The attractive cathode material, LiNi0.5Mn1.5O4 for lithium ion batteries was synthesized and its surface was modified by adding LiCoO2 by a sol-gel method. This research is aimed to figure out the effects of LiCoO2 added to pristine LiNi0.5Mn1.5O4. The electrochemical performance was characterized by galvanostatic cycle tests between 3.0 and 4.9V versus Li/Li+ at 0.5 C-rate using the prepared coin cells consisting of a series of LiNi0.5Mn1.5O4 cathode each, lithium metal anode, and 1M LiPF6 in DMC/EC (1:1 v/v) electrolyte. In XRD results, there exist some impurity phases attributed to the added LiCoO2 even at the high sintering temperature, but these impurities did not exert influence on the electrochemical behavior of the samples. Also, the charge/discharge results are in good agreement with the XRD data. As increasing the amount of LiCoO2, (220) phase XRD peak which means a degree of cation mixing developed and this affected the amount of inserted/extracted Li ions. Thus, cobalt-rich samples showed the lower capacity than pristine LiNi0.5Mn1.5O4. However, a little amount of LiCoO2-added LiNi0.5Mn1.5O4 showed the best electrochemical properties. The improved kinetics and electrochemical properties are discussed in detail.
ASJC Scopus subject areas
- Chemical Engineering(all)