Electrochemical enhancement of LiFePO4 as a cathode material by incorporating Cu flakes for lithium ion rechargeable battery

The demand for power sources for electric vehicles (EV) and hybrid electric vehicles (HEV) with high-specific energy has brought immense interest in LiFePO4 (LFP) as a cathode for lithium ion batteries. However, intrinsically poor conductivity of LFP has hindered the realization of its high theoretical capacity (170 mAh g− 1). In order to improve the electric conductivity of LFP cathode, Cu flakes with very high surface area was incorporated in the cathode by ball milling Cu flakes. Uniformly dispersed Cu flakes subsequently transformed to CuO during the calcination process. The Cu incorporated LFP composite cathode showed a high capacity of 161 mAh g− 1, displayed excellent high rate and cyclic performance. The capacity loss was less than 15% at a discharge rate of 2C and less than 1% after 50 cycles at C/10 rate. The cathode composite was characterized using X-ray diffraction (XRD), Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Micro-Raman, and specific surface area. Electrochemical properties were measured using electrochemical impedance spectroscopy (EIS), potentiostatic intermittent titration technique (PITT) and galvanostatic measurements.

► LiFePO4/Cu/C composite is compared with bare LiFePO4 and LiFePO4/C. ► Cu flakes used as catalyst for transformation of C lead to high amounts of graphene. ► Higher amounts of graphene and Cu co-coating reduce charge transfer resistance. ► Increase in electronic conductivity leads to enhanced electrochemical properties.