Electrophoretically deposited binder-free 3-D carbon/sulfur nanocomposite cathode for high-performance Li-S batteries

• 作者: Chi-Yuen Chung Hafiz Khurram Shahzad Jie Fang Robin Lok-Wang Ma Samson Ho-Sum Cheng Sasan Ghashghaie
• 来源期刊: 能源化学
• 年，卷（期）: 2020,（9）
• 页码范围: 92-101
• 页数: 10页
• 语种: 英文

摘要

In the present study,the electrophoretic deposition method was successfully applied as a binder-free and scalable approach to deposit carbonaceous nanomaterials on carbon fiber paper (CFP) for cathode applications in Li-S batteries.The microstructural studies of the EPD-CNT film using scanning electron microscopy (SEM) revealed the formation of a crack-free and porous layer of CNTs being uniformly distributed on the CFP surface.The EPD:CFP/CNT/S cathode delivered a capacity around 2.2 times higher than that obtained in the absence of the EPD-CNT film (CFP/S cell) after 50 cycles and a capacity of 935 mAh g-1 after 100 cycles at 0.1 C.The EPD method was then employed to fabricate layer-by-layer structures where the EPD-CNT film was decorated with carbon black particles.The initial capacity as well as the reversible capacity after 100 cycles was further increased by the EPD:CFP/CNT/KB/S layer-by-layer structure to 1473 and 1033 mAh g-1,respectively,indicating effective suppression of the shuttle effect.In addition,the rate performance of CFP/S was improved by depositing the EPD-CNT and EPD-CNT/carbon black architectures on CFP surface,and even further enhanced through the co-deposition of CNT and Pt nanoparticles by EPD,delivering a specific capacity of around 730 mAh g-1 at 1 C.Finally,the cathodes fabricated by EPD were observed to outperform those made by the conventional casting method in terms of cycling performance,internal resistance,and polarization.This difference was ascribed to the non-uniform microstructure of the Cast-CNT film,which resulted in poor interfacial connection between the CNT agglomerates,hindering uniform sulfide/sulfur deposition during cycling.The obtained results suggested that the binder-free C/S nanocomposite cathode made by EPD is key to further enhance the specific capacity and energy density of Li-S batteries.