Korean research boosts lithium battery stability, efficiency, density

Researchers at the Seoul National University of Science and Technology (SeoulTech) have developed a breakthrough lithium-ion battery technology with the potential to transform energy storage systems by making them more reliable and cost-effective.

SeoulTech Professor Dongwook Han and his research group developed an innovative technique to enhance high-voltage LiNi₀.₅Mn₁.₅O₄ (LNMO) cathodes.

By engineering a lithium-vacant topotactic subsurface – comprising an ordered lattice structure – with a protective K₂CO₃ (potassium-carbon trioxide) surface layer on cathode particles, the academics enhanced the stability, longevity, and performance of lithium-ion batteries.

Though known for its thermal stability and cost-effectiveness as a promising material for high-voltage cathodes, LNMO is limited by undesirable side reactions such as electrolyte decomposition, which decreases cathode performance over time.

The lithium-vacant subsurface pathways engineered by the researchers improve lithium-ion migration and the K₂CO₃-enriched layer protects the cathode from electrolyte decomposition.

Han said the researchers performed the feat using a potassium hydroxide (KOH)-assisted wet chemistry method. He added, “The synergistic effect of these layers results in a remarkable electrochemical charge/discharge cycling performance and increased thermal stability of LNMO cathodes.”

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- and then solid-state reactions.

The prepared R-LNMO cathodes were then subjected to surface modification by treating the particles with an aqueous solution of KOH. That resulted in the formation of surface-modified LNMO: LNMO_KOH.

The LNMO_KOH and R-LNMO cathode particles were then tested for physicochemical and electrochemical characteristics. The researchers described the findings as “remarkable,” as they suggested enhanced thermal stability and better energy storage in the LNMO_KOH particles.

The cathodes exhibited a discharge capacity of around 110 mAh/g with 97% capacity retention after 100 cycles, a notable improvement from the 89 mAh/g discharge capacity and 91% retention of the untreated LNMO cathodes.

The engineered material also showed potential for faster charging with reduced impurity and increased porosity within its structure.

“Our technology is not limited to LNMO but can also be applied to commercial cathode materials, including high-performance Li[Ni₁-y-zCoyMnz]O2 [Lithium nickel manganese cobalt oxide] and LiFePO₄ [lithium ferro-phosphate devices],” said Han. “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.”

The research paper explaining the method was published in Volume 499 of the Chemical Engineering Journal, dated Nov. 1, 2024.

From pv magazine Australia.