High‐Rate and Long‐Life Au Nanorods/LiFePO<sub>4</sub> Composite Cathode for Lithium‐Ion Batteries
Xinyue Wang, Chi Chen, Shaoping Wu, Hongpeng Zheng, Yujie Chen, Hezhou Liu, Yongming Wu, Huanan Duan
Abstract
LiFePO 4 is considered a promising cathode material for lithium‐ion batteries for its high theoretical specific capacity and cycling stability. However, low electrical conductivity and Li‐ion diffusion coefficient limit its electrochemical performances. Herein, gold nanorods (Au NRs) with a length of about 40 nm (aspect ratio of 7:1) are successfully prepared by a seed‐mediated growth method. LiFePO 4 composite cathodes with 0.1/0.5/1 wt% Au NRs are compared with a pristine LiFePO 4 cathode, which shows that the addition of Au NRs can improve the electron and lithium‐ion transport. Specifically, the addition of 1 wt% Au NRs increases the electrical conductivity and lithium‐ion diffusion coefficient to 1.99 S cm −1 and 1.32 × 10 −14 cm 2 s −1 , respectively. The distribution of relaxation times analysis is carried out for the electrochemical impedance spectrum data to distinguish different electrochemical reactions within corresponding frequency regions. Particularly, LiFePO 4 with 0.1 wt% Au NRs exhibits a superior rate capability (133.7 mAh g −1 at 2C and 91.9 mAh g −1 at 5C) and stable cycling performance.