The Contribution of Calcium Ion Doping To the Rate Property for Life0.5mn0.5po4/C

Abstract

Exotic atom doping is one of the crucial measures to improve the electrochemical activity of cathode materials. The calcium-doped LiFe0.5Mn0.5PO4@C (LFMP/C-Ca) can be successfully prepared by high temperature solid-state reaction. The XRD Rietveld refinement results show that calcium ion doping increases the lattice parameters of the LFMP/C. Compared to LFMP/C, the LFMP/C-3Ca exhibits excellent cycling stability and rate performance. The GITT results show that LFMP/C-3Ca possesses a larger lithium-ion diffusion coefficient than LFMP/C. Based on density function theory (DFT) calculations and experiment analysis, it has been confirmed that the LFMP/C-3Ca possesses a superior electronic conductivity. At high rates, the discharge specific capacities of LFMP/C-3Ca are 105.7 mAh g-1, 94.7 mAh g-1, 84.9 mAh g-1, 70.8 mAh g-1 and 53.1 mAh g-1 at 10 C, 20 C, 30 C, 40 C, 50 C, respectively. Therefore, the appropriate calcium doping is helpful to improve rate performance of LiFe0.5Mn0.5PO4@C.

Keywords: calcium doping, LiFe0.5Mn0.5PO4, electronic conductivity, high-rate performance, Lithium-ion batteries