Flexible Freestanding MoO3−x–Carbon Nanotubes–Nanocellulose Paper Electrodes for Charge-Storage Applications

Abstract

Herein, a one-step synthesis protocol was developed for synthesizing freestanding/flexible paper electrodes composed of nanostructured molybdenum oxide (MoO3−x) embedded in a carbon nanotube (CNT) and Cladophora cellulose (CC) matrix. The preparation method involved sonication of the precursors, nanostructured MoO3−x, CNTs, and CC with weight ratios of 7:2:1, in a water/ethanol mixture, followed by vacuum filtration. The electrodes were straightforward to handle and possessed a thickness of approximately 12 μm and a mass loading of MoO3−x–CNTs of approximately 0.9 mg cm−2. The elemental mapping showed that the nanostructured MoO3−x was uniformly embedded inside the CNTs–CC matrix. The MoO3−x–CNTs–CC paper electrodes featured a capacity of 30 C g−1, normalized to the mass of MoO3−x–CNTs, at a current density of 78 A g−1 (corresponding to a rate of approximately 210 C based on the MoO3 content, assuming a theoretical capacity of 1339 C g−1), and exhibited a capacity retention of 91 % over 30 000 cycles. This study paves the way for the manufacturing of flexible/freestanding nanostructured MoO3−x-based electrodes for use in charge-storage devices at high charge/discharge rates.