High performance LiFePO4/C cathode for lithium ion battery prepared under vacuum conditions

LiFePO4/C with smaller particle size (0.3-0.6 mu m) was synthesized via a two-step vacuum sintering method. X-ray diffraction and scanning electron microscopy were used to detect the phases presented in the composites and observe sample morphology. In addition, AC electrochemical impedance spectroscopy, cyclic voltammetry, along with constant current discharge/charge tests, were used to characterize the electrochemical properties of the composites. It was shown that LiFePO4/C with a single olive crystal structure could deliver discharge capacity of 145.5 and 108.7 mAh g(-1) at 0.5 and 6C for the fist cycle, and kept reversible capacity of 147.5 and 117.1 mAh g(-1) after 100 cycles. (C) 2010 Elsevier Ltd. All rights reserved.