Dharmasena Ruchira, Thapa Arjun Kumar, Hona Ram Krishna, Jasinski Jacek, Sunkara Mahendra K, Sumanasekera Gamini U
Conn Center for Renewable Energy Research, University of Louisville KY USA
Department of Physics & Astronomy, University of Louisville KY USA
RSC Adv. 2018 Mar 26;8(21):11622-11632. doi: 10.1039/c8ra01380b. eCollection 2018 Mar 21.
In this paper, a meso-porous TiO (titania) coating is shown to effectively protect a carbon-sulfur composite cathode from polysulfide dissolution. The cathode consisted of a sulfur impregnated carbon support coated with a few microns thick mesoporous titania layer. The carbon-sulfur cathode is made using activated carbon powder (ACP) derived from biomass. The mesoporous titania coated carbon-sulfur cathodes exhibit a retention capacity after 100 cycles at C/3 rate (433 mA g ) and stabilized at a capacity around 980 mA h g. The electrochemical impedance spectroscopy (EIS) of the sulfur cathodes suggests that the charge transfer resistance at the anode, ( ) is stable for the titania coated sulfur electrode in comparison to a continuous increase in for the uncoated electrode implying mitigation of polysulfide shuttling for the protected cathode. Stability in the cyclic voltammetry (CV) data for the first 5 cycles further confirms the polysulfide containment in the titania coated cathode while the uncoated sulfur electrode shows significant irreversibility in the CV with considerable shifting of the voltage peak positions. Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) studies confirm the adsorption of soluble polysulfides by mesoporous titania.
在本文中，一种中孔二氧化钛（TiO）涂层被证明能有效保护碳硫复合阴极免受多硫化物溶解的影响。阴极由浸渍硫的碳载体组成，该载体涂覆有几微米厚的中孔二氧化钛层。碳硫阴极是使用源自生物质的活性炭粉末（ACP）制成的。中孔二氧化钛涂覆的碳硫阴极在C/3速率（433 mA g）下经过100次循环后表现出保留容量，并稳定在约980 mA h g的容量。硫阴极的电化学阻抗谱（EIS）表明，与未涂覆电极的持续增加相比，涂覆二氧化钛的硫电极在阳极处的电荷转移电阻（ ）是稳定的，这意味着受保护阴极的多硫化物穿梭得到缓解。前5个循环的循环伏安法（CV）数据中的稳定性进一步证实了涂覆二氧化钛的阴极中多硫化物的抑制，而未涂覆的硫电极在CV中显示出明显的不可逆性，电压峰值位置有相当大的偏移。拉曼光谱和X射线光电子能谱（XPS）研究证实了中孔二氧化钛对可溶性多硫化物的吸附。
