This study is led by Prof. Xiaosi Zhou and Dr. Yichen Du (School of Chemistry and Materials Science, Nanjing Normal University). CNTs/VS 4 with novel chain-like morphology were synthesized by solvothermal method. ABF-STEM and X-ray absorption near-edge structure were utilized to characterize the composite. In addition, ex situ characterization and theoretical calculations confirmed the ion deposition mechanism in CNTs/VS 4 .
VS 4 has a unique layered atomic chain structure and has the potential to become a high-performance magnesium-ion battery cathode material with high capacity and long cycle life. However, low conductivity and sluggish Mg 2+ diffusivity during cycling limit its practical application in large-scale energy storage. Herein, we use a solvothermal approach and utilizing P123 surfactant to in situ construct V–O–C covalent bonds between VS 4 nanorods and surface oxidized CNTs interfaces.
“There are many carbonyl groups on the surface of oxidized CNTs, during the solvothermal process, the V source was absorbed on the surface oxidized CNTs, nucleated on the CNTs, and reacted to generate VS 4 . Raman and XPS tests confirmed the presence of the V–O–C covalent bonds at interface, which promoted the tight bonding between VS 4 and CNTs, helping to maintain structural stability during cycling, thereby extending cycle life. Additionally, ex situ characterization and theoretical calculations confirmed the reversible deposition of Mg 2+ and MgCl + , further reduced the polar barrier for divalent ion transport.” Zhou says.
In summary, this rationally designed architecture promotes ion diffusion and electron transfer, thus facilitating reaction kinetics. CNTs/VS 4 exhibits excellent magnesium storage properties, including a high reversible capacity of 223.2 mAh g −1 at a current density of 50 mA g −1 , a remarkable discharge capacity of 91.8 mAh g −1 even at 2000 mA g −1 , and an impressive capacity retention of 85.2% after 1000 cycles at 500 mA g −1 . Moreover, this cooperative assembly-oriented strategy can be used as a versatile method to creatively obtain various VS 4 /carbon nanocomposites with unique morphological structures, and provides a new approach for the development of transition metal sulfide/carbon composite electrode materials.
See the article:
A universal cooperative assembly-oriented strategy for VS 4 nanorods decoration on carbon nanostructures with enhanced magnesium storage properties
https://doi.org/10.1007/s11426-024-2195-2
Science China Chemistry