SEARCH

SEARCH BY CITATION

Keywords:

  • spinel;
  • layered materials;
  • cathodes;
  • core-shell materials;
  • Li-ion batteries

Abstract

In an attempt to overcome the problems associated with LiNiO2, the solid solution series of lithium nickel-metal oxides, Li[Ni1–xMx]O2 (with M = Co, Mn, Al, Ti, Mg, etc.), have been investigated as favorable cathode materials for high-energy and high-power lithium-ion batteries. However, along with the improvement in the electrochemical properties in Ni-based cathode materials, the thermal stability has been a great concern, and thus violent reaction of the cathode with the electrolyte needs to be avoided. Here, we report a heterostructured Li[Ni0.54Co0.12Mn0.34]O2 cathode material which possesses both high energy and safety. The core of the particle is Li[Ni0.54Co0.12Mn0.34]O2 with a layered phase (R3-m) and the shell, with a thickness of < 0.5 μm, is a highly stable Li1+x[CoNixMn2–x]2O4 spinel phase (Fd-3m). The material demonstrates reversible capacity of 200 mAhg-1 and retains 95% capacity retention under the most severe test condition of 60 °C. In addition, the amount of oxygen evolution from the lattice in the cathode with two heterostructures is reduced by 70%, compared to the reference sample. All these results suggest that the bulk Li[Ni0.54Co0.12Mn0.34]O2 consisting of two heterostructures satisfy the requirements for hybrid electric vehicles, power tools, and mobile electronics.