LiFePO4 is considered an environmentally friendly, popular cathode material for lithium ion batteries because of its low raw materials cost, non-toxicity, and excellent thermal stability. The antimony(Sb)-doped LiFePO4/C materials are successfully synthesized by a high-temperature solid-state method in this work. The effects of Sb concentration and synthesized temperature are reported. The sample doped with 1.0 mol.% Sb and synthesized at 873 K delivered the best discharge capacity of 154 mAh g-1 at a 0.2 C-rate. Furthermore, the LiFe0.99Sb0.01PO4/C materials synthesized at 973 K can sustain a 28 C-rate between 4.6 and 2.0 V, and this rate capability is equivalent to charge or discharge in 129 seconds. The doped cathode materials are also characterized by a XRD technique for structure analysis.