A new method improves lithium-ion battery cathodes, increasing durability, reducing energy loss, and addressing instability, offering a solution for EVs and energy storage.
A research team from Pohang University of Science and Technology has developed a method to improve the durability of lithium-rich layered oxide (LLO) material, a promising next-generation cathode for lithium-ion batteries (LIBs).
Lithium-ion batteries are crucial for applications like electric vehicles and energy storage systems (ESS). LLO material provides up to 20% more energy density than traditional nickel-based cathodes by reducing nickel and cobalt content while increasing lithium and manganese. As a more affordable and sustainable option, LLO has gained significant attention. However, issues like capacity fading and voltage decay during charge-discharge cycles have limited its commercial use.
Previous studies have linked structural changes in the cathode during cycling to these problems, but the exact cause of the instability has remained unclear. Existing strategies to improve LLO’s structural stability have not addressed the root issue, which has hindered its widespread use.
The team focused on the role of oxygen release in destabilizing the LLO structure during cycling. They suggested that improving the chemical stability of the cathode-electrolyte interface could prevent oxygen release. By enhancing the electrolyte composition, they strengthened this interface, significantly reducing oxygen emissions.
The research team’s improved electrolyte achieved an impressive energy retention rate of 84.3% after 700 charge-discharge cycles, a significant improvement compared to conventional electrolytes, which retained only 37.1% of energy after 300 cycles.
The study also found that structural changes on the LLO material’s surface greatly affected its stability. By addressing these changes, the team significantly enhanced the cathode’s lifespan and performance while reducing undesirable reactions, such as electrolyte decomposition within the battery.
The research team used synchrotron radiation to analyze the chemical and structural differences between the surface and interior of the cathode particles. This analysis revealed that the stability of the cathode surface is crucial for the material’s overall structural integrity and performance. The team believes this research will offer new directions for developing next-generation cathode materials.
Reference: Gukhyun Lim et al, Decoupling capacity fade and voltage decay of Li-rich Mn-rich cathodes by tailoring surface reconstruction pathways, Energy & Environmental Science (2024). DOI: 10.1039/D4EE02329C
