High throughtput compositional study of NMC cathode with lower cobalt concentration by CCS-sputtering

J-W Choi, J.S. Jung, H. Yim, N.S. Parmar, J-S Lee
Korea Institute of Science and Technology,
Korea

Keywords: continuous composition spread (CCS), NMC, sputtering system

Summary:

Today, all devices with lithium ion batteries (LIBs) are trending towards miniaturization and the easier portability. Extensive research on developing a new cathode material, a key component in LIBs, has been going on due to its higher capacity and power density as compared to the traditional cathode materials. Among cathode materials, even though Li(Ni, Mn, Co)O2 [NMC] composition is a fascinating cathode material due to its diverse possibilities of selection regarding to each applications, detail compositional study on NMC materials doesn’t exist yet. In this study, we explored a wide range of compositions of NMC cathode to choose the desired electrochemical performance by changing ratios of Ni to Mn at a small amount of Co concentration by continuous composition spread (CCS) sputtering method. Cathode composition was measured by Rutherford backscattering spectroscopy (RBS) and it shows that the optimized composition has better electrochemical performance. Reasons for its better electrochemical performance were further investigated by x-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), Fourier – transform infrared (FT-IR), and x-ray near edge spectroscopy (XANES).