The effects of extra Li content, synthesis method, sintering temperature on synthesis and electrochemistry of layered LiNi1/3Mn1/3Co1/3O2

The effects of extra Li content, different synthesis method and sintering temperature on synthesis, structure and electrochemistry of LiCo1/3Ni1/3Mn1/3O2 were investigated. It was shown that extra Li content, homogeneous precursor and a high sintering temperature contributed to the formation of single phase compound. Extra Li content not only accelerated formation of pure phase due to effectively suppressing development of NiO impurity, but also brought about considerable variations in electrochemistry. In the case of x = 1.3 (the molar ratio of Li versus M (M = Co1/3Ni1/3Mn1/3) at starting materials), a plateau-like stage at >4.3 V during the initial charge process was apparently observed, accompanying a remarkably improved initial charge capacity. Different precursors derived from different synthesis methods caused the impressive differences in electrochemistry of LiCo1/3Ni1/3Mn1/3O2. Homogeneous precursors derived from spray-drying method resulted in significantly improved electrochemical performances in contrast with ones obtained by direct decomposition of acetates and even subsequent ball-milling. This may be related to the reduced occupancy of transitional metal ions in Li layers, smaller particles size and possibly good material homogeneity in LiCo1/3Ni1/3Mn1/3O2.