ZnO-doped LiFePO4 cathode material for lithium-ion battery fabricated by hydrothermal method

•Zinc source is added into LiFePO4 precursor in the form of Zn(OH)2 solution.•ZnO help LiFePO4 form fine and even particles in the hydrothermal condition.•ZnO particles and Zn2+ ions act on the electrochemical performance of LiFePO4 together.

LiFePO4 particles doped with zinc oxide was synthesized via a hydrothermal route and used as cathode material for lithium-ion battery. Sample of preferable shape and structure was obtained by a concise and efficient process. ZnO doping into the LiFePO4 matrix was positively confirmed by the results of X-ray diffraction (XRD); high-resolution transmission electron microscopy (HRTEM); energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). LiFePO4 doped with ZnO tends to form nanometer-size and homogeneous particles, which can improve markedly the performance and stability of charge-discharge cycle. A specific discharge capacity of ZnO-doped LiFePO4 at 132.3 mAh g−1 was achieved, with 1.8% decrease after 100 cycles. Based on the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) results, it has further shown that ZnO doping effectively reduces the impacts of polarization and transfer resistance during electrochemical processes.