Effect of Al and Zr co-doping on electrochemical performance of cathode Li[Li0.2Ni0.13Co0.13Mn0.54]O2 for Li-ion battery

The Li[Li0.2Ni0.13-x + y/3Co0.13-x + y/3Mn0.54-x + y/3]Al (x) Zr (y) O-2 was synthesized via conventional solution combustion synthesis method. X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrochemical experiment were used for material characterization and evaluation of powder morphology and electrochemical performance. According to XRD and SEM results, Zr-Al was successfully synthesized and it was inserted into crystal lattice. In addition, Zr-Al co-substitution distributed uniformly in Li[Li0.2Ni0.13Co0.13Mn0.54]O-2. The results indicate that by addition of Zr, lattice parameters a and c are increased and lattice volume becomes larger. Addition of Al improves structural stability of cathode materials. The sample with Al (x = 0.02) and Zr (y = 0.015) exhibited high discharge capacity and best cycling performance. The Li[Li0.2Ni0.13Co0.13Mn0.54](0.965)Al0.02Zr0.015O2 showed higher cycling stability and higher capacity in comparison with those of non-substituted material. The initial discharge capacity for Zr-Al co-doped electrode was 245.5 mAh g(-1) at 25 mA g(-1), and capacity retention was 98% after 50 cycle. While, the initial discharge capacity for bare electrode was 239.1 mAh g(-1) at 25 mA g(-1), and capacity retention was 93% after 50 cycle. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) revealed that by addition of Zr-Al ingredients, electrochemical performance of the Li[Li0.2Ni0.13Co0.13Mn0.54]O-2 is improved.