Intrinsic Charge Storage Capability of Transition Metal Dichalcogenides as Pseudocapacitor Electrodes

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• 作者：Xin Cong ; Chuan Cheng ; Yiming Liao ; Yifei Ye ; Changxu Dong ; He Sun ; Xiao Ji ; Wenqiang Zhang ; Peilin Fang ; Ling Miao ; Jianjun Jiang
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：September 10, 2015
• 年：2015
• 卷：119
• 期：36
• 页码：20864-20870
• 全文大小：468K
• ISSN：1932-7455

文摘

The intrinsic charge storage capability of a series of transition metal dichalcogenides (TMDs) (MS₂, M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zr, Nb, Mo, Tc, Hf, Ta, W, Re, and MoX₂, X = S, Se, Te) is investigated using density functional theory calculations. A map for pseudocapacitor electrodes is provided, depending on the demands of high conductivity and a remarkable peak of density of states (DOS) in the range of the electrolyte window. The calculated DOS suggests that most of the T phase structures are superior to H phase in electroconductibility. The charge storage capability is represented by the number of gaining or losing electrons calculated by integrating DOS in the electrolyte window. MS₂ (M = Ti, V, Cr, Fe, Nb, Mo, Tc) of the T phase is conductive and gains electrons easily with considerable valence state change of the TM atom, showing a redox pseudocapacitance character as a cathode. Meanwhile, CoS₂鈥揌 and MoSe₂鈥揟 are promising anode materials. Moreover, the chalcogen (S, Se, Te) with different electronegativity and work function will result in the changes of Fermi level and surface polarization of MoX₂, leading to the shift of their DOS in the electrolyte window. In another way, the metallic hydrogenated H phase of MoS₂ (MoS₂H₂) with conductivity should have enhanced advanced electrochemical performance.