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Vanadyl phosphates of VOPO4 as a cathode of Li-ion rechargeable batteries

Bustam, Mohamad Azmi and Ishihara, Tatsumi and Nishiguchi, Hiroyasu and Yusaku, Takita (2003) Vanadyl phosphates of VOPO4 as a cathode of Li-ion rechargeable batteries. [Citation Index Journal]

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Abstract

Seven phases of VOPO4 were synthesized and their Li intercalation properties were investigated. Li can be reversibly intercalated into all phases of VOPO4 and potential plateaus for Li intercalation and de-intercalation exist at 3.7 and 3.9 V, respectively, except for the b- and e phases. b- and e-phases of VOPO4 exhibit slightly higher flat potentials of 3.9 and 4.1 V. The capacity for Li intercalation is strongly affected by the crystal structure of VOPO4 and the Li intercalation capacity increases with increasing average valence of V. Among the VOPO4 crystal phases, it was found that the d-phase exhibits the largest reversible capacity of ca. 130 mAh/g. The capacity for Li de-intercalation in d-phaseVOPO4 hardly decreased over 35 charge and discharge cycles. On the other hand, the Li intercalation capacity in d-phase VOPO4 decreased with increasing current density for charge and discharge and temperature. However, even at a current density of 0.4 mA/cm2, corresponding to C/5, fairly large capacity of ca. 60 mAh/g was sustained, and at a operating temperature or 323 K, a capacity of 110 mAh/g was exhibited at 0.04 mA/cm2.

Item Type:Citation Index Journal
Subjects:T Technology > T Technology (General)
Departments / MOR / COE:Departments > Chemical Engineering
ID Code:3801
Deposited By: Assoc Prof Dr Mohamad Azmi Bustam @ Khalil
Deposited On:04 Jan 2011 00:36
Last Modified:19 Jan 2017 08:27

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