Abstract

Lithium–sulfur (Li–S) batteries have established a tremendous interest in recent years because of their high specific capacity (1675 mAh g⁻¹) and energy density (2600 Wh kg⁻¹). In the present work, the electrode comprising carbon source viz., Acetylene Black (AB) and Manganese Oxide (MnO₂) to serve as an efficient sulfur host in two different ratios (MnO₂:AB as 10:20 (M1) and 20:10 (M2)) for Li/dissolved polysulfide batteries. The composite was characterized and studied by X-ray diffraction (XRD), Raman Spectroscopy, Nitrogen adsorption/desorption measurements, High-resolution transmission electron microscopy (HRTEM), X-ray photon spectroscopy (XPS), Thermogravimetric analysis (TGA) and electrochemical performance such as cyclic voltammetry (CV) and charge–discharge (C/D) tests. It shows good cycle performance and exhibits an initial capacity of 1540 mAh/g at 0.1 C between 1.5 and 3.0 V for MnO₂ rich sample. Performance enhancement was also brought about by the adsorptive properties of MnO₂ which help in locking the polysulfide discharge products within the cathode structure.

Graphic Abstract

• The partial graphitic character of carbon allows electron transport.

• The strong adsorption behavior of MnO₂ prevents the dissolution of polysulfides.

• The above characteristics behavior of carbon and MnO₂ in the composite contributes to high rate performance and long cyclic stability.

  

中文翻译：

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嵌套有MnO 2 / AB复合材料混合物的硫可作为高性能Li–S电池的有效基质

摘要

锂硫（Li–S）电池由于其高的比容量（1675 mAh g ^-1）和能量密度（2600 Wh kg ^-1）而在近年来引起了极大的兴趣。在本工作中，电极包含碳源，即乙炔黑（AB）和氧化锰（MnO ₂），以两种不同的比例（MnO ₂：对于Li /溶解的多硫化物电池，AB为10:20（M1）和20:10（M2））。通过X射线衍射（XRD），拉曼光谱，氮吸附/解吸测量，高分辨率透射电子显微镜（HRTEM），X射线光子光谱（XPS），热重分析（TGA）和电化学对复合材料进行表征和研究性能，例如循环伏安法（CV）和充放电（C / D）测试。对于富MnO _2的样品，它显示出良好的循环性能，并且在0.1 C下1.5至3.0 V之间的初始容量为1540 mAh / g 。MnO ₂的吸附性能也带来了性能增强，这有助于将多硫化物放电产物锁定在阴极结构内。

图形摘要

• 碳的部分石墨特征允许电子传输。

• MnO ₂的强吸附行为阻止了多硫化物的溶解。

• 碳和MnO ₂在复合物中的上述特征行为有助于高速率性能和长循环稳定性。