Two-dimensional vanadyl phosphate ultrathin nanosheets for high energy density and flexible pseudocapacitors

• Published in: Nature communications Vol. 4; no. 1; p. 2431
• Main Authors: Wu, Changzheng, Lu, Xiuli, Peng, Lele, Xu, Kun, Peng, Xu, Huang, Jianliu, Yu, Guihua, Xie, Yi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 12.09.2013; Nature Publishing Group
• Subjects: 639/301/119/995; 639/638/161; 639/925/927; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms3431

Two-dimensional materials have been an ideal material platform for constructing flexible ultrathin-film supercapacitors, offering great advantages of flexibility, ultra-thinness and even transparency. Exploring new two-dimensional pseudocapacitive materials with high electrochemical activity is needed to achieve flexible ultrathin-film supercapacitors with higher energy densities. Here we report an inorganic graphene analogue, α 1 -vanadyl phosphate ultrathin nanosheets with less than six atomic layers, as a promising material to construct a flexible ultrathin-film pseudocapacitor in all-solid-state. The material exhibits a high potential plateau of ~ 1.0 V in aqueous solutions, approaching the electrochemical potential window of water (1.23 V). The as-established flexible supercapacitor achieves a high redox potential (1.0 V) and a high areal capacitance of 8,360.5 μF cm −2 , leading to a high energy density of 1.7 mWh cm −2 and a power density of 5.2 mW cm −2 . Graphene-like materials with pseudocapacitive characteristics are desirable for flexible solid-state pseudocapacitors. Here Wu et al . report such a graphene analogue, vanadyl phosphate ultrathin nanosheets, which exhibits excellent pseudocapacitive properties, leading to a high energy density.