Heterogeneous Ni-MOF/V2CTx–MXene hierarchically-porous nanorods for robust and high energy density hybrid supercapacitors

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2022-06, Vol.10 (22), p.12225-12234
• Main Authors: Yang, Xifeng, Tian, Yuhui, Li, Shuang, Ya-Pan, Wu, Zhang, Qichun, Dong-Sheng, Li, Zhang, Shanqing
• Format: Article
• Language: English
• Subjects: Activated carbon; Bonding strength; Chemical bonds; Electrode materials; Electrodes; Electronic structure; Heterogeneous structure; Interfaces; Metal foams; Metal-organic frameworks; Morphology; MXenes; Nanorods; Robustness; Specific capacity; Supercapacitors
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d2ta02114e

Interfacial engineering is an appealing strategy to construct heterogeneous nanostructures and tunes the morphology of metal–organic frameworks (MOFs) and MXenes for hybrid supercapacitors. Herein, a temperature-controlled annealing process is introduced to fabricate Ni-MOFs/V2CTx–MXene (Tx denotes the surface groups, –O, –OH, and –F) composites on Ni foam (NF) (namely MOF/MXene/NF) and subsequently build the heterogeneous structure of a hierarchically-porous nanorod composite without a change in the crystalline structure. Experimental characterizations and theoretical calculations reveal that Ni–O–V bridging bonds are constructed at the Ni-MOF and V2CTx interfaces, which could be used to establish a favorable electronic structure in promoting conductivity and reactivity. The optimized MOF/MXene/NF electrode obtained at 300 °C (i.e., MOF/MXene/NF-300) delivers an ultrahigh specific capacity of 1103.9 C g−1 at 1 A g−1. The as-assembled hybrid supercapacitor, composed of MOF/MXene/NF-300 as the cathode and activated carbon/NF as the anode, delivers a high energy density of 46.3 W h kg−1 at a power density of 746.8 W kg−1 and an outstanding cycling stability of ca. 118.1% capacity retention after 15 000 cycles. Such an achievement stems from the strong chemical bonds at the interface and unique porous morphology. This work suggests a new avenue for designing and preparing robust and high-performance electrode materials for hybrid supercapacitors.