A facile, cost-effective synthesis of a Ti3C2T x (MXene) based polyindole nanocomposite has been explored in detail as both, a cathode and anode, for the fabrication of symmetric and asymmetric supercapacitor devices. The morphological analysis confirmed successful intercalation as well as coating of polyindole on MXene nanosheets. The concentration of polyindole was optimized with respect to MXene for optimum electrochemical performance. Surface area analysis confirmed the highest specific surface area for the MXene-Polyindole composite system with a 3:1 ratio of MXene and polyindole. The high specific capacitance of 226.5 F g–1, at 2 A g–1, current density and excellent cyclic stability of 90.5% after 8000 cycles were achieved for this nanocomposite. The designed asymmetric device with this composite as an anode achieved maximum specific capacitance of 117 F g–1 and energy density of 65.3 Wh kg–1. Most importantly, the MXene based composite displayed excellent electrochemical performance as both an anode and cathode in an asymmetric supercapacitor device. Moreover, the device was used to light up LEDs of different colors and power up a mini fan. With these electrochemical properties, this MXene-based hybrid composite can be considered as a potential candidate for next-generation supercapacitor devices.

Nanocellulose fiber-based composites have been studied as supercapacitor electrodes due to their mechanical and chemical stability. The non-conductivity of nanocellulose has been tuned by MXene, a 2D nanomaterial, and its composites, for use as electrode materials for energy storage applications. This work reports the synthesis of polyindole-stabilized nanocellulose-wrapped MXene nanocomposite-based electrodes for supercapacitors. Nanocellulose, extracted from various renewable biowastes, is wrapped around MXene nanosheets to prevent the restacking of Ti3C2T x layers with the structure being stabilized with polyindole. The morphology, structure, and chemical composition were confirmed with field-emission scanning electron microscopy (FESEM), X-ray diffraction, and X-ray photoelectron spectroscopy, respectively. Morphological analysis, by FESEM and transmission electron microscopy, confirmed successful synthesis of the ternary nanocomposites. The concentration of Ti3C2T x and nanocellulose was optimized to get best possible electrochemical performance of the electrodes. The best electrochemical performance was achieved with an MXene-grass cellulose-polyindole-1:1 composite [MPC(G)-1:1] with a specific capacitance of 858 F g–1 at 1 A g–1, in a three-electrode setup. An asymmetric device fabricated with developed nanocomposites as the cathode delivered a specific capacitance of 90 F g–1 and an energy density of 40.5 W h kg–1 at 1 A g–1 with 94.1% capacitance retention after 10,000 cycles. This study established the conversion of biowaste to efficient supercapacitor electrodes via a facile low-cost process.

A new class of two-dimensional (2D) materials known as MXene became one of the most promising candidates under investigation after the discovery of the first member of this group, Ti3C2Tx,...

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