氧化钨/碳纳米管膜复合负极的制备及其储锂性能

氧化钨(WO₃)因具有较高的理论比容量(693 mAh/g)已成为锂离子电池负极材料的有力候选者。但在电池充放电即锂离子脱/嵌入过程中WO₃会产生较大的体积变化，导致其放电比容量快速衰减，故对其循环稳定性研究仍是热点之一。文中采用水热法和喷涂法分别在碳纳米管膜(CMF)基底上成功合成了水热型-氧化钨/碳纳米管膜(H-WO₃/CMF)和喷涂型-氧化钨/碳纳米管膜(S-WO₃/CMF)复合电极。XRD测试结果显示H-WO₃/CMF和S-WO₃/CMF中的WO₃分别属于单斜相和六方相。将H-WO₃/CMF和S-WO₃/CMF分别组装成扣式电池进行电化学性能测试，结果表明H-WO₃/CMF的首次放电比容量高于S-WO₃/CMF。当H-WO₃/CMF以0.2 C倍率循环时，第1圈放电比容量达到635 mAh/g，循环50圈时放电比容量为510 mAh/g，仍有上升趋势; S-WO₃/CMF在0.2 C倍率下循环时，第1圈放电比容量仅为515 mAh/g，在后续循环过程中容量衰减较快。交流阻抗测试结果显示H-WO₃/CMF的导电性高于S-WO₃/CMF。研究结果表明:H-WO₃/CMF作为锂离子电池负极，有望提升WO₃的电化学稳定性。 

Preparation of Tungsten oxide/carbon nanotube film composite anodes and their lithium storage performance

Thanks to its high theoretical specific capacity (693 mAh/g), tungsten oxide (WO₃) is a good substitute for anode material of lithium-ion batteries. However, WO₃ 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 WO₃ anode electrode has been one of the research focuses. H-WO₃/CMF and S-WO₃/CMF composite electrodes were successfully synthesized on CMF substrate by hydrothermal method and spraying method, respectively. XRD results show that WO₃ in H-WO₃/CMF and S-WO₃/CMF are categorized into monoclinic phase and hexagonal phase respectively. H-WO₃/CMF and S-WO₃/CMF were separately assembled into button cells for electrochemical performance test. The results show that the first discharge specific capacity of H-WO₃/CMF was higher than that of S-WO₃/CMF. When H-WO₃/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-WO₃/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-WO₃/CMF is higher than that of S-WO₃/CMF. The research results show that H-WO₃/CMF, as the negative electrode of lithium-ion battery, is expected to improve the electrochemical stability of WO₃.