PNNL

Abstract

Zr surface modification was performed on Li- and Mn-rich (LMR) cathode material (Li1.2Ni0.13Co0.13Mn0.54O2) to suppress the detrimental phase transformation upon cycling and enhance its electrochemical performance. Using a wet chemical method, a Zr-based rock-salt layer with a thickness of 1~2 nm was formed on the surface of the LMR. Controlled studies reveal that the Zr-based layers can effectively suppress the phase transformation, leading to an enhanced long-term cycling performance and rate capability. At C/3, the Zr-modified LMR material was found to deliver an initial discharge specific capacity of 211 mAh g-1, and maintain a capacity of 182 mAh g-1 after 100 cycles. Even at high rates of 1, 2 and 3C, it still displays high discharge capacities of 178, 156 and 143 mAh g-1, respectively. This work reports for the first time the detailed mechanisms at atomic scale of how Zr modification can be effectively used to tailor the surface microstructures of high energy cathode materials to improve their long-term stability and cycle life.