The Korea Institute of Science and Technology (KIST) announced on December 4 that its research team led by Dr. Oh Shi-hyeong at its Center for Energy Convergence Research and Seoul National University professor Choi Jang-wook developed a new positive electrode material overcoming surface degradation by forming a nanometer-size high-ion conductivity surface layer on a lithium- and manganese-rich (LMR) transition metal oxide used as the positive electrode material of a high-capacity battery.
These days, LMR materials are drawing much attention as a next-generation positive electrode material. These materials are characterized by having an energy density higher than those of existing commercial positive electrode materials along with a higher level of safety. However, commercialization of the materials has been rather limited due to the instability of their crystal structures during charging and discharging.
The research team formed a novel surface structure so that the surface of the LMR positive electrode material can be stabilized and lithium ion transfer can be accelerated. The team coated the surface of the LMR positive electrode material through a simple single process with a high-ion conductivity zirconium-based mixed oxide that has a thickness of one to two nanometers, successfully carrying out lithium ion diffusion on the surface and suppressing material degradation.
The positive electrode material that has the nanometer-size zirconium-containing mixed transition metal oxide layer maintained its excellent initial performance even after 300 times of rapid charging and discharging within two minutes. This means the material is capable of realizing a high capacity and a high output at the same time and capable of reducing electric vehicle (EV) charging time, increasing the driving ranges of EVs, and simplifying EV manufacturing processes when applied to EV batteries.
Details of the research are available in the online edition of the Nano Letters posted on November 16.