Abstract:
Thanks to its high theoretical specific capacity (693 mAh/g), tungsten oxide (WO
3) is a good substitute for anode material of lithium-ion batteries. However, WO
3 suffers a large volume change during the process of lithium-ion removal/embedding, leading to the rapid decline of discharge specific capacity. Therefore, the cycle stability of WO
3 anode electrode has been one of the research focuses. H-WO
3/CMF and S-WO
3/CMF composite electrodes were successfully synthesized on CMF substrate by hydrothermal method and spraying method, respectively. XRD results show that WO
3 in H-WO
3/CMF and S-WO
3/CMF are categorized into monoclinic phase and hexagonal phase respectively. H-WO
3/CMF and S-WO
3/CMF were separately assembled into button cells for electrochemical performance test. The results show that the first discharge specific capacity of H-WO
3/CMF was higher than that of S-WO
3/CMF. When H-WO
3/CMF was cycled at a rate of 0.2 C, the specific discharge capacity reached 635 mAh/g in the first cycle and 510 mAh/g in the 50 cycles, which still showed an upward trend. When S-WO
3/CMF is cycled at 0.2 C, the specific discharge capacity in the first cycle is only 515 mAh/g, and the capacity decays rapidly in the subsequent cycle. Ac impedance test results show that the conductivity of H-WO
3/CMF is higher than that of S-WO
3/CMF. The research results show that H-WO
3/CMF, as the negative electrode of lithium-ion battery, is expected to improve the electrochemical stability of WO
3.