Crystal Growth of Li[Ni1/3Co1/3Mn1/3]O2 as a Cathode Material for High-Performance Lithium Ion Batteries

Recently, there has been a tremendous effort to solve our energy problem by developing multiple alternative routes to energy conversion. Many of these conversion technologies operate cyclically (e.g., photovoltaics generate energy during daytime hours) and require some type of energy storage. Although batteries technologies exist for this purpose, there are multiple issues limiting their performance and lifetime. In addition, current materials (e.g., cathodes such as LiCoO2) suffer from poor energy densities, degradation and are associated with high costs.

Li[Ni1/3Co1/3Mn1/3]O2 was recently discovered to be a novel cathode material for lithium ion batteries. This material was introduced by Makimura and Ohzuku (2001) and has since received a lot of attention due to its high reversible capacity, environmentally friendly nature, long life cycle and light weight. In addition, the substitution of Mn and Ni cations render it a less costly than LiCoO2. Since its initial discovery, some research has been done to investigate the performance of this promising material.

One limiting factor of this and other cathode materials is the lack of control of crystal size and shape. Inhomogeneous particle sizes lead to reduced performance and lifetime. A thorough investigation of the crystal growth behavior of these materials would provide critical insight to controlling the material size and shape and lead to longer lasting, higher performance cathodes.

In this study, we have investigated the crystal growth behavior and cation arrangement of the Li[Ni1/3Co1/3Mn1/3]O2 material. Samples were heated between 700-900 0C at for set durations. Scanning Electron Microscopy and X-Ray Diffraction analysis enabled the determination of activation energy and thus, the mode of diffusion during calcinations. We believe that by understanding the mechanism of diffusion during calcinations, we can completely control the size and morphology to provide an optimal cathode material.