In this paper, a simple one-step doping spray method using liquid polyacrylonitrile (LPAN) is reported, for the preparation of LiNi0.8Co0.15Al0.05O2 (NCA) precursor, after calcination, to obtain a loose and porous sphere-shaped NCA (LPAN@NCA). The initial discharge specific capacity was found to be 227.9 mA h g−1 at 0.1C, which is 26.6% higher than that of the pristine sample. Its capacity retention rate was found to be 93.59% after 200 cycles, and the surface morphology of the material grains after the cycles remains intact. X-ray diffraction (XRD) analysis reveals that doping with LPAN can effectively decrease the amount of disorder of Ni2+ in Li + position that gets reduced by 2.72%. The X-ray photoelectron spectroscopy (XPS) analysis shows that after the carbonization of LPAN, the C atoms replace part of O atoms, effectively forming a new compound. The decrease in the impedance of the battery materials before and after the cycle and the increase of lithium ion mobility also confirms the effectiveness of LPAN doping. The LPAN@NCA prepared by in-situ doping of LPAN by spraying method is simple and effective, which exhibits high specific capacities, superior rate performance and excellent recycling stability, that has a good commercial application prospect.