Improvement of synthesis method for LiFePO4/C cathode material by high-frequency induction heating

Abstract

The present LiFePO4/C cathode material is synthesized via carbothermal reduction by a high-frequency induction heating method in extremely short heating time (within a few minutes). The electric conductivity of LiFePO4/C is improved to 1.9 × 10-2S cm-1 by a short-time annealing process following a sintering process at 900°C. An increase in the particle size and formation of Fe2P as impurity are suppressed by annealing at a relatively low temperature: 700°C. The cathode containing annealed LiFePO4/C shows discharge capacities of 156.0, 136.3, and 100.1 mAhg-1 at 1/10, 1, and 10 C-rates (1C = 170mAg-1), respectively, and its polarization between charge and discharge is smaller than that of non-annealed LiFePO4/C. Furthermore, the annealed LiFePO4/C cathode shows better charge and discharge rate performance than the non-annealed LiFePO4/C cathode. © The Electrochemical Society of Japan, All rights reserved.