Molybdenum–Tungsten Mixed Oxide Deposited into Titanium Dioxide Nanotube Arrays for Ultrahigh Rate Supercapacitors

Abstract

A novel method involving the fabrication of Mo-W mixed oxide (MoWO) is proposed to modify the modest reaction kinetics and poor cycling stability of MoO material. By a simple coelectrodeposition method, a series of MoWO oxides is deposited on a TiO nanotube array substrate. Because of the differences between Mo and W in nature, there is significant distortion existing in the mixed oxides, leading to their decreased crystallite size and enlarged lattice space, which facilitates ion diffusion in the solid. As results, the mixed oxides show much better balance between specific capacitance and cycling stability than the bare MoO or WO sample, which suffers from either poor cycling stability or low electrochemical activity. Impressively, the optimal Mo-W mixed oxide exhibits a high specific capacitance of 517.4 F g at 1 A g, and, moreover, it retains 89.3% of the capacitance even at a high current density of 10 A g, demonstrating ultrahigh rate capability. These findings reveal the potential of the Mo-W mixed oxide for constructing advanced ultrahigh power supercapacitors.

Review on Recent Progress in the Development of Tungsten Oxide Based Electrodes for Electrochemical Energy Storage

“…Zhou et al. demonstrated the synthesis of Mo x W 1− x O 3 on TiO 2 nanotube arrays through a coprecipitation method . The resultant mixed oxide composite electrode exhibited a specific capacitance of 517.4 F g −1 at 1 A g −1 , and 89.3 % of the initial capacitance at a current density of 10 A g −1 .…”

“…Zhou et al demonstrated the synthesis of Mo x W 1Àx O 3 on TiO 2 nanotube arrays throughacoprecipitation method. [112] The resultant mixed oxide composite electrode exhibitedaspecific capacitance of 517.4 Fg À1 at 1Ag À1 ,a nd 89.3 %o ft he initial capacitance at ac urrent density of 10 Ag À1 .Y uan et al developed ab inder-free nano-WO 3 ·H 2 O-MnO 2 (NWMO) composite electrode througha na nodic deposition method for SCs. [113] The prepared NWMO electrode exhibited ah igh specific capacitance of 363 Fg À1 at 0.5 Ag À1 ,ag ood rate capability (210.3 Fg À1 at 10 Ag À1 ), and ac apacitance retention of 93.8 % over 5000 cycles.…”

Hydrothermal syntheses of tungsten doped TiO2 and TiO2/WO3 composite using metal oxide precursors for charge storage applications

“…There have been many reports on the energy storage properties of both TiO 2 and WO 3 as electrodes for lithium ion batteries [14,15] and supercapacitors [16,17]. Among various pseudosupercapacitor materials, TiO 2 has received exceptional interest because of their low cost, excellent chemical stability, abundance and low environmental impact [18].…”

Review on Nanoarchitectured Current Collectors for Pseudocapacitors

“…Beyond that, Mirvakili and Hunter took a similar etching approach combining with bundle‐drawing procedure and successfully fabricated vertically aligned niobium nanowire arrays, which displayed an ultrafast‐charging performance with a remarkable power density. Likewise, anodic oxidation of Ti substrate is also a conventional top‐down strategy for fabrication of TiO 2 nanotube arrays . Due to the highly oriented structure with large surface area, TiO 2 nanotube arrays served as an attractive scaffold for pseudocapacitive nanomaterials.…”