Adhikari Pashupati R, Lee Eunji, Smith Lee, Kim Jeongyong, Shi Sheldon, Choi Wonbong
Department of Mechanical Engineering, University of North Texas 3940 North Elm St Denton TX 76207 USA
Department of Energy Science, Sungkyunkwan University Suwon 16419 Republic of Korea.
RSC Adv. 2023 Mar 22;13(14):9402-9412. doi: 10.1039/d3ra00502j. eCollection 2023 Mar 20.
Lithium-sulfur batteries (LSBs) demonstrate potential as next-generation energy storage systems due to the high theoretical capacity and energy density of the sulfur cathode (1672 mAh g and 2600 W h kg, respectively) in addition to the low-cost, natural abundance, and environmentally benign characteristics of sulfur. However, the insulating nature of sulfur requires an efficient conductive and porous host material such as three-dimensional carbon nanotubes (3D CNTs). Identifying parameters that provide high conduction pathways and short diffusion lengths for Li-ions within the CNT structure is essential for a highly efficient CNT-S cathode in a LSB. Herein, the effect of morphological variation in 3D CNTs as a sulfur host material is studied, and parameters that affect the performance of a CNT-S cathode in LSB are investigated. Four different 3D CNTs are synthesized the chemical vapor deposition (CVD) technique that vary in specific surface area (SSA), CNT diameter, pore sizes, and porosity. The superior 3D CNT-S (CNT-S-50) cathode, which possessed high surface area and porosity as compared to the rest of the 3D CNT-S cathodes, with ∼38 wt% (6.27 mg cm) sulfur loading, demonstrated an areal and specific discharge capacity of 8.70 mAh cm and 1387 mAh g at 0.1C, respectively. Results from this work demonstrate that the combination of high surface area and porosity are two crucial parameters in 3D CNTs as an efficient sulfur host material for LSB cathodes.
锂硫电池（LSB）因其硫阴极具有高理论容量和能量密度（分别为1672 mAh g和2600 W h kg），以及硫的低成本、天然丰度和环境友好特性，而展现出作为下一代储能系统的潜力。然而，硫的绝缘性质需要一种高效的导电且多孔的主体材料，如三维碳纳米管（3D CNT）。确定能为Li离子在CNT结构内提供高传导路径和短扩散长度的参数，对于LSB中高效的CNT-S阴极至关重要。在此，研究了作为硫主体材料的3D CNT形态变化的影响，并研究了影响LSB中CNT-S阴极性能的参数。采用化学气相沉积（CVD）技术合成了四种不同的3D CNT，它们在比表面积（SSA）、CNT直径、孔径和孔隙率方面有所不同。与其他3D CNT-S阴极相比，具有高表面积和孔隙率的优异3D CNT-S（CNT-S-50）阴极，硫负载量约为38 wt%（6.27 mg cm），在0.1C下的面积比放电容量和比放电容量分别为8.70 mAh cm和1387 mAh g。这项工作的结果表明，高表面积和孔隙率的结合是3D CNT作为LSB阴极高效硫主体材料的两个关键参数。
