Improvement of electrochemical performance for Li3V2(PO4)3/C electrode using LiCoO2 as an additive

指导教师：唐致远教授学生：王利娟

1. Experimental1. ExperimentalThe LVP/C composite material was synthesized by a sol-gel method based on composite chelating reagents using LiOH·H2O (A.R.), NH4VO3 (A.R.), NH4H2PO4 (A.R.), C2H2O4·2H2O (oxalic acid, A.R.), C2H5NO2 (glycine, A.R.) and beta-cyclodextrin as raw materials.

For the fabrication of the cathode electrodes, 85 wt.% active material was ball-milled with 10 wt.% acetylene black and 5 wt.% polyvinylidene difluoride (PVDF) or 82 wt.% active material was ball-milled with 3 wt.% commercial lithium cobalt oxide LiCoO2 obtained from Pulead Technology Industry Co., Ltd, 10 wt.% acetylene black

and 5 wt.% polyvinylidene difluoride (PVDF) in an appropriate amount of N-methyl-2-pyrrolidine for 5 h to form slurry. Then the slurry was pasted onto the aluminum current collectors and the electrodes were dried at 120 ℃ in vacuum for 12 h. The obtained electrodes were denoted as LVP/C electrode and LVP/LCO/C electrode, respectively. The cion-type cells were assembled in a glove box filled with high purity argon.

XRDSEM

SEM

Fig. 2.and discharge curves of Li3V2(PO4)3/ LiCoO2/C electrode at various charge and discharge rates in the range of 3.0-4.3 V.

Fig. 3 Cyclic performance of Li3V2(PO4)3/ LiCoO2/C electrode at various charge and discharge rates in the range of 3.0-4.3 V.

LVP/LCO/C 电极在 55C 放电电流下循环 800 次，容量保持率接近

90%

Fig. 4 Impedance spectra of Li3V2(PO4)3/C and Li3V2(PO4)3/ LiCoO2/C electrodes at different cycles.

与 LVP/C 电极 相比， LVP/LCO/C 电极具有较小的电荷转移阻

抗

3.Conclusions3.Conclusions ：：1) A new Li3V2(PO4)3/C electrode using LiCoO2 as an additive (LVP/LCO/C) has been successfully fabricated.

2) The electrode presents excellent rate capability and cyclic performance in the range of 3.0-4.3 V, which are attributed to the small particles, narrow particle size distribution in the LVP/LCO/C electrode, and low electrical resistance for the electrode.

3) It is a simple and effective method of improving the electrochemical performance of the LVP/C via adding additive in

the fabrication of the electrode. The LVP/LCO/C is a promising cathode electrode candidate for high-power lithium ion batteries.

Thank you!