Flexible Freestanding MoO_3-x -Carbon Nanotubes-Nanocellulose Paper Electrodes for Charge-Storage Applications

Herein, a one-step synthesis protocol was developed for synthesizing freestanding/flexible paper electrodes composed of nanostructured molybdenum oxide (MoO_3-x ) embedded in a carbon nanotube (CNT) and Cladophora cellulose (CC) matrix. The preparation method involved sonication of the precursors, nanostructured MoO_3-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 MoO_3-x -CNTs of approximately 0.9 mg cm^-2 . The elemental mapping showed that the nanostructured MoO_3-x was uniformly embedded inside the CNTs-CC matrix. The MoO_3-x -CNTs-CC paper electrodes featured a capacity of 30 C g^-1 , normalized to the mass of MoO_3-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 MoO_3-x -based electrodes for use in charge-storage devices at high charge/discharge rates.