Electrodes and hydrogel electrolytes based on cellulose: fabrication and characterization as EDLC components

Abstract

In the present work, the cellulose-based materials were manufactured and used as components of electrochemical double layer capacitors (EDLCs). The preparation method of cellulose membranes as well as composite electrodes containing cellulose as a binder was presented. These materials were prepared using for the first time ionic liquid/dimethyl sulfoxide (IL/DMSO) mixture solvent. Obtained components displayed a uniform structure, thermal stability, and good electrochemical properties. The electrochemical performances of these materials were studied in 2-electrode EDLC cells by common electrochemical techniques as cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). The composite electrodes were investigated in three types of electrolytes: aqueous, organic, and ionic liquids. The cellulose membranes were, however, soaked in an aqueous electrolyte and tested as hydrogel polymer electrolytes. All investigated materials show high efficiency in terms of specific capacity. The studied cellulose-based capacitors exhibited specific capacitance values in the range of 20–22 F g−1, depending on the type of applied electrolyte.