Shulou(Shulou.com)11/24 Report--

Thanks to CTOnews.com netizen Xiao Zhan for the clue delivery! CTOnews.com, April 11, CTOnews.com learned from the official website of the National Synchrotron radiation Laboratory of the University of Science and Technology of China that Professor Song Li's team in the laboratory proposed the concept of VT2g orbital occupation induced by intercalation agent based on the synchrotron radiation spectroscopy characterization of intercalated zinc ion battery cathode materials, and developed ammonium intercalated vanadium pentoxide zinc ion battery cathode materials with fast charging performance. The relevant results were recently published in the international academic journal Proceedings of the National Academy of Sciences.

Water zinc ion battery (ZIBs) has become one of the most potential sustainable energy storage technologies because of its safety, non-toxicity and high theoretical capacity. Among many ZIBs electrode materials, layered vanadium oxide has the characteristics of adjustable crystal structure and high capacity, so it is a widely studied cathode material at present. The ion or molecular pre-intercalation strategy can effectively solve the problems of insufficient lattice space and low electronic conductivity of cathode materials, so as to further improve the performance of the battery. However, the current research on intercalated cathode materials focuses on the contribution of interlayer space expansion to capacity. Therefore, the development of advanced in-situ characterization technology and in-depth understanding of the internal structure changes of electrode materials caused by intercalation agents from the aspect of atomic orbitals is the key to the design and development of high-performance cathode materials in the future.

Figure 1. It is applied to the Vt2g orbital occupation mechanism of high performance ZIBs cathode material NH4+-V2O5.

Figure 2. It is applied to the analysis of NH4+-V2O5 energy storage mechanism of high performance ZIBs cathode materials. In this work, taking the advantage of Synchrotron radiation (Synchrotron radiation) as a comprehensive experimental platform, combined with a variety of in-situ and non-in-situ synchrotron radiation spectroscopy techniques, the change of V-3dt2g orbital occupation in V2O5 after ammonium ion (NH4+) intercalation and the reversible evolution during charge and discharge were revealed. It is found that the NH4 + intercalation induces the structural distortion of the VMI O bond to a great extent, which further leads to the rearrangement of the electronic structure and the occupation of the 3dxy vacancy in the Vt2g orbital. The Vt2g orbital occupation greatly improves the electrical conductivity of the material, and broadens the interlayer spacing after intercalation with NH4 +, which significantly accelerates the transfer of zinc ion (Zn2+) and achieves the ultra-high rate performance of zinc ion battery.

The test results show that when the current density is 200C, the specific capacity of ammonium intercalated vanadium pentoxide (NH4+-V2O5) cathode material is still maintained at 101.0 mA / h, and the charging time is only 18 s. This work not only provides a basis for understanding the energy storage mechanism of Zn2 + in intercalated V2O5 materials in terms of atomic orbitals, but also lays a foundation for the application of high-performance zinc ion batteries in fast charge energy storage devices.

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