MXene (Ti3C2Tx)/cellulose nanofiber/polyaniline film as a highly conductive and flexible electrode material for supercapacitors.

ABSTRACT

In recent years, supercapacitors based on cellulose nanofiber (CNF) films have received considerable attention for their excellent flexibility, lightweight, and unique structure. In this study, MXene (Ti3C2Tx) /CNF/polyaniline (PANI) hybrid films with good conductivity and flexibility were prepared by a convenient vacuum filtration method. Combined with PANI, MXene creates an open structure with high conductivity, which facilitates ion and electron transport among the materials and provides the composite with high electrochemical activity. The MXene/CNF/PANI electrode presents a high areal specific capacitance of 2935 mF cm-2 at the current density of 1 mA cm-2, excellent cycling stability with high capacitance retention of 94 % after 2000 cycles at 10 mA cm-2 and high electrical conductivity (634.4 S∙cm-1). As a further application of this film, it is used as a free-standing electrode to fabricate a quasi-solid-state supercapacitor with high performance, which has an ultra-thin thickness of 0.344 mm, a significantly high areal specific capacitance (522 mF cm-2) at 5 mA cm-2, a high areal energy density of 94.7 µWh∙cm-2 and a high areal power density of 573 µW∙cm-2. This work shows the great potential of the developed high-performance and flexible cellulose-based composites for fabricating electrodes as well as supercapacitors.