1. 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

2. 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.

3. XRD SEM

4. 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 3.0-4.3 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 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%

5. 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

6. 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 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.

7. Thank you!