Sol-gel synthesis of nano Li1.2Mn0.54Ni0.13Co0.13O2 cathode materials using DL-lactic acid as chelating agent

Lithium-rich cathode materials Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) are prepared by sol-gel method using DL lactic acid as chelating agent. The effect of pH on crystal structures, morphologies, particle sizes, and electrochemical properties of cathode materials are studied by X-ray diffractometry (XRD), scanning electron microscopy (SEM), nanoparticle analysis, charge-discharge tests, and electrochemical analysis. The Li1.2Mn0.54Ni0.13Co0.13O2 cathodes exhibit well-ordered layered structures consisting of hexagonal LiMO2 and monoclinic Li2MnO3 with smooth surfaces and well-crystallized particles (100-500 nm). LMNCO-7.0 exhibits smaller particle sizes than LMNCO-5.5 and LMNCO-8.5 and better electrochemical performance. The first discharge capacity and Coulombic efficiency of LMNCO-7.0 are 232.31 mAh g(-1) and 73.2%, respectively. After 50 cycles, discharge capacity of LMNCO-7.0 decrease to 194.93 mAh g(-1). LMNCO-7.0 cathode shows superior discharge capacity and rate performance due to its low charge transfer impedance and small average quasi spherical particle diameter.

Automated summary

The research shows that lithium-rich cathode materials Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO), prepared by the sol-gel method with DL lactic acid as the chelating agent, demonstrate excellent crystal structure and electrochemical performance. Among LMNCO-5.5, LMNCO-7.0, and LMNCO-8.5, LMNCO-7.0 exhibits smaller particle sizes and better electrochemical properties. The first discharge capacity of LMNCO-7.0 is 232.31 mAh g(-1), decreasing to 194.93 mAh g(-1) after 50 cycles.