Indexed on: 23 Dec '18Published on: 18 Dec '18Published in: Ionics
A series of layered Li[Li0.2Mn0.54Ni0.13Co0.13]O2 cathode materials, of which manganese source was electrolytic manganese dioxide, with different contents of SO4 2− were successfully synthesized via ball-milling process and solid-state sintering method. The obtained materials were characterized by XRD, XPS, SEM-EDS, C-S, ICP, and HR-TEM. All the obtained materials presented well-ordered layered structure. When the content of SO4 2− was below 1.30 wt%, the electrochemical properties and structural stabilities at low rate for the layered materials with SO4 2− were not changed dramatically, while when the content of SO4 2− increased to 5.85 wt%, the initial discharge capacities decreased dramatically from 248.24 to 209.23 mAh g−1 at 10 mA g−1. And the pristine sample shows excellent cyclic property and rate capability. It delivered the discharge capacity of 175.25 mAh g−1 after 100 cycles with the highest capacity retention of 90.67% at 200 mA g−1. Particularly, the treated Li-rich Mn-based materials with the highest amount of SO4 2− exhibited the best cyclic stability and it delivers the highest capacity retention of 95.17% after 100 cycles at 200 mA g−1. However, its discharge capacities were much lower than the pristine material. As a result, the addition of SO4 2− could promote side reactions between electrode and electrolyte and deep-degree corrosion of electrode materials to affect the electrochemical properties and structural stabilities of the Li-rich Mn-based materials.