Thermal reduction of MAX phase to prepare MXene nanosheets for high-performance lithium batteries

 As an important part of the emerging two-dimensional nanomaterials , two -dimensional MXene has received extensive attention in recent years, especially in the energy-related fields. Unfortunately, due to the usual use of dangerous etchants, the controlled synthesis of MXenes with higher purity remains a challenge. I am looking forward to proposing a simple, controllable and effective method for green production of MXene .

Achievements

Recently, the Queensland University of Technology of Sunzi Qi professor and Southwest Jiaotong University ‘s Professor Hu Chunfeng in the internationally renowned journal Chemical Engineering Journal published entitled " Thermal Reduction of sulfur-containing MAX Phase for MXene Production‘s " papers. In this work, a thermal reduction strategy was innovatively proposed to prepare MXenes nanosheets from the sulfur-containing MAX phase, in which weakly bonded S atoms reacted with hydrogen to form volatile gases, leaving behind two-dimensional graphene-like Ti 2 C nanosheets. As a promising electrochemical anode material, the MXene-based lithium battery has a good initial discharge capacity, about 200 mAh g ⁻¹ . In addition, the capacity remained at 70 mAh g ⁻¹ after more than 130 cycles at 2.0 A g ⁻¹ , demonstrating good rate performance and cycle stability. Therefore, this work provides a new method for the preparation of MXene and enriches the MXene-based electrode materials for energy devices.

Figure  1  Schematic diagram of preparation of 2D Ti 2 C MXene .

Figure  2  The crystalline form after reducing the sulfur-containing MAX phase at different temperatures .

Figure  3  The morphology and structure of the sulfur-bearing MAX phase at different temperatures .

Figure  4.  Morphology and structure of Ti 2 C MXene after ultrasound .

FIG  5  before and after the thermal reduction 2D of Ti 2 C MXene the XPS peak separation.

Figure  6  Electrochemical properties of 2D Ti 2 C MXene .

Figure  7  Nyquist and TEM images of 2D Ti 2 C MXene after cycling .

in conclusion

       In summary, a novel method for preparing MXenes nanosheets from the sulfur-containing MAX phase through thermal reduction strategy was innovatively proposed . Experiments show that the optimal reduction temperature is 800 ℃, and the obtained MXene has a clear two-dimensional sheet structure. The prepared MXene -based lithium battery has a good initial discharge capacity, about  200 mAh g ⁻¹ . In addition, the capacity remains at 70 mAh g ⁻¹ after more than 130 cycles at 2.0 A g ⁻¹ , demonstrating good rate performance and cycle stability. This work promotes MXene the large-scale preparation and MXene industrial applications based rechargeable battery material.

Original link:

https://www.sciencedirect.com/science/article/pii/S1385894720311037

Source: MXene Academic

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