Nulu Arunakumari, Nulu Venugopal, Sohn Keun Yong
Department of Nanoscience and Engineering, Center for Nano Manufacturing, Inje University 197 Inje-ro Gimhae Gyeongnam-do 50834 Republic of Korea
RSC Adv. 2024 Jan 15;14(4):2564-2576. doi: 10.1039/d3ra08507d. eCollection 2024 Jan 10.
Lithium-sulfur (Li-S) batteries are considered promising next-generation energy storage devices due to their low cost and high energy density (2600 W h kg). However, the practical applicability of Li-S batteries is hindered by the insulating nature of sulfur cathodes, and the high solubility of polysulfides (LiS, 3 < ≤ 8) which are formed during the electrochemical process. Integrating sulfur into the carbon host is an effective way to enhance the conductivity of the electrode which hampers the shuttling effect of the polysulfides. Here in this study, hierarchical porous carbon structures (HPC) are prepared from spent coffee waste (SCW) by the KOH activation process and are encapsulated with sulfur (SHPC) which increases the interaction between sulfur and carbon and enhances both the electronic and ionic conductivities. Further wrapping of SHPC with N-doped multi-walled carbon nanotubes (NCNTs) gives a SHPC-NCNT composite, which alleviates the shuttling of polysulfides by trapping them and ensures the required conductivity to the sulfur cathode during the Li reactions. When studied as a cathode material for Li-S batteries, the prepared cathode showed 664 and 532 mA h g specific capacities after 150 cycles at 0.2C and 0.5C, respectively. The stable cyclability and rate capability properties of SPHCNCNT suggest that the prepared sulfur composite is suitable as a cathode material for Li energy storage applications.
锂硫（Li-S）电池因其低成本和高能量密度（2600 W h kg）而被认为是很有前景的下一代储能设备。然而，硫阴极的绝缘性质以及电化学过程中形成的多硫化物（LiS，3 < ≤ 8）的高溶解度阻碍了Li-S电池的实际应用。将硫整合到碳主体中是提高电极导电性的有效方法，这有助于抑制多硫化物的穿梭效应。在本研究中，通过KOH活化工艺由废弃咖啡渣（SCW）制备了分级多孔碳结构（HPC），并将硫封装在其中（SHPC），这增加了硫与碳之间的相互作用，提高了电子和离子导电性。用氮掺杂的多壁碳纳米管（NCNTs）进一步包裹SHPC得到SHPC-NCNT复合材料，该复合材料通过捕获多硫化物减轻了多硫化物的穿梭，并在锂反应过程中确保了硫阴极所需的导电性。当作为Li-S电池的阴极材料进行研究时，制备的阴极在0.2C和0.5C下循环150次后，比容量分别为664和532 mA h g。SPHCNCNT的稳定循环性能和倍率性能表明，制备的硫复合材料适合作为锂储能应用的阴极材料。
