3D Hierarchical Ti₃C₂T_X@PANI-Reduced Graphene Oxide Heterostructure Hydrogel Anode and Defective Reduced Graphene Oxide Hydrogel Cathode for High-Performance Zinc Ion Capacitors

Abstract

The practical application of supercapacitors (SCs) has been known to be restricted by low energy density, and zinc ion capacitors (ZICs) with a capacitive cathode and a battery-type anode have emerged as a unique technology that can effectively mitigate the issue. To this end, the design of electrodes with low electrochemical impedance, high specific capacitance, and outstanding reaction stability represents a critical first step. Herein, we report the synthesis of hierarchical Ti3C2T X @PANI heterostructures by uniform deposition of conductive polyaniline (PANI) polymer nanofibers on the exposed surface of the Ti3C2T X nanosheets, which are then assembled into a three-dimensional (3D) cross-linking framework by a graphene oxide (GO)-assisted self-convergence hydrothermal strategy. This resulting 3D Ti3C2T X @PANI-reduced graphene oxide (Ti3C2T X @PANI-RGO) heterostructure hydrogel shows a large surface area (488.75 F g–1 at 0.5 A g–1), outstanding electrical conductivity, and fast reaction kinetics, making it a promising electrode material. Separately, defective RGO (DRGO) hydrogels are prepared by a patterning process, and they exhibit a broad and uniform distribution of mesopores, which is conducive to ion transport with an excellent specific capacitance (223.52 F g–1 at 0.5 A g–1). A ZIC is subsequently constructed by utilizing Ti3C2T X @PANI-RGO as the anode and DRGO as the cathode, which displays an extensive operating voltage (0–3.0 V), prominent energy density (1060.96 Wh kg–1 at 761.32 W kg–1, 439.87 Wh kg–1 at 9786.86 W kg–1), and durable cycle stability (retaining 67.9% of the original capacitance after 4000 cycles at 6 A g–1). This study underscores the immense prospect of the Ti3C2T X -based heterostructure hydrogel and DRGO as a feasible anode and cathode for ZICs, respectively.

1,2,4,5-Benzene Tetracarboxylic Acid-Doped Polyaniline/Protonated Carbon Nitride Nanostructures for Cr(VI) Adsorption in Water

“…Notwithstanding these findings, conjugated PANI faces a few inconveniences, like limited mechanical and thermal resilience along with minute particle dimensions, which can restrict its applicability . To deal with the shortcomings of PANI, there have been some new advances in PANI-based composites with a variety of materials, such as PANI-ZrWPO 4 , Pt/CNT@PANI, PANI/zeolite HY/TiO 2 , cellulose/phytic acid/polyaniline hydrogel, UiO-66/PANI, hierarchical Ti 3 C 2 TX@PANI, PANI/SnO 2 , etc.…”