Acta Phys. -Chim. Sin. ›› 2004, Vol. 20 ›› Issue (06): 582-586.doi: 10.3866/PKU.WHXB20040606

• ARTICLE • Previous Articles     Next Articles

Effect on the Electrochemical Performance of Lithium Iron Phosphate by Cr3+ Ion Doping

Ni Jiang-Feng;Zhou Heng-Hui;Chen Ji-Tao;Su Guang-Yao   

  1. College of Chemistry and Molecular Engineering, Peking University, Beijing 100871;College of Chemistry, Xiangtan University, Xiangtan 411105
  • Received:2003-12-10 Revised:2004-02-05 Published:2004-06-15
  • Contact: Zhou Heng-Hui

Abstract: Two different methods(mechanical ball-milling and co-precipitation)were applied to prepare lithium iron phosphate(LiFePO4) containing low concentration(1%, mole fraction) Cr3+ ion dopant. The samples were characterized by X-ray diffraction and scanning electron microscope, and their electrochemical performances were investigated including cycling behavior and large current discharging. The results indicate that the Cr3+ ion dopant does not affect the structure of the material but considerably improves its kinetics in terms of capacity delivery and cycle performance. At a low discharging rate (0.1 C), LiFePO4 samples doping via mechanical ball-milling and co-precipitation are capable of delivering reversible specific capacities of 144 mAh•g-1 and 158 mAh•g-1 respectively, with fairly stable cycleability. Even at a 2 C discharging rate, they can show capacities of 110 mAh•g-1 and 130 mAh•g-1 respectively, too. The results also confirm that doping via co-precipitation with Fe sources is an effective method to improve the ion doping effect.

Key words: Lithium iron phosphate, Co-precipitation, Ion doping, Electronic conductivity, Lithium intercalation capacity, Positive electrode material