期刊
SCIENCE CHINA-MATERIALS
卷 65, 期 1, 页码 105-114出版社
SCIENCE PRESS
DOI: 10.1007/s40843-021-1717-3
关键词
supercapacitors; metal-metal interaction; octahedral; tetrahedral; metal-organic frameworks
资金
- National Natural Science Foundation of China [51872204, 52072261, 22011540379]
- National Key Research and Development Program of China [2017YFA0204600]
- Shanghai Social Development Science and Technology Project [20dz1201800]
- Shanghai Sailing Program [21YF1430900]
The study synthesized spinel-structured CoZn0.5V1.5O4 with a high specific surface area through an ion-exchange process, achieving increased conductivity and stability. As a supercapacitor electrode, CoZn0.5V1.5O4 showed high cycling durability and specific capacitance, providing the possibility of enhancing electrochemical performance in transition metal oxides by designing octahedral and tetrahedral sites.
Co2VO4 with Co tetrahedrons and octahedrons of transition metal oxides has achieved progress in electrocatalysts and batteries. However, high metal-metal interactions make it challenging to maintain high reactivity as well as increase the conductivity and stability of supercapacitors. In this work, spinel-structured CoZn0.5V1.5O4 with a high specific surface area was synthesized through an ion-exchange process from the metal-organic frameworks of zinc-cobalt. Density functional theory calculations indicate that the replacement of transition metal by Zn can decrease the interaction between the transition metals, leading to a downshift in the pi*-orbitals (V-O) and half-filled a(1g) orbitals near the Fermi level, thus increasing the conductivity and stability of CoZn0.5V1.5O4. As a supercapacitor electrode, CoZn0.5V1.5O4 exhibits high cycling durability (99.4% capacitance retention after 18,000 cycles) and specific capacitance (1100 mF cm(-2) at 1 mA cm(-2)). This work provides the possibility of designing octahedral and tetrahedral sites in transition metal oxides to improve their electrochemical performance.
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