Synthesis and Performance of LiFexMn1-xPO4/C as Cathode Material for Lithium Ion Batteries

LiFe Mn1-xPO4/C composites were synthesized by a solid-state reaction route using phenolic resin as both reducing agent and carbon source. The effect of Fe doping on the crystallinity and electrochemical performance of LiFexMnt xPOJC was investigated. The experimental results show that the Fe2＋ substitution for Mn2＋ will lead to crystal lattice shrinkage of LiFe Mn1-xPO4/C particles due to the smaller ionic radii of Fe2＋ In the investigated Fe doping range （x = 0 to 0.7）, LiFe Mn1-xPO4/C （x = 0.4） composites exhibited a maximum discharge capacity of 148.8 mAh/g at 0.1 C while LiF%MnI_xPO4/C （x = 0.7） composite showed the best cycle capability with a capacity retention ratio of 99.0% after 30 cycles at 0.2 C. On the contrary, the LiFe Mnl-xPO4/ C （x = 0.5） composite performed better trade-off on discharge capacity and capacity retention ratio, 127.2 mAh/ g and 94.7% after the first 30 cycles at 0.2 C, respectively, which is more preferred for practical applications.