Effect of Trace Al Surface Doping on the Structure, Surface Chemistry and Low Temperature Performance of LiNi0.5Co0.2Mn0.3O2 Cathode

Effect of trace Al surface doping on the structure, surface chemistry and low temperature performance of LiNi0.5Co0.2Mn0.3O2 cathode is studied. Trace Al surface doping significantly promotes the low temperature performance of LiNi0.5Co0.2Mn0.3O2. At −20 °C, the discharge capacity of the bare LiNi0.5Co0.2Mn0.3O2 is 37.8 mAh g−1 at 5C, while it increases to 60.5 mAh g−1 after trace Al surface doping, nearly twice magnitude of the bare material. Via the X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscopy analysis, it is confirmed that Al element has been successfully doped into the surface of LiNi0.5Co0.2Mn0.3O2. Surface-doped trace Al efficiently changes the lattice parameters, inhibits the resistance rise, accelerates lithium ion diffusion, and finally promotes the low temperature performance of LiNi0.5Co0.2Mn0.3O2.