Revealing electrochemical performance of Ni doping LiFePO4 composite.

In this work, Ni2+ was doped into the crystal lattice of LiFePO4 to improve the electrochemical performance. Lengths of the Li–O bonds in LiFe0.98Ni0.02PO4/C (2% NiSO4-doped LiFePO4) is longer than that of the bare LiFePO4 sample, the micromorphology of LiFe0.98Ni0.02PO4/C sample becomes uniform, and the Ni2+ doped into LiFePO4 expands the crystal plane spacing, which is conducive to Li+ diffusion. Amongst all the doped samples, the Li+ diffusion coefffcient of LiFe0.98Ni0.02PO4/C is the largest, and the redox peak of LiFe0.98Ni0.02PO4/C is more symmetrical, sharper and narrower, indicating that the proper amount of Ni2+-modified LiFePO4 can improve the electrochemical performance. Specific discharge capacity at 1C is 152 mAh g−1 when the doping amount is 2%. Additionally, after 200 cycles at 2C, the discharge specific capacity can be attained at 140 mAh g−1 and capacity retention rate reached 98%. [ABSTRACT FROM AUTHOR]