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Effect of Sulfate-based Cathode-Electrolyte Interphases on Electrochemical Performance of Ni-rich Cathode Material

  • Chae, Bum-Jin (Department of Chemistry, Incheon National University) ;
  • Song, Hye Ji (Department of Chemistry, Incheon National University) ;
  • Mun, Junyoung (Department of Energy and Chemical Engineering, Incheon National University) ;
  • Yim, Taeeun (Department of Chemistry, Incheon National University)
  • 투고 : 2020.03.06
  • 심사 : 2020.06.18
  • 발행 : 2020.11.30

초록

Recently, layered nickel-rich cathode materials (NCM) have attracted considerable attention as advanced alternative cathode materials for use in lithium-ion batteries (LIBs). However, their inferior surface stability that gives rise to rapid fading of cycling performance is a significant drawback. This paper proposes a simple and convenient coating method that improves the surface stability of NCM using sulfate-based solvents that create artificial cathode-electrolyte interphases (CEI) on the NCM surface. SOx-based artificial CEI layer is successfully coated on the surface of the NCM through a wet-coating process that uses dimethyl sulfone (DMS) and dimethyl sulfoxide (DMSO) as liquid precursors. It is found that the SOx-based artificial CEI layer is well developed on the surface of NCM with a thickness of a few nanometers, and it does not degrade the layered structure of NCM. In cycling performance tests, cells with DMS- or DMSO-modified NCM811 cathodes exhibited improved specific capacity retention at room temperature as well as at high temperature (DMS-NCM811: 99.4%, DMSO-NCM811: 88.6%, and NCM811: 78.4%), as the SOx-based artificial CEI layer effectively suppresses undesired surface reactions such as electrolyte decomposition.