A team at UNIST in South Korea, led by Professor Hyeon Jeong Lee, has pinpointed the cause of internal cracking in single-crystal lithium nickel manganese oxide (LNMO) cathodes, a critical component in high-performance batteries. Their research, published on April 11, 2025, in Angewandte Chemie International Edition, offers a solution to enhance battery durability.
Single-crystal cathodes, while lacking grain boundaries that cause intergranular cracking, are still susceptible to internal cracks during rapid charging and discharging. The team discovered that uneven lithium-ion diffusion creates localized stress, leading to cracks when the crystal's strength is exceeded.
The researchers introduced magnesium into the crystal lattice to act as a structural support, which inhibits the contraction of ion diffusion pathways and boosts lithium-ion mobility, reducing internal stresses. Experimental results confirmed that magnesium-doped single-crystal cathodes showed significant stability and reduced crack formation under rapid cycling.
"This study provides a clear understanding of the mechanical degradation mechanisms in single-crystal cathodes," said Professor Lee. The integration of experimental and computational approaches has established an effective design strategy to enhance their structural integrity, crucial for the commercialization of next-generation high-performance batteries.