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

Abstract

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 (Ti₃C₂T_x), 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.

Keywords: Cellulose nanofiber; Liquid metal; Supercapacitor.