Structural, electrochemical and Li-ion transport properties of Zr-modified LiNi0.8Co0.1Mn0.1O2 positive electrode materials for Li-ion batteries

• Published in: Journal of power sources Vol. 410-411; no. C; pp. 45 - 52
• Main Authors: Gao, Shuang, Zhan, Xiaowen, Cheng, Yang-Tse
• Format: Journal Article
• Language: English
• Published: United States Elsevier B.V 15.01.2019; Elsevier
• Subjects: Direct current polarization; Li-ion battery; Li-ion diffusion; Ni-rich cathode; Zirconates coating; Zirconium doping; Zirconates coating; Li-ion diffusion; Ni-rich cathode; Direct current polarization; Li-ion battery; Zirconium doping
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2018.10.094

We modify a nickel-rich layered LiNi0.8Co0.1Mn0.1O2 (NCM811) positive electrode material by substituting the transition metals with Zr to mitigate its structural instability and capacity degradation. We show that Zr, over a concentration range of 0.5–5.0 at.%, can simultaneously reside on and expand the lattice of NCM811 and form Li-rich lithium zirconates on their surfaces. In particular, Li(Ni0.8Co0.1Mn0.1)0.99Zr0.01O2 (1% Zr-NCM811) exhibits the best rate capability among all the compositions in this study. It shows higher cycling durability than the raw NCM811 at both low and high current density lithiation and de-lithiation. According to X-ray photoelectron spectroscopy and cyclic voltammetry measurements, the 1% Zr-NCM811 sample is more chemically/electrochemically stable than the raw. In addition to comparing the diffusivities in the coin-cell measurements, we demonstrate that Zr modification can facilitate Li-ion diffusion in the NCM811 balk material by direct-current polarization measurements. The superior performance of Zr-NCM811 results from the lattice expansion induced by Zr doping and the presence of ion-conducting lithium zirconates partially coated on the surface of Zr-NCM811 particles. •1% Zr-NCM811 witnesses largely improved cycling stability and rate capability.•Zr modification realizes bulk Zr doping and surface zirconate coating simultaneously.•Zr modification increases the Li-ion diffusivity of bulk NCM811.