北京化工大学严乙铭&杨志宇Angewandte Chemie International Edition观点:自旋非对称诱导Hubbard能隙近闭合提升水系锌离子电池性能
【Article Information】
Spin electrochemical energy storage: spin asymmetry induces near-closure of the Hubbard energy gap to improve the performance of aqueous zinc-ion batteries
First Author: Wang Shiyu
Contact:YAN Yiming*,YANG Zhiyu*,XIE Jiangzhou*
Affiliation: Beijing University of Chemical Technology, University of New South Wales
【Background】
Aqueous zinc-ion batteries (ZIBs) are gradually becoming the next generation of potential electrochemical energy storage technologies due to their low cost, good safety and high theoretical capacity. Transition metal oxides (TMOs) are widely used as electrode materials for ZIBs due to their wide operating voltage range, environmental friendliness and wide range of sources. However, as semiconductor materials, the inherent Hubbard energy gap (Eg) of TMOs limits the electron transport efficiency, resulting in slow progress in the reaction kinetics of ZIBs.
【Introduction】
北京化工大学严乙铭教授、杨志宇副教授课题组在国际知名期刊Angewandte Chemie International Edition上发表题为“Spin Symmetry Breaking-induced Hubbard Gap Near-Closure in N-coordinated MnO2 for Enhanced Aqueous Zinc-Ion Battery Performance“的观点文章。 该观点的核心在于通过自旋态调控，改变了Mn eg轨道的占据态，进而实现Hubbard能隙的近闭合。 制备得到的TEAMO电极材料，具有优异的电化学性能，可以用于ZIBs的正极材料。 该研究从电子自旋属性的角度深入理解了TMOs材料的电子结构和电化学性能的关系，为设计先进ZIBs电极材料提供了可借鉴的策略。
【Main points of the text】
Point 1. Theory guides the design of the reaction mechanism
The charge transfer process in electrochemical energy storage is closely related to the electronic configuration of the material, especially when it comes to spin-related charge transfer and orbital interactions. In MnO2, the symmetrical distribution of spintrons limits the development of spin polarization (Fig. 1c), resulting in Mott semiconductor properties. The authors enhanced the d-orbital occupancy by axial coordination, which promoted the redistribution of electron density and spin polarization, resulting in the formation of a uniform Hubbard band. This process enhances the electron transport capacity and enhances the MnO2 reaction kinetics.
Point 2.Spintron configuration reset before and after surface morphology and structural details
The authors describe the synthesis process of TEAMO and characterize the crystal structure, elemental composition and morphology of the material by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and other techniques
Point 3. Characterization of spin-dependent electronic structures
Through M-T test, XAS spectroscopy, PDOS, UPS spectroscopy and other experimental characterization methods and theoretical calculations, the authors successfully prove that the spin symmetry breaking in TEAMO effectively enhances the occupation of Mneg orbitals, fills the dz2 orbital occupation and broadens the width of dx2-y2 orbitals near the Fermi level. This change in electronic structure improves the electronic conductivity and structural stability of the material, and comprehensively improves the electrochemical performance of waterborne zinc-ion batteries.
Point 4. Characterization of electrochemical properties
The cyclic voltammetry (CV) curve, constant current charge/discharge (GCD) curve, rate performance and cycle stability of TEAMO and MnO2 cathode materials were demonstrated, highlighting the superior performance of TEAMO in aqueous zinc-ion batteries.
Figure 5. Kinetic analysis
Through a series of electrochemical experiments and DFT simulations, the kinetics of teamo and MnO2 were analyzed, and the faster reaction kinetics and ion transport capacity of teamo were revealed.
Fig.6 Analysis of energy storage mechanism and dynamic efficiency mechanism
Combined with in-situ Raman testing, in-situ XRD testing and in-situ sXAS testing, the authors deeply explored the structure and morphological evolution of the prepared teamo electrode during charge-discharge cycles, elucidated the charge storage mechanism of Zn/MnO2 batteries, and evaluated its stability. The results show that the near-closure of the Hubbard energy gap in TEAMO has dual advantages in optimizing charge transfer dynamics and enhancing structural stability.
Through the in-depth study of this work, the authors revealed the effect of electron spin symmetry of TMOs materials on inducing the closure of the Hubbard energy gap. This spin-electrochemical energy storage strategy can significantly enhance the storage capacity, magnification and cycling stability of electrode materials in ZIBs. The authors use a combination of theory and experiment to elucidate the electronic structure of materials, especially the complex relationship between electron spin properties and electrochemistry, which provides theoretical support for the design and development of high-performance cathode materials in advanced energy storage systems.
【Article Link】
Spin Symmetry Breaking-induced Hubbard Gap Near-Closure in N-coordinated MnO2 for Enhanced Aqueous Zinc-Ion Battery Performance
https://doi.org/10.1002/anie.202408414
【About the Corresponding Author】
Yan Yiming, professor and doctoral supervisor of Beijing University of Chemical Technology, is a national high-level talent. He is mainly engaged in electrochemical catalysis, electrochemical water treatment, and new energy materials and technology research. He has published more than 120 SCI papers. He won the first prize of Beijing Science and Technology Award and the second prize of National Natural Science Award.
Yang Zhiyu is an associate professor at Beijing University of Chemical Technology. Ph.D. from Beijing Institute of Technology, postdoctoral fellow from Tsinghua University. His main research interests are in the field of electrochemistry. His current research interests are (i) electrochemical energy storage, (ii) electrocatalytic CO2 reduction, electrocatalytic formic acid oxidation and electrocatalytic nitrogen reduction, and (iii) capacitive desalination. He has published more than 80 SCI papers, applied for 7 patents and authorized 5 patents.
Jiangzhou Xie is a postdoctoral fellow at the University of New South Wales. He holds a bachelor's and master's degree from Beijing Institute of Technology and a Ph.D. from the University of New South Wales. He is mainly engaged in electrochemical water treatment and electrochemical catalysis. He has published more than 40 SCI papers as the first author and co-corresponding author.