Study on the dominant film-forming site among components of Li(Ni 1/3Co1/3Mn1/3)O2 cathode in Li-ion batteries

Abstract

Surface film formation on Li(Ni1/3Co1/3Mn 1/3)O2 cathodes upon oxidation of electrolyte during electrochemical cycling was investigated. Information on the important factors for film formation on the cathode can facilitate the design of additives that improve the properties of the cathode. Pyrazole is added to the electrolyte because it is readily oxidized to form a surface film on the cathode. The results of differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR) showed that the active material played a dominant role in the interfacial film formation with the electrolyte. Carbon black played a negligible role in the surface film formation.