Recently, the Advanced Energy Catalytic Functional Materials Research Group led by Professor Zhang Jiannan of the School of Materials Science and Engineering of Zhengzhou University and the research group of Deng Dehui, a researcher at the Dalian Institute of Chemical Physics of the Chinese Academy of Sciences, jointly published the "Evolution of the solid electrolyte interphase enabled by FeNX/C" in the top international journal "Energy & Environmental Science" Catalysts for sodium-ion storage" original research paper. Professor Zhang Jiannan and Researcher Deng Dehui are the co-corresponding authors of the paper, Doctoral student Xia Huicong is the first author of the paper, and school of materials science and engineering of Zhengzhou University is the first author unit and communication unit of the paper.
The structure and chemical engineering of the solid electrolyte interface (SEI) has a critical impact on the performance of battery electrode materials. Therefore, in-depth study of the formation mechanism, composition structure, stability and influencing factors of SEI membranes, and further finding effective ways to improve the performance of SEI membranes, has always been a hot spot in the world electrochemical community. In fact, the potential link between the enhanced sodium storage characteristics of the metal-nitrogen (MNX) platform electrode and SEI has not yet been resolved during the charge-discharge cycle.
This study found that good electronic structure gives FeNx a catalytic effect on the reversible process of SEI, which helps to store additional sodium ions. The conversion of NaF intermediates containing surface halides into FeF3 in SEI is the key to the capacity of fe atoms. In addition to this, based on the findings of the non-in situ XPS and in situ temperature-dependent Nyquist diagrams, the authors confirmed that the additional capacity is provided by the reversibility of organic and inorganic components in SEI. In addition, the contribution of surface capacitance effects and the intercalation/decoupling process of sodium ions on the surface of carbon-based materials is indelible. A series of characterizations suggest that Fe-NX is essential for fef3 generation and subsequent conversion of SEI. In addition, optimized Fe3C nanoparticles greatly facilitate this process due to rapid electron transport dynamics. While more electrons are processed by further regulating various Fe species, this in turn promotes the production of SEI and inhibits the production of unstable components.
This work not only provides a new direction for the design of carbon composite nanomaterials in the application of the next generation of high-performance energy storage devices, but also provides some guidance for in-depth analysis of the beneficial effects of SEI membranes in electrochemical energy. This work was supported by the National Natural Science Foundation of China, the Central Plains Youth Top Talents, and the Zhengzhou University Youth Innovation Team Support Program.
Source: Zhengzhou University
Full-text links:
https://pubs.rsc.org/en/content/articlelanding/2022/ee/d1ee02810c