High‐Rate and Long‐Life Au Nanorods/LiFePO₄ Composite Cathode for Lithium‐Ion Batteries

Abstract

LiFePO4 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. LiFePO4 composite cathodes with 0.1/0.5/1 wt% Au NRs are compared with a pristine LiFePO4 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 cm2 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, LiFePO4 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.

A Zero-Strain Insertion Cathode Material for Room-Temperature Fluoride-Ion Batteries

“…The battery was tested at 10 mA g –1 with an interval of 10 min and placed for 1 h for potential equilibrium. This process is recurrent from 2.2 to 3.9 V. As shown in Figure b, the calculated F – diffusion coefficients, in the order of 10 –12 –10 –14 cm 2 s –1 in both the charge and discharge of CoFe-F LDH, are comparable to the diffusion coefficients of the other FIB cathode materials at high temperatures reported so far and some LIB cathode materials at room temperature. − The weak interaction between the fluoride ions and host layers of CoFe-F LDH endows high ion diffusion coefficients, resulting in facile electrochemical energy storage.…”