Synthesis of LiFe1-xNixPO4/C composites and their electrochemical performance

Authors

Yang Lu, Fujian University, China
Jichen Shi, Fujian University, China
Zaiping Guo, University of WollongongFollow
Qinsong Tong, Fujian University, China
Weijing Huang, Fujian University, China
Bianyun Li, Fujian University China

RIS ID

31437

Publication Details

Lu, Y, Shi, J, Guo, Z, Tong, Q, Huang, W & Li, B (2009), Synthesis of LiFe1-xNixPO4/C composites and their electrochemical performance, Journal of Power Sources, 194(2), pp. 786-793.

Abstract

LiFePO₄/C and LiFe_1−xNi_xPO₄/C (x = 0, 0.02, 0.04, and 0.06) composites were prepared using solid-state reaction. The as-prepared composites were characterized by using X-ray diffraction, charge–discharge cycling, cyclic voltammograms, Raman spectroscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and other techniques. The experimental results show that all as-prepared composites have a single phase of orthorhombic olivine-type structure with the Pnmb space group. The as-prepared LiFe_1−xNi_xPO₄/C composites exhibit high capacities and good cycling performance; e.g., the LiFe_0.98Ni_0.02PO₄/C composite delivers 142 and 138 mAh g⁻¹ at the 0.1 C rate for the first and fifth cycles, respectively. Such composites also show good rate capabilities; e.g., when discharged at the 2 C rate the LiFe_0.98Ni_0.02PO₄/C composite delivers an initial capacity of 121 mAh g⁻¹, 85% of the discharge capacity at the 0.1 C rate. The reason why the LiFe_1−xNi_xPO₄/C composites have better electrochemical performance compared to the LiFePO₄/C composites is because nickel doping enhances the PO bond, stabilizes the structure, and thus the charge-transfer resistance and cathode particle resistance of the composites are decreased.