Zhang Qiang, Gao Ruijie, Li Zixiong, Zhou Binghui, Tang Aidong, Wang Jian, Zou Ji-Jun, Yang Huaming
Hunan Key Lab of Mineral Materials and Application, School of Minerals Processing and Bioengineering, Central South University, Changsha, 410083, China.
Engineering Research Center of Nano-Geomaterials of Ministry of Education, China University of Geosciences, Wuhan, 430074, China.
Small. 2022 Feb;18(6):e2105661. doi: 10.1002/smll.202105661. Epub 2021 Dec 2.
Polar oxides are widely used as the cathodes to impede the shuttle effect in lithium-sulfur batteries, but suffer from the sluggish desorption and conversion of polysulfides due to too strong affinity of polysulfides on oxygen sites. Herein, employing halloysite as a model, an approach to overcome these shortcomings is proposed via engineering oxygen p-band center by loading titanium dioxide nanoparticles onto Si-O surface of halloysite. Using density functional theory calculations, it is predicted that electron transfer from titanium dioxide nanoparticles to interfacial O sites results in downshift of p-band center of O sites that promote desorption of polysulfides and the cleavage of Li-S and S-S, accelerating the conversion kinetics of polysulfides. The designed composite cathode material delivers outstanding electrochemical performance in Li-S batteries, outperforming the recently reported similar cathodes. The concept could provide valuable insight into the design of other catalysts for Li-S batteries and beyond.
极性氧化物被广泛用作锂硫电池中的阴极，以抑制穿梭效应，但由于多硫化物对氧位点的亲和力过强，导致多硫化物的解吸和转化缓慢。在此，以埃洛石为模型，提出了一种通过将二氧化钛纳米颗粒负载到埃洛石的Si-O表面来调控氧p带中心，从而克服这些缺点的方法。利用密度泛函理论计算预测，二氧化钛纳米颗粒向界面O位点的电子转移导致O位点的p带中心下移，促进多硫化物的解吸以及Li-S和S-S键的断裂，加速多硫化物的转化动力学。所设计的复合阴极材料在锂硫电池中表现出优异的电化学性能，优于最近报道的类似阴极材料。这一概念可为锂硫电池及其他领域的其他催化剂设计提供有价值的见解。
