导电氮化物改性氧化钨催化剂提升锂硫电池电化学性能

Conductive nitride-modified tungsten oxide catalyst improves electrochemical performance of lithium-sulfur batteries

摘要:

实验通过浮动催化CVD法在制备碳纳米管(CNTs)堆叠成膜过程中喷洒前驱体WCl6乙醇溶液,自然风干成膜,然后将膜水热并煅烧即可得到WO2.9-W2N/CNTs复合膜。W2N可改善WO3的导电性, WO2.9与WO3比较,其氧缺陷可为Li2S沉积提供更多活性位点,WO2.9-W2N还可与多硫化物(LiPSs)形成Li-O、Li-N键,使基体对LiPSs的化学吸附与锚定增强。以复合膜为正极的锂硫电池在0.2 C倍率下500次循环后,放电比容量依然保持大于850 mAh g-1,说明合成的WO2.9-W2N对电池电化学反应时的催化效果明显。

Abstract:

In this study, WO2.9-W2N can be obtained by spraying the precursor during the preparation of carbon nanotube films (CNTs), followed by hydrothermal treatment and calcination. The use of W2N can improve the poor conductivity of WO3. In addition, the oxygen vacancies can be caused by WO2.9 that provide more active sites for the deposition of Li2S, and form Li-O with polysulfides (LiPSs), Li-N bond. The results demonstrate the chemical adsorption and anchoringof LiPSs onto the matrix strengthened, and thereby the prepared battery indicates excellent electrochemical performances, after 500 cycles at a rate of 0.2 C, the discharge specific capacity remains 850 mAh g-1, showing excellent electrochemical reaction kinetics and its catalytic effect to the electrochemical reactions. Therefore, the shuttling inhibition of WO2.9-W2N/CNTs is mainly occurred by trapping-anchoring-catalytic conversion.