Electrochemical Property Investigation of Cobalt Doped LiFePO4/C during Charge-Discharge by an In-situ X-Ray Near Edge Structure Technique.

LiFePO₄/C and LiFe_0.9Co_0.1PO₄/C materials were synthesized via a solid state method. 10% cobalt was chosen as a doping element in the Fe-site of LiFePO₄/C to increase its electronic conductivity. The crystal structure and particle morphology of this material were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, respectively. The electrochemical mechanism observed during cycling of a LiFe_0.9Co_0.1PO₄/C electrode was investigated using in-situ time resolved X-ray absorption near edge structure (in-situ XANES). The experimental results showed that the electrochemical mechanism of LiFe_0.9Co_0.1PO4/C mainly took place with the Fe²⁺/Fe³⁺ redox couple. The Co²⁺/Co³⁺ couple redox was not active during cycling. The Co doped sample had an improved crystal structure, resulting in a higher energy density than LiFePO₄/C. [ABSTRACT FROM AUTHOR]