The Role of Zr Doping in Stabilizing Li[Ni_0.6Co_0.2Mn_0.2]O₂ as a Cathode Material for Lithium‐Ion Batteries

Abstract

Ni‐rich layered LiNi1−x−yCoxMnyO2 systems are the most promising cathode materials for high energy density Li‐ion batteries (LIBs). However, Ni‐rich cathode materials inevitably suffer from rapid capacity fading and poor rate capability owing to structural instability and unstable surface side reactions. Zr doping has proven to be an effective method to enhance the cycle and rate performances by stabilizing the structure and increasing the Li+ diffusion rate. Herein, effects of Zr‐doping on the structural stability and Li+ diffusion kinetics are thoroughly investigated in LiNi0.6Co0.2Mn0.2O2 (LNCM) cathode material using atomic‐resolution scanning transmission electron microscopy imaging, XRD Rietveld refinement, and density functional theory calculations. Zr doping mitigates the degree of cation mixing, decreases the structural transformation, and facilitates Li+ diffusion resulting in improved cyclic performance and rate capability. Based on the obtained results, an atomistic model is proposed to explain the effects of Zr doping on the structural stability and Li+ diffusion kinetics in LNCM cathode materials.

Enabling high energy lithium metal batteries via single-crystal Ni-rich cathode material co-doping strategy

“…7d). The accumulation of internal-strain in undoped SNCM during cycling at the high charging cut-off voltage of 4.6 V is mainly ascribed to responsible for the generation of nanocracks [52][53][54] , and it will impede the Li + diffusion in the sample and cause the structure collapse.…”

A review on nickel-rich nickel–cobalt–manganese ternary cathode materials LiNi0.6Co0.2Mn0.2O2 for lithium-ion batteries: performance enhancement by modification

“…Related studies have shown that the thermal stability of active materials doped with Zr atoms in the lattice is significantly enhanced. 53 Another work 109 explains the mechanism of Zr 4+ doping used to suppress the phase transition. The atomic resolution TEM images presented in Fig.…”

A review of the degradation mechanisms of NCM cathodes and corresponding mitigation strategies

“…Zhang et al [251] showed that co-doping the TM and O sites with Al 3+ and (PO4) 3respectively reduced cation mixing and improved the overall stability of the cathode and cycling ability, although with a slightly deleterious effect to the initial capacity. Finally, simultaneous Li and O site doping has also been shown to enlarge the interlayer spacing, thus improving Li diffusion and rate capability [235,236].…”

“…It can prevent extensive lattice parameter change during battery operation, mitigate oxygen evolution and cation migration, thus slowing down surface reconstruction and rapid electrolyte deterioration. Additionally, simultaneous Li and O site doping has been shown to enlarge the interlayer spacing, thus improving Li diffusion and rate capability[235,236].…”