WEB Physicochemical and Electrochemical Studies of Carbon Coated LiNi0.6Mn0.2Co0.2O2 Cathode Material in Lithium Battery ConfigurationTuesday (22.09.2020) 15:00 - 15:15 F: Functional Materials, Surfaces, and Devices 1 Part of:
The high-nickel NMC (LiNixMnyCozO2, x+y+z=1; where, x≥0.6) is regarded as promising cathode active material for next generation Li-ion batteries due to their ability to deliver high specific capacities. However, their capabilities are restricted by the unwanted side reactions with the electrolyte leading to decomposition on the surface of the particles at high voltage (> 4.2 V vs. Li+/Li). This also leads to structural degradation on the surface and limited cycling performance . Surface coating is a prevalent strategy to minimize side reactions that occur on the surface preventing material degradation . Due to high electronic conductivity and stability of carbon against electrolytes at higher voltages, this study presents for the first time a carbon-coated LiNi0.6Mn0.2Co0.2O2(NMC622/C) material via polymerization using furfuryl alcohol as monomers on the surface of NMC particles followed by a carbonization step. This simple mixing approach for the coating process opens up the possibility of an easy implementation in industrial processes. Numerous analytical techniques were performed to characterize the coated materials, i.e. Thermogravimetric Analysis (TGA) to understand the kinetics during carbonization, in-situ High-Temperature X-Ray Diffraction (HT-XRD) to monitor the phase changes, Scanning and Transmission Electron Microscopy (SEM & TEM) were used to observe the morphology of the particle. Fourier-Transform Infrared (FT-IR) spectroscopy to observe the presence of polymerization and the carbon in the sample, CHNS(O) analysis to quantify the amount of carbon in the sample after the heat treatment step. Furthermore, electrochemical; analysis such as cyclic voltammetry, charge-discharge and rate capability tests were carried out to investigate the impact of the carbon coating on the electrochemical performance and structure stability of the material during cycling. The results from the XRD show no phase change in the sample after the pyrolysis, SEM and TEM show the homogenous coating of the carbon on top of the NMC and FT-IR shows the presence of the carbon bonds on the pyrolyzed samples, TGA results show the decomposition of the polymer ~240oC and formation of carbon. Further, the rate capability tests show higher capacity in the coated samples.