Modification of a LiFePO₄ cathode for lithium ion batteries by carbon coating and copper doping

The effects of a carbon coating and copper doping on the electrochemical performance and tap density of a LiFePO₄ cathode for lithium ion batteries were investigated by XRD, SEM, charge/discharge cycle tests, rate tests and tap density tests. Results showed that the average discharge capacity of LiFePO₄/C and LiFe_0.95Cu_0.05PO₄ were 147 mAh/g and 131 mAh/g respectively. The capacity fading rate of LiFe_0.95Cu_0.05PO₄ was much larger than that of LiFePO₄/C in a high-rate discharging test. The electrochemical performance of LiFePO₄/C was better than that of LiFe_0.95Cu_0.05PO₄, but the tap density of the latter was 1.5 times as large as that of the former.