Study of the surface modification of LiNi1/3Mn1/3O2 cathode material for lithium ion battery

摘要

The surface of LiNi1/3Co1/3Mn1/3O2 (LNMCO) particles has been studied for material synthesized at 900 C by a two-step process from a mixture of LiOHH2O and metal oxalate [(Ni1/3Co1/3Mn1/3)C2O4] obtained by co-precipitation. Samples have been characterized by X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), Raman scattering (RS) spectroscopy, and magnetic measurements. We have investigated the effect of the heat treatment of particles at 600 C with organic substances such as sucrose and starch. HRTEM images and RS spectra indicate that the surface of particles has been modified. The annealing does not lead to any carbon coating but it leads to the crystallization of the thin disordered layer on the surface of LiNi1/3Co1/3Mn1/3O2. The beneficial effect has been tested on the electrochemical properties of the LiNi1/3Co1/3Mn1/3O2 cathode materials. The capacity at 10C-rate is enhanced by 20% for post-treated LNMCO particles at 600 C for half-an-hour.