Ni-doping to improve the performance of LiFeBO₃/C cathode material for lithium-ion batteries

Ni-doping is used to improve the performance of LiFeNiBO₃/C for the first time. The structure and electrochemical properties of as-prepared Ni-doped samples (LiFe_1-xNi_xBO₃/C) are investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscope, electrochemical impedance spectroscopy, and galvanostatic charge-discharge tests. The results show that LiFe_1-xNi_xBO₃/C composites consisted of similar spherical particles are linked and well-coated by nano-carbon frameworks, forming a multi-layer core-shell structure. Moreover, the substitution content of iron by nickel has significant effect on the electrochemical characteristics, especially for the rate performance. Particularly, the LiFe_0.94Ni_0.06BO₃ shows the best electrochemical property, exhibiting a discharge capacity of 201.5 mAh g⁻¹ at a current density of 10 mA g⁻¹. The results indicate that Ni doping in LiFeBO₃/C can effectively enhance the electrochemical performance, especially at a high charge/discharge rate.