Acta Phys. -Chim. Sin. ›› 2012, Vol. 28 ›› Issue (12): 2898-2904.

• ELECTROCHEMISTRY AND NEW ENERGY •

P123-Assisted Rheological Phase Reaction Synthesis and Electrochemical Performance of Li3V2(PO4)3/C Cathode

YUAN Zhi-Hong, MA Jun, CHEN Xing, LIU Kai-Yu

1. College of Chemistry & Chemical Engineering, Central South University, Changsha 410083, P. R. China
• Received:2012-07-29 Revised:2012-09-24 Published:2012-11-14
• Supported by:

The project was supported by the National Natural Science Foundation of China (21071153, 20976198).

Abstract:

A monoclinic Li3V2(PO4)3/C cathode has been synthesized for use in lithium ion battery applications via a P123-assisted rheological phase reaction (RPR) method. Li3V2(PO4)3/C composite materials were prepared from a mixture of V2O5, LiH2PO4, LiOH, citric acid, and triblock copolymer surfactant P123. The composite material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical performance was tested by Galvanostatic charge-discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The P123-assisted Li3V2(PO4)3/C assumes a pure monoclinic crystal structure and exhibits a high initial discharge capacity of 128.9 mAh·g-1, which only decreases by 0.9% of its initial value after 50 cycles at 0.1C between 3.0 and 4.3 V. Moreover, the cathode displays good fast rate performance, displaying discharge capacities of 128.2, 121.3, and 109.1 mAh·g-1 and capacity retentions after 50 charge-discharge cycles of 99.1%, 96.9%, and 90.7% at rates of 1C, 10C, and 25C, respectively. The introduction of the triblock copolymer surfactant P123 to the RPR system is attributed to the excellent electrochemical performance. It acts as a surfactant as well as an organic carbon source, and forms a carbon network in the particle surface, which helps improve the material conductivity rate, and reduce the charge transfer resistance and electrode polarity effects during the charge-discharge process.

MSC2000:

• O646