Cellulose nanofiber/MXene (Ti3C2Tx)/liquid metal film as a highly performance and flexible electrode material for supercapacitors.

In recent times, there has been significant interest in the utilization of cellulose nanofiber (CNF) films as the foundation for supercapacitors due to their three-dimensional structure, flexibility and eco-friendliness. An ultrasonic and vacuum filtration method was used to prepare a hybrid film consisting of MXene (Ti3C2Tx), CNF and liquid metal (LM). The combination of CNF and LM with MXene produces a porous structure with higher electrical conductivity, which facilitates the transportation of ions and electrons within the composition and confers the material with heightened electrochemical properties. The CNF/MXene/LM electrode has a significant area capacitance of 871.3 mF cm-2 at a current density of 5 mA cm-2. The hybrid film demonstrates excellent stability, maintaining a high conductivity of 546.4 S∙cm-1 and retaining 96.9 % capacitance after 2000 cycles at a current density of 10 mA cm-2. By utilizing the thin film as an electrode, a high-performance quasi-solid supercapacitor was fabricated, with a remarkably thin thickness of only 0.319 mm. Supercapacitors show exceptional electrical properties, including a surface-specific capacitance of 188.2 mF cm-2 at a current density of 5 mA cm-2. This study indicates that flexible electrodes made from cellulose nanofiber have extensive potential in the realm of supercapacitors.

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

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.