Development of cerium and natural fibers freestanding composite electrodes for modern bendable energy storage applications

Flexible and environmentally safe electrodes are high in demand for modern energy storage devices. This study reports the fabrication of cerium oxide (CeO2) and cerium oxide-manganese oxide nanoparticles (Ce0.98 Mn0.02 O2 NPs) via co-precipitation synthesis technique and further development of bendable paper-based energy storage electrodes by employing lignocelluloses fibers as binder, extracted from self-growing plant, Monochoria Vaginalis. The structural and optical properties of the prepared products are carried out by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). XRD study reveals that Mn ions are incorporated into the CeO2 lattice to synthesize the Ce0.98 Mn0.02 O2 nanoparticles. SEM/EDX and TEM/SAED are performed for surface morphological analysis and successful composite formation of CeO2/LC and Ce0.98 Mn0.02O2/LC sheets. Electrochemical measurements of CeO2/LC and Ce0.98 Mn0.02O2/LC composite sheets were performed where fabricated sheets were employed as freestanding working electrode in 2 M KOH electrolyte. CeO2/LC and Ce0.98 Mn0.02O2/LC composite sheets have shown specific capacitances of 401.5 and 544 F/g, respectively from three electrode cyclic voltammetry (CV) measurements. 2-electrodes galvanostatic charge–discharge (GCD) measurements were performed in symmetric cell which reveal the capacitance of 436 F/g and 560 F/g for CeO2/LC and Ce0.98 Mn0.02O2/LC composite paper sheets, respectively. The Ce0.98 Mn0.02O2/LC (1:1) composite paper sheet shows the capacitance retention stability up to 80% after 1000 cycles at applied current density of 3.3 A/g. It can conclude that the fabricated paper electrodes can employ as working electrodes in modern energy storage devices having dual advantages of flexible and environmentally safe characteristics in the absence of any synthetic substrate/binder.