Comparative study of polycrystalline and single-crystal NCM811 cathode materials: the role of crystal defects in electrochemical performance

Abstract

The lower crystal structure defects caused by asymmetric Li/Ni mixing in the single crystal morphology of NCM811 material determine its better structural stability than the polycrystalline morphology.

Optimizing NCM811 nickel-rich cathode stability via suppressing asymmetric Li/Ni mixing by a “non-intrusive” strategy

“…Due to the reduction of lattice defects of Li/Ni asymmetric mixing, the modified cathode has the lattice characteristics of some single crystal particles under the polycrystalline morphology of a micron scale. 21 This structural optimization significantly improved the cycle stability of the modified material. At a 1C charge–discharge rate, the modified cathode demonstrated a capacity retention rate of 60.27% (111.47 mA h g −1 ) after 300 cycles, nearly 20% higher than that of the original NCM811 cathode (72.96 mA h g −1 , 40.13%).…”

Influence of cathode materials on thermal characteristics of lithium-ion batteries

“… Qiu et al (2019) employed a protocol for incorporating Zr and F into NCM materials using conventional solid-state sintering techniques. This doping method alleviated the electrochemical polarization and significantly enhanced the structural stability, and the composite achieved a high capacity retention rate of 90.5% after 200 cycles at 1 C. Zhu et al (2023) investigated the electrochemical properties of polycrystalline and monocrystal NCM811 materials, and the results showed that polycrystalline samples had higher discharge capacity and better rate performance than monocrystal samples, while monocrystal materials had better capacity retention and cycle stability. In addition, owing to the similar proportion of nickel as NCM811, LiNi 0.8 Co 0.15 Al 0.05 O 2 (NCA) is seen as an alternative to provide high energy and power output for electric vehicles.…”