An Investigation Of The Energy Storage Properties Of A 2d Alpha-Moo3-Swcnts Composite Films

We recently reported on the synthesis of 2D alpha-MoO3 using a scalable liquid-phase exfoliation method, its characterization and preliminary studies of its potential for energy storage applications [1]. The material was examined in a LiClO4/propylene carbonate electrolyte, and in a 1.5-3.5Vversus Li+/Li electrochemical window [1]. The charge storage of 2D alpha-MoO3 electrodes was negligible and this was attributed to electrical limitations imposed by the semiconducting nature of 2D alpha-MoO3. Electrical conductivity studies of 2D alpha-MoO3/SWCNT electrodes, where a fraction of SWCNTs was progressively added, led to finding the SWCNT fraction for which an electrical percolation threshold was reached, i.e.a sharp increase of electrical conductivity. This SWCNT fraction also led to a sharp increase in capacitance confirming the electrical limitation of charge storage. In this work, we examined in detail the energy storage properties of 2D alpha-MoO3/SWCNT( 85 wt%/15 wt%) electrodes. A detailed study of ion-intercalation events, as examined by cyclic voltammetry, is presented. We investigated the contributions to the overall energy storage of capacitive and diffusion-controlled processes and how the performance compares against other nanostructured materials including mesoporous alpha-MoO3 and alpha-MoO3 nanobelts. Our main findings showed that 2D alpha-MoO3/SWCNT( 85 wt%/15 wt%) electrodes offer scope for supercapacitors and battery applications in terms of total charge storage (200 F g(-1) and 195.2 mAh g(-1)), which is in the range or superior to that of other nanostructured metal oxides and commercial LiCoO2 cathodes. However, a main drawback is cycling stability.