Mn-doped LiFePO4./C composite with excellent high-rate performance as lithium ion batteries cathode

Abstract

Nano-rod Mn-doped carbon coating LiFePO4 composites have been synthesized by a sample solvothermal process coupled with calcination, which shows an excellent performance at high rate condition. The morphology and microstructure of the composites were evidenced by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The electrochemical properties were evaluated by constant current charge/discharge test. Mn-doping magnified the interplanar spacing, providing a smoother aisle for ionic transport, it is beneficial to improve electrochemical properties at high rate. The stability was enhanced as well combined with carbon coating. In electrochemical measurement of the specific charge capacity, rate capacity and cycling stability, the obtained composite rod-like materials offer remarkably promising results for application, the initial discharge capacity is 160 mAh·g-1 at 0.2 C and 120 mAh·g-1 at 10 C, the capacity retention ratio is 94% at 0.2 C and 93% at 10 C after 50 charge-discharge cycles.