【Research Background】

As a typical 2D MXene, Ti3C2Tx has been widely used as a super capacitor and battery material due to its good hydrophilic surface, high chemical stability, adjustable interlayer spacing, and high electrical conductivity. . However, the low specific capacitance of Ti3C2 MXene limits its applications. Therefore, some researches have been done to improve its specific capacitance. For a heterostructure based on Ti3C2, a battery-type material can be assembled with Ti3C2. 2D / 2D heterostructures can combine the advantages of different 2D materials and can even show improved performance through synergistic effects. 2D transition metal carbides Ti3C2 MXene and 2D 1T-MoS2 have become potential materials in the field of electrochemistry due to their respective characteristics. However, due to the instability of 1T-MoS2, there is a lack of research on the synergistic effect of the composite 2D materials.

[Achievement Profile]
Recently, Professor Xuebin Zhu and Professor Yuping Sun of the Chinese Academy of Sciences have published a research paper titled: 2D / 2D 1T-MoS2 / Ti3C2 MXene Heterostructure with Excellent Supercapacitor Performance in the internationally renowned academic journal Advanced Functional Materials. The study was successfully prepared. It has a three-dimensional interconnected network 1T-MoS2 / Ti3C2MXene heterostructure, and its electrochemical storage mechanism has been studied. Due to the synergy effect in the 3D interconnect network, the ionic storage space is enlarged, with additional capacitance contributions. At the same time, due to the ultra-fast electron transmission of Ti3C2MXene, it exhibits excellent rate performance. This work provides a prototype for achieving the excellent electrochemical performance of 2D / 2D heterostructures.

[Picture and text guide]
Figure 1. Schematic diagram of the synthesis of 3D heterostructures of 1T-MoS2 / Ti3C2MXene and 2H-MoS2 / Ti3C2 MXene, as well as the crystal structure and d-spacing of 2H-MoS2 and 1T-MoS2
Figure 2. Phase and crystal structure of the sample
Figure 3.2 Morphology of H-MoS2 / Ti3C2 MXene and 1T-MoS2 / Ti3C2 MXene heterostructures
Figure 4. Electrochemical performance of 2H-MoS2, 1T-MoS2, Ti3C2MXene, 2H-MoS2 / Ti3C2 MXene, 1T-MoS2 / Ti3C2 MXene electrodes
Figure 5.1 Energy storage mechanism of T-MoS2 / Ti3C2 MXene electrode
Figure 6. Electrochemical performance of flexible devices

[Summary of this article]
In this paper, XRD, Raman spectroscopy, SEM, TEM, and HRTEM correlation characterization confirm that the 1T-MoS2 / Ti3C2 MXene heterostructure with 3D interconnect network microstructure was successfully prepared by magnetic hydrothermal synthesis. Compared with 1T-MoS2 (357.4 F g-1) and Ti3C2 MXene (27.2 F g-1), the 1T-MoS2 / Ti3C2 MXene heterostructure exhibits the highest specific capacitance of 386.7 F g- at 1 A g-1 1. At the same time, due to the synergy in the heterostructure, it shows excellent rate performance (207.3 F g-1 at 50 A g-1). In addition, the 1T-MoS2 / Ti3C2 MXene-based all-solid flexible symmetrical supercapacitor shows a high area capacitance of 347 mF cm-2 at 2 mA cm-2. After 20 000 long-term cycles, the area capacitance of the flexible device can be maintained at about 91.1%, showing excellent cycle stability. The 1T-MoS2 / Ti3C2 MXene heterostructure can achieve strong coupling between high-capacitance 1T-MoS2 nanosheets and high-rate Ti3C2 MXene. This work paves the way for studying the electrochemical energy storage mechanism of supercapacitors in 2D / 2D heterostructures.

Literature link:
DOI: 10.1002 / adfm.201910302
Source: MXene Frontier