Adv. Energy Mater.｜Vertical Alignment of MXene Nanosheet Arrays to Regulate Li Metal Nucleation and Growth

已传文件：photo/1631586161.png North Konami can provide vertically aligned MXene nanosheets (customizable)
Research abstract

Lithium metal is considered to be an optimal anode material system thanks to its higher theoretical capacity and lower reduction potential. However, the inhomogeneous Li metal dendrite growth greatly limits its practical application. In view of this, the research team of Professor Zhang Xiaokun of University of Electronic Science and Technology of China, Professor Yang Shubin and Professor Gong Yongji of Beihang University published research results in "Advanced Energy Materials", reporting a vertically aligned Ti3C2Tx prepared by ice template-assisted doctor blade coating method MXene nanosheet arrays to regulate Li metal nucleation and induce Li metal deposition. This vertical structure exhibits a low degree of bending, which in turn enables fast lithium transport. In addition, the abundant -F and -O functional groups on the surface of Ti3C2Tx facilitate the formation of a uniform solid-state electrolyte interfacial layer, which is very important for controlling the nucleation and growth of Li metal. Therefore, this vertically aligned Ti3C2Tx MXene electrode can produce a capacity of 1.0 mAh cm-2 with a high Kunlun efficiency (98.8%) after 450 cycles at an areal current density of 1.0 mA cm-2, even at ultra-high Stable lithium deposition and exfoliation behaviors can be achieved at a high areal current density of 5.0 mA cm-2, and the areal capacity is as high as 5.0 mAh cm-2. When matched with the lithium iron phosphate cathode to assemble the full battery, it showed excellent stability and rate performance.

Graphical guide







Figure 1. Synthesis route and characterization of v-Ti3C2Tx electrodes.






Figure 2. Investigation of SEI layers on different electrodes.





Figure 3. Morphological evolution of v-Ti3C2Tx electrode and comparative electrode during Li plating and stripping.





Figure 4. COMSOL simulation of lithium deposition behavior of v-Ti3C2Tx electrode and h-Ti3C2Tx electrode.





Figure 5. Electrochemical performance test results of v-Ti3C2Tx electrode and h-Ti3C2Tx electrode.



Summarize


The results show that the low curvature of this vertically aligned MXene array not only homogenizes Li ions with the electric field, but also enriches the active surface area for Li deposition. The optimized SEI layer is rich in Li2O and LiF, which is mainly due to the abundant -O and -F functional groups on the surface of MXene, which are of great significance for the nucleation and growth regulation of lithium metal. Compared with horizontally aligned MXenes,1 this vertically aligned MXene electrode can improve the cycling stability and rate capability of half-cell and full-cell devices. This unique design realizes the perfect combination of low-curvature structure and SEI layer modification, which provides an easy-to-process strategy for the development of Li metal anodes.


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Literature link

https://doi.org/10.1002/aenm.202200072

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