Prof. Wei Yan, Prof. Jiujun Zhang, Review of Nano Energy: Performance degradation mechanism and mitigation strategies at the interface between hard carbon anode and solid electrolyte in sodium-ion batteries
【Article Information】
Performance degradation mechanism and mitigation strategies at the interface between hard carbon anode and solid electrolyte in sodium-ion batteries
First author: Qiu Ruoxue
Contact: YAN Wei*, ZHANG Jiujun*
Affiliation: Fuzhou University
【Background】
Hard carbon has excellent sodium storage performance and is undoubtedly one of the best choices for anode materials for sodium-ion batteries. In this paper, we summarize the research progress of SIBs hard carbon anodes, SEIs formed, degradation mechanisms, and mitigation strategies to reduce degradation from the following three aspects: (1) the basic understanding of the sodium storage mechanism of hard carbon from different modes such as sodium ion adsorption/insertion and pore filling in hard carbon materials; (2) The understanding of the structure-property relationship of hard carbon anodes based on the design, synthesis, theoretical characterization and performance optimization of new materials provides a potential approach for the design of high-performance SIBs anodes. and (3) challenges associated with the degradation of SEI formed between the hard carbon anode and its surface, and mitigation strategies to reduce degradation. It is hoped that the research results in this paper can provide valuable guidance for the research and commercial development of SIBs hard carbon anodes.
【Introduction】
近日，来自福州大学的颜蔚教授和张久俊院士，在国际知名期刊Nano Energy上发表题为“Performance degradation mechanisms and mitigation strategies of hard carbon anode and solid electrolyte interface for sodium-ion battery”的综述文章。 该文章首先对硬碳的结构和目前已知的钠储存模型进行深入的探讨，其次详细综述了近几年SIBs中硬碳的结构-性能关系的相关问题与研究进展，包括设计硬碳微观结构参数、绿色低成本合成路线等以增加硬碳负极的实际应用性，并促进SIBs的商业化发展。
Figure 1. Factors influencing the electrochemical performance of hard carbon anode in sodium-ion batteries.
【Main points of the text】
Point 1: The sodium ion storage mechanism of the hard carbon anode
The diversity and complex microstructure of hard carbon precursors make it difficult to explore the correlation between Na+ storage behavior and performance. However, the development of high-performance SIBs hard carbon anodes relies on a clear and comprehensive understanding of the material structure and Na storage process. Here, the sodium storage mechanism in the hard carbon anode is first discussed in depth. At present, the Na+ storage mechanism of HC is divided into the following four models, including the "embedding-adsorption model", "adsorption-embedding model", "adsorption-pore filling model" and "adsorption-embedding-pore filling model". The debate over the hard carbon storage mechanism has focused on the source of the capacity of the low-voltage plateau in the discharge/charge curve, whether it is the result of interlayer embedding, closed pore filling, or the adsorption-embedding-pore filling model of both. These controversial controversies have generated a great deal of interest in a deeper understanding of the structure and storage processes of hard carbon.
Point 2: Effect of hard carbon microstructure on sodium storage performance
High energy density and low cost sodium-ion batteries are in demand, which requires a high operating potential and a large reversible specific capacity of the whole battery. For hard carbon materials, the increase in the capacity of the low-pressure platform section is particularly crucial. In general, increasing the number of hard carbon surface openings and defects can increase the capacity of the high-pressure inclined section, which is conducive to the improvement of rate performance, but has little effect on the improvement of energy density, and will greatly affect the first coulombic efficiency. Reasonable construction of closed cells and increasing the spacing of graphite-like layers can improve the sodium storage capacity of the low-pressure platform section, but the rate performance is often affected. Therefore, it is difficult to improve the energy density at the same time as the first coulombic efficiency and rate performance, and it is still necessary to continue research. Based on the literature reported in recent years, this chapter discusses in detail three strategies for improving the specific capacity of hard carbon anodes, namely graphite-like domain control, defect control, and nanopore control, in the hope that it can provide ideas for the design and application of high-performance sodium-ion anode materials.
Point 3: Interface design of solid electrolyte for hard carbon anode
The solid electrolyte interface (SEI) is a complex heterostructural passivation layer that plays a crucial role in the performance of sodium-ion batteries. The formation of SEI is largely affected by the electrode and electrolyte, and a complete and stable SEI can limit electron tunneling and prevent electrolyte reduction to maintain the electrochemical stability of the battery. In addition, the effect of ion-solvent interaction on the stability of the electrolyte can be reflected by the LUMO/HOMO energy level. The formation of SEI on the surface of the anode mainly depends on the LUMO energy level related to the reduction process, while the HOMO energy level is related to the oxidation reaction that occurs on the electrode surface. During the cycling of the battery, the loose and porous SEI will continue to consume the electrolyte to form a thickening SEI layer, which will increase the resistance of the battery and decay the capacity, and eventually lead to battery failure. Therefore, how to build an efficient and stable SEI on HC is a key problem to be solved to achieve high-performance SIB.
Point 4: Summary and outlook
In this review, we first take a closer look at the structure of hard carbon and the currently known sodium storage models. Defects, short-range ordered turbulent graphite crystallites, and the resulting nanopores constitute the microstructure of hard carbon, which largely directly affect the electrochemical properties of hard carbon anodes. Secondly, the relevant problems and research progress of the structure-property relationship of hard carbon in SIBs in recent years are reviewed in detail, including the design of HC microstructure parameters and green low-cost synthesis routes to increase the practical applicability of hard carbon anodes and promote the commercial development of SIBs. Finally, the method and related advantages of solid electrolyte interface (SEI) design of hard carbon anode are discussed, and a more stable interfacial phase can be established through solvent/salt selection, electrolyte concentration control, and functional additives to achieve ideal electrochemical reversibility. We hope that this review can provide useful design ideas for the realization of high-capacity hard carbon anodes and provide a theoretical basis for the industrialization of SIBs.
【Article Link】
“Performance degradation mechanisms and mitigation strategies of hard carbon anode and solid electrolyte interface for sodium-ion battery”
https://www.sciencedirect.com/science/article/abs/pii/S2211285524006682
【About the Corresponding Author】
Prof. Wei Yan's B.S. in Electrochemistry from Wuhan University in 1998 and Ph.D. in Analytical Chemistry from Wuhan University in 2005. In 2007, he was a postdoctoral fellow in the School of Chemistry and Chemical Engineering of Nanjing University, and joined the School of Science of Shanghai University as the vice president and associate researcher of the Institute of Sustainable Energy. He joined Fuzhou University in January 2022 as the executive dean and researcher of the Institute of New Energy Materials and Engineering. Mainly engaged in electrochemical energy storage and conversion: including Li/Na/K alkali metal ion batteries, Li/Na/K alkali metal batteries, metal-air batteries, lead-carbon batteries and supercapacitors.
Professor Zhang Jiujun is a foreign academician of the Chinese Academy of Engineering, an academician of the Royal Society of Canada, an academician of the Canadian Academy of Engineering, an academician of the Canadian Academy of Engineering, a fellow of the International Electrochemical Society, a fellow of the Royal Society of Chemistry, a fellow of the International Association for Advanced Materials, the chairman of the International Academy of Electrochemical Energy Sciences (IAOEES), an executive director of the Chinese Society of Internal Combustion Engines and the chairman of the Fuel Cell Engine Branch. Professor Zhang has long been engaged in the research and industrial application development of electrochemical energy storage and conversion and its materials, including fuel cells, high-energy rechargeable batteries, supercapacitors, CO2 electrochemical reduction and water electrolysis.
至今已发表论文及科技报告700余篇，编著书28本，书章节47篇，被引用81700多次（H-Index为125）。 目前是Springer-nature《Electrochemical Energy Reviews》SCI期刊主编、CRC Press《Electrochemical Energy Storage and Conversion》丛书主编、KeAi Publishing《Green Energy & Environment》SCI期刊副主编、中国工程院院刊《Frontiers In Energy》期刊副主编、中国化学化工出版社大型丛书《电化学能源储存和转换》及《氢能技术》主编及多个国际期刊的编委。
【First Author Introduction】
Ruoxue Qiu is a 2023 Ph.D. student in the School of Materials Science and Engineering/Institute of New Energy Materials and Engineering, Fuzhou University, under the supervision of Academician Zhang Jiujun and Professor Yan Wei. His main research direction is sodium-ion batteries.