Journal of the Korean Electrochemical Society (전기화학회지)

The Korean Electrochemical Society (한국전기화학회)
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Manganese Doped LiFePO4 as a Cathode for High Energy Density Lithium Batteries

고에너지밀도 리튬전지를 위한 망간이 첨가된 LiFePO4 양극재료

  • Kim, Dul-Sun (Department of Materials Engineering and Convergence Technology, Department of Chemical & Biological Engineering, Gyeongsang National University) ;
  • Kim, Jae-Kwang (Department of Materials Engineering and Convergence Technology, Department of Chemical & Biological Engineering, Gyeongsang National University) ;
  • Ahn, Jou-Hyeon (Department of Materials Engineering and Convergence Technology, Department of Chemical & Biological Engineering, Gyeongsang National University)
  • 김둘선 (경상대학교 나노신소재융합공학과, 생명화학공학과) ;
  • 김재광 (경상대학교 나노신소재융합공학과, 생명화학공학과) ;
  • 안주현 (경상대학교 나노신소재융합공학과, 생명화학공학과)
  • Received : 2013.07.18
  • Accepted : 2013.08.12
  • Published : 2013.08.31
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Abstract

Porous $LiMn_{0.6}Fe_{0.4}PO_4$ (LMFP) was synthesized by a sol-gel process. Uniform dispersion of the conductive carbon source throughout LMFP with uniform carbon coating was achieved by heating a stoichiometric mixture of raw materials at $600^{\circ}C$ for 10 h. The crystal structure of LMFP was investigated by Rietveld refinement. The surface structure and pore properties were investigated by SEM, TEM and BET. The LMFP so obtained has a high specific surface area with a uniform, porous, and web-like nano-sized carbon layer at the surface. The initial discharge capacity and energy density were 152 mAh/g and 570 Wh/kg, respectively, at 0.1 C current density, and showed stable cycle performance. The combined effect of high porosity and uniform carbon coating leads to fast lithium ion diffusion and enhanced electrochemical performance.

다공성 $LiMn_{0.6}Fe_{0.4}PO_4$ (LMFP)를 졸-겔법을 이용하여 합성하였고, 원료물질을 양론비로 혼합한 후 혼합물을 $600^{\circ}C$에서 10시간 동안 가열하여 입자 표면 전체에 전도성 탄소물질이 균일하게 형성된 LMFP을 제조하였다. LMFP의 결정구조는 리트펠트법에 의해 조사하였고, 표면구조와 기공특성은 주사전자현미경, 투과전자현미경, BET로 분석하였다. 제조된 LMFP는 표면적이 크고, 입자 표면에는 웹(web) 형태의 다공성 탄소층이 균일하게 형성되어 있는 것을 확인하였다. 상온에서 LMFP를 양극으로 사용하여 0.1 C의 전류밀도에서 초기방전용량은 152 mAh/g, 에너지밀도는 570 Wh/kg로 높았고 사이클 성능도 장기적으로 안정적이었다. 졸-겔법에 의해 제조된 LMFP는 높은 기공도와 균일한 탄소코팅에 의한 시너지효과로 이온확산이 용이하여 우수한 전기화학적 특성을 나타내었다.

Keywords

References

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