▎ 摘　　要

2D MXenes have been brought into sharp focus in electrochemical energy-storage devices due to their excellent electronic conductivity, high specific surface area, tunable layer structure, and large redox-active surface areas. Nevertheless, further applications of MXenes as electrode materials for supercapacitors are severely limited by the low theoretical specific capacity and self-restacking. Herein, a Ti3C2Tx @NiO heterostructure is constructed firstly by uniformly deposition of NiO nanosheets on Ti3C2Tx substrate, then the composite is incorporated into 3D porous hydrogel via an efficient graphene oxide (GO)-assisted self-convergence hydrothermal strategy with low temperatures. Owing to the synergistic effect among each components and the 3D porous interconnected architecture, the resultant 3D hierarchical Ti3C2Tx @NiO-Reduced Graphene Oxide (RGO) heterostructure hydrogel not only takes both merits of highly conductive and outstanding pseudocapacitive, but also significantly prevents the aggregation and increases the surface utilization of Ti3C2Tx @NiO. The 3D hierarchical Ti3C2Tx @NiO-RGO heterostructure hydrogel electrodes (without binders) exhibit an enhanced electrochemical performance, with a superb specific capacitance up to 966 F g(-1) at 1 A g(-1) and long-term stability of 94.5% over 10,000 cycles. Importantly, a maximum energy density of 58.5 Wh kg(-1) is obtained at power density of 550 W kg(-1). Our work provides a facile and efficient approach to develop Ti3C2Tx-based heterostructure hydrogels with improved overall performance, which expands the practical applications of MXenes in supercapacitors. (C) 2022 Elsevier B.V. All rights reserved.