Improvement of electrochemical performance for Li 3 V 2 (PO 4 ) 3 /C electrode using LiCoO 2 as an additive 指导教师：唐致远教授 学生：王利娟

1. Experimental The LVP/C composite material was synthesized by a sol-gel method based on composite chelating reagents using LiOH·H 2 O (A.R.), NH 4 VO 3 (A.R.), NH 4 H 2 PO 4 (A.R.), C 2 H 2 O 4 ·2H 2 O (oxalic acid, A.R.), C 2 H 5 NO 2 (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 LiCoO 2 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.

XRD SEM

Fig. 2.and discharge curves of Li 3 V 2 (PO 4 ) 3 / LiCoO 2 /C electrode at various charge and discharge rates in the range of V. Fig. 3 Cyclic performance of Li 3 V 2 (PO 4 ) 3 / LiCoO 2 /C electrode at various charge and discharge rates in the range of 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 Li 3 V 2 (PO 4 ) 3 /C and Li 3 V 2 (PO 4 ) 3 / LiCoO 2 /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.Conclusions ： 1) A new Li 3 V 2 (PO 4 ) 3 /C electrode using LiCoO 2 as an additive (LVP/LCO/C) has been successfully fabricated. 2) The electrode presents excellent rate capability and cyclic performance in the range of 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!