Journal of the Korean Crystal Growth and Crystal Technology (한국결정성장학회지)

The Korea Association of Crystal Growth (한국결정성장학회)
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Effects of doping on the electrical conductivity and particle size in olivine type $LiFePO_4$ powders

올리빈형 $LiFePO_4$ 분말의 전기전도도와 입도 크기에 미치는 도핑의 영향

  • Bai, Jin-Tao (Battery Research Center, Korea Institute of Science & Technology) ;
  • Ha, Jung-Soo (School of Materials Science & Technology, An-dong National University) ;
  • Kim, Chang-Sam (Battery Research Center, Korea Institute of Science & Technology)
  • 백진도 (한국과학기술연구원, 이차전지연구센터) ;
  • 하정수 (안동대하교, 재료공학과) ;
  • 김창삼 (한국과학기술연구원, 이차전지연구센터)
  • Published : 2008.12.31
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Abstract

To get a fine $LiFePO_4$ powder with high electrical conductivity, the influences of doping of aliovalent elements(Cr+B and Cr+Al) on electrical conductivity and of heat treatment conditions on particle size of the doped powders were studied. Two kinds of the doped powders $LiFe_{0.965}Cr_{0.03}B_{0.005}PO_4$ and $LiFe_{0.065}Cr_{0.03}Al_{0.005}PO_4$ were synthesized using mechanochemical milling and subsequent heat treatment at $675{\sim}750^{\circ}C$ for $5{\sim}10\;h$. The doping enhanced grain growth and electrical conductivity. The electrical conductivity at $30^{\circ}C$ was $1{\times}10^{-8}S/cm$ in the doped with Cr and Al, and $5{\times}10^{-10}S/cm$ in the undoped one.

전기전도성이 우수하면서 입자 크기가 작은 $LiFePO_4$ 분말을 얻기 위해서, 이종원소(Cr+B 또는 Cr+Al) 도핑이 $LiFePO_4$의 전기전도도에 미치는 영향과 열처리 조건이 입자 크기에 미치는 영향에 대해서 조사하였다. 조성이 $LiFe_{0.965}Cr_{0.03}B_{0.005}PO_4$ and $LiFe_{0.065}Cr_{0.03}Al_{0.005}PO_4$인 두 종류의 분말을 기계화학적 밀링법으로 혼합 후 $675{\sim}759^{\circ}C$에서 $5{\sim}10$시간 열처리하여 합성하였다. 이종원소 도핑은 입자성장을 촉진하였고 전기전도도를 높이는 효과가 있었다. $LiFe_{0.065}Cr_{0.03}Al_{0.005}PO_4$의 전기전도도는 $1{\times}10^{-8}S/cm$로 도핑하지 않은 것의 $5{\times}10^{-10}S/cm$보다 높았다.

Keywords

References

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