Journal of the Korean Electrochemical Society (전기화학회지)

The Korean Electrochemical Society (한국전기화학회)
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PH Effect of [Li,La]TiO3 Coating Solution on Electrochemical Property of Li[Ni0.35Co0.3Mn0.35]O2 Cathode

[Li,La]TiO3 코팅용액의 pH에 따른 Li[Ni0.35Co0.3Mn0.35]O2 양극의 전기화학적 특성

  • Jung, Kwang-Hee (Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology) ;
  • Kim, Seuk-Buom (Department of Advanced Materials Engineering, Kyonggi University) ;
  • Park, Yong-Joon (Department of Advanced Materials Engineering, Kyonggi University)
  • 정광희 (한국과학기술원 신소재공학과) ;
  • 김석범 (경기대학교 신소재공학과) ;
  • 박용준 (경기대학교 신소재공학과)
  • Received : 2011.03.03
  • Accepted : 2011.04.29
  • Published : 2011.05.31
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Abstract

The surface of $Li[Ni_{0.35}Co_{0.3}Mn_{0.35}]O_2$ cathode was modified by $[Li,La]TiO_3$ coating using pH controlled coating solution. At low pH values (acidic solution), cathode powders, which is oxides, have a positive surface charge, whereas, they have a negative surface charge at high pH values. As a result, their charge could affect the formation of the coating layer on the surface of cathode powder. To determine the optimal pH value, the surface coating of the pristine powder was carried out at various pH values of the coating solution. The surface morphology of coated samples was characterization by SEM and TEM analyses. Impedance analysis and cyclic voltammogram presented that internal resistance of the cell was dependent upon the pH of coating solution.

[Li,La]$TiO_3$ 코팅용액의 pH를 조절하여 이에 따른 코팅된 $Li[Ni_{0.35}Co_{0.3}Mn_{0.35}]O_2$ 양극활물질의 전기화학적 특성을 관찰하였다. 산화물인 양극분말은 접촉하고 있는 용액의 pH에 따라 표면 전하를 띄게 되는데 양이온인 코팅물질을 균일하게 반응시키기 위해서는 적절한 pH 조절을 통해 양극분말 표면을 음전하 상태로 조절해 주는 것이 필요하다. SEM, TEM 분석을 통해 코팅용액의 pH에 따른 코팅층의 형상변화를 관찰하였으며 다양한 전류밀도로 충전과 방전을 실시하여 코팅용액의 pH에 따른 방전용량, 사이클 특성, 고율특성을 분석하였다. 임피던스잴 cyclic voltammogram 측정을 통해 코팅용액의 pH에 따른 코팅층의 내부저항 변화를 관찰하였으며 이것을 전기화학적 특성과 연관됨을 확인하였다.

Keywords

References

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