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A New Facile Synthesis of Tungsten Oxide from Tungsten Disulfide: Structure Dependent Supercapacitor and Negative Differential Resistance Properties
Author(s) -
Mandal Debasish,
Routh Parimal,
Nandi Arun K.
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201702881
Subject(s) - supercapacitor , materials science , orthorhombic crystal system , tungsten disulfide , graphene , electrode , tungsten , oxide , chemical engineering , electrochemistry , nanotechnology , power density , crystallography , crystal structure , chemistry , composite material , metallurgy , power (physics) , physics , quantum mechanics , engineering
Tungsten oxide (WO 3 ) is an emerging 2D nanomaterial possessing unique physicochemical properties extending a wide spectrum of novel applications which are limited due to lack of efficient synthesis of high‐quality WO 3 . Here, a facile new synthetic method of forming WO 3 from tungsten sulfide, WS 2 is reported. Spectroscopic, microscopic, and X‐ray studies indicate formation of flower like aggregated nanosized WO 3 plates of highly crystalline cubic phase via intermediate orthorhombic tungstite, WO 3. H 2 O phase. The charge storage ability of WO 3 is extremely high (508 F g −1 at current density of 1 A g −1 ) at negative potential range compared to tungstite (194 F g −1 at 1 A g −1 ). Moreover, high (97%) capacity retention after 1000 cycles and capacitive charge storage nature of WO 3 electrode suggest its supremacy as a negative electrode of supercapacitors. The asymmetric supercapacitor, based on the WO 3 as a negative electrode and mildly reduced graphene oxide as a positive electrode, manifests high energy density of 218.3 mWhm −2 at power density 1750 mWm −2 , and exceptionally high power density, 17 500 mW m −2 , with energy density of 121.5 mWh m −2 . Furthermore, the negative differential resistance (NDR) property of both WO 3 and WO 3 .H 2 O are reported for the first time and NDR is explained with density of state approach.