkable electrochemical charge/discharge cycling performance and increased thermal stability of LNMO cathodes," says the lead author, Prof. Han.
The surface-engineered cathodes were prepared in a two-step process. First, the regular LNMO (R-LNMO) cathodes were synthesized using co-precipitation-assisted hydrothermal followed by solid-state reactions. The prepared R-LNMO cathodes were then subjected to surface modification by treating the particles with an aqueous solution of KOH. This resulted in the formation of surface-modified LNMO, or simply LNMO_KOH.
The LNMO_KOH and R-LNMO cathode particles were tested for their physicochemical and electrochemical characteristics using advanced techniques. The findings were remarkable, suggesting enhanced thermal stability and better energy storage in the LNMO_KOH particles. The cathodes exhibited a discharge capacity of ~110 mAh/g with 97% capacity retention after 100 cycles, a notable improvement from the 89 mAh/g discharge capacity and the 91% retention of untreated LNMO cathodes. Moreover, the engineered material also showed potential for faster charging with reduced impurities and increased porosity within its structure.
Reflecting on the broader applications of his study, Prof. Han states, “Our technology is not limited to LNMO but can also be applied to commercial cathode materials, including high-performance Li[Ni1-y-zCoyMnz]O2 (NMC) and LiFePO4 (LFP). We believe this will advance the applications of batteries in large-scale electric vehicles and energy storage systems by enabling high energy density and exceptional safety.”
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Reference
DOI: 10.1016/j.cej.2024.156590
About the institute Seoul National University of Science and Technology (SEOULTECH)
Seoul National University of Science and Technology, commonly known as 'SEOULTECH,' is a national university located in Nowon-gu, Seoul, South Korea. Founded in April 1910, around the time of the establishment of the Republic of Korea, SEOULTECH has grown into a large and comprehensive university with a campus size of 504,922 m2.
It comprises 10 undergraduate schools, 35 departments, 6 graduate schools, and has an enrollment of approximately 14,595 students.
Website: https://en.seoultech.ac.kr/
About the author
Prof. Dongwook Han is currently an Associate Professor in the Department of Future Energy Convergence at Seoul National University of Science and Technology in the Republic of Korea. He received his Ph.D. in 2012 from the Korea Advanced Institute of Science and Technology (KAIST), specializing in cathode materials for Li-ion storage. He worked at Samsung Advanced Institute of Technology (SAIT) until 2015, followed by positions at the Korea Automotive Technology Institute (KATECH) until 2017 and Hallym University until 2023. His research interests encompass functional electrode materials for metal-ion rechargeable batteries utilizing organic or aqueous electrolytes.