Study on Vanadium Substitution to Iron in Li2FeP2O7 as Cathode Material for Lithium-ion Batteries

Abstract

Dou, S. (2014). Study on vanadium substitution to iron in Li2FeP 2O7 as cathode material for lithium-ion batteries. Electrochimica Acta, Study on vanadium substitution to iron in Li2FeP 2O7 as cathode material for lithium-ion batteries AbstractA series of Li2Fe1-3x/2VxP 2O7 (x = 0, 0.025, 0.05, 0.075, and 0.1) cathode materials for LIBs were prepared by the sol-gel method. Structural characterization of Li2Fe1-3x/2VxP2O7 (x = 0, 0.025, 0.05, 0.075, and 0.1) samples was conducted by synchrotron X-ray diffraction. The morphology and oxidation states of Fe2+ and V 3+ in the Li2Fe1-3x/2VxP 2O7 samples were confirmed by scanning electron microscopy and magnetic susceptibility measurements, respectively. The electrochemical measurements indicated that Li2Fe1-3x/2VxP 2O7 (x = 0.025) delivered the higher reversible capacity of 79.9 mAh g-1 at 1 C in the voltage range of 2.0 -4.5 V with higher 77.9% capacity retention after 300 cycles than those of Li 2FeP2O7 (48.9 mAh g-1 and 72.6%). Moreover, the rate capability of Li2Fe1-3x/2V xP2O7 (x = 0.025) were also significantly enhanced through vanadium substitution to iron of Li2Fe 1-3x/2VxP2O7. The vanadium substituted to Fe2 site of Li2FeP2O7 decreases Li occupying the Li5 position in the FeO5 unit, leading to a low degree exchange between Li and Fe in the MO5 (M = Li and Fe). The low degree cation disorder was beneficial to lithium-ion extraction/insertion during the charge-discharge process and hence enhances the capacity and rate capability. The low degree cation disorder was beneficial to lithium-ion extraction/insertion during the charge-discharge process and hence enhances the capacity and rate capability.1

Growth of NiCo2O4@MnMoO4 Nanocolumn Arrays with Superior Pseudocapacitor Properties

“…The equivalent circuit diagram fitting the EIS plots is also presented. The equivalent model includes the Warburg impedance of diffusive resistance ( W ), the charge-transfer resistance ( R ct ), and the bulk solution resistance ( R s ) . Therein, R ct is the key indicator of kinetics.…”

Structural and electrochemical properties of the Li2FeP2O7/C composite prepared using soluble methylcellulose

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Design and Fabrication of Petal-Like NiCo2O4@NiMoO4Core/Shell Nanosheet Arrys Electrode for Asymmetric Supercapacitors

“…Electrochemical impedance spectroscopy (EIS) is used to investigate the electrode material in the electrochemical reaction of charge transport and ion diffusion. 58,59 The semicircle indicates the charge transfer resistance at the surface of the electrode. As can be seen from Fig.…”