【Article Information】
Ultra-long-lived zero-cobalt/nickel-Prussian blue analogue cathode achieved by solution reaction sodium storage mechanism
First Author: Wang Yichao
Contact: YANG Cheng*, LIU Yu*
Affiliation: Shanghai Institute of Ceramics, University of Chinese Academy of Sciences
【Background】
Due to the high redox potential and electrochemical activity of manganese (Mn), sodium-rich monoclinic manganese-based Prussian blue compounds (Mn-PBAs) are regarded as strong competitors in the Prussian blue cathode. However, Mn-PBAs face the problems of poor cycle reversibility and low capacity retention ability in practical use, which is mainly due to the dissolution of Mn elements in the electrolyte, and the monoclinic phase Mn-PBAs will undergo unfavorable multiphase transition (monoclinic cubic ↔ phase ↔ tetragonal phase) throughout the cycle, accompanied by severe lattice distortion, which will lead to the accumulation of local fracture and degradation in Prussian blue, resulting in the formation of microcracks and damaged particles. These processes lead to a series of detrimental effects on the cathode of Mn-PBAs, including chemical corrosion/dissolution from surface to body relative to Prussian blue, formation and growth of new cathode electrolyte interfaces (CEIs) in intergranular fractures, and continuous growth and structural degradation of Prussian blue.
【Introduction】
In this work, Prof. Yu Liu's team successfully prepared ternary Prussian blue compounds (T-PBAs) with initial cubic phase by synergistically incorporating low-cost copper (Cu) and iron (Fe) into the manganese site of Mn-PBAs, and realized the solid solution reaction of Na+ storage during the charge-discharge process. It was confirmed by ex situ analysis and density functional theory (DFT) calculations that T-PBAs always maintained the cubic phase during the charge-discharge process and had small lattice distortion, which effectively inhibited the structural degradation of T-PBAs, and therefore, T-PBAs exhibited unprecedented cycling stability at room temperature (10,000 cycles at 1A g-1) and -20°C (more than 3,000 hours, 4,200 cycles at 0.2A g-1 with no significant capacity decay).
更重要的是，当与商用硬碳配对时，基于T-PBAs的钠离子电池（SIBs）表现出优异的容量保持能力（2,000次循环后保持76.8%），展现了其在实际应用中的巨大潜力。 该成果以“Ultralong Lifespan Zero-Cobalt/Nickel Prussian Blue Analogs Cathode Realized by Solid Solution Reaction Sodium Storage Mechanism“为题发表在国际知名期刊Advanced Functional Materials上，第一作者为中科院上海硅酸盐研究所2022级硕士生王逸超。
【Research Topics】
图1. a) XRD图谱的Rietveld精修;b) 立方晶体结构模型;c) SEM图像;d) TEM图像;e) SAED图谱;f) HRTEM图像;g) T-PBAs的EDS元素分布图。
The refinement results of XRD show that the Prussian blue is typically cubic and the synthesized T-PBAs have cubic morphology. The crystal structure of T-PBAs was further investigated by selective electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM) analysis. As shown in Figures 1e and 1f, the (200)/(220) planes are clearly discernible in the cubic structure of the T-PBAs, which is consistent with the XRD results. The distribution of all elements in the T-PBAs was verified by SEM energy dispersive spectroscopy (EDS) mapping (Figure 1g), confirming the uniform distribution of the elements in the particles.
Figure 2. a) Second charge-discharge curves of all samples at 0.02A g-1; b) the first five charge-discharge curves of T-PBAs at 0.02A g-1; c) CV curve of T-PBAs at 0.2 mV s-1; d) Rate performance of all positive electrodes; e) Calculated Na+ diffusion coefficient; f) CV pattern contour plots of T-PBAs at different scan rates; g) Plot of log (I) vs. log (V) in CV results; h) Cycling performance of the sample at 0.5A g−1; i) the median voltage of the sample; j) 1 A g−1 long-term cycling performance of T-PBAs after 10 cycles at 0.1 A g−1; k) Comparison of the capacity and cycling performance of various electrodes.
Electrochemical testing of half-cells has demonstrated excellent electrochemical properties of cubic Prussian blues (T-PBAs), including fast sodium ion diffusion rate, excellent rate performance, and cycling stability.
Fig.3 a-b) Ex-situ XRD patterns collected during the first charge and discharge of T-PBAs/Na half-cells at 10 mA g−1 in the voltage range of 2.0–4.0 V; c-d) Ex-situ XRD patterns collected by FeMn-PBAs/Na half-cells under the same conditions; e) the change in unit volume during the first charge and discharge; f) Schematic diagram of structural evolution; g) Surface projection of 3D color image of non-in-situ Raman image; h) XRD patterns of T-PBAs after different cycles; i) XRD profiles of FeMn-PBAs after different cycles; j) XRD patterns of CuMn-PBAs after different cycles.
The solution reaction of T-PBAs during the charging and discharging process realizes the zero phase transformation in the process of sodium storage, significantly reduces the lattice distortion in the process of cycling, and inhibits the structural degradation of Prussian blue during the cycling process.
图4 a) Mn在初始、4.0 V和2.0 V下的非原位XPS分析;b) Fe在初始、4.0 V和2.0 V下的非原位XPS分析;c) Cu在初始、4.0 V和2.0 V下的非原位XPS分析;d) T-PBAs的投影态密度(PDOS);e) Na+提取过程中M–N键长的变化。
The ex situ XPS proves that all elements have electrochemical possibilities in T-PBAs, and the DFT calculations further prove that they have a smaller lattice distortion during the charge-discharge process.
Fig. 5 a-d) Gas evolution curves of T-PBAs obtained by DEMS; e) SEM images of all electrodes before and after 2000 cycles; f) Schematic diagram of solution reaction inhibition of by-product formation and microcrack formation of PBAs; g) In-situ EIS plot of T-PBAs in the first cycle at 0.01 A g-1; h) distribution of relaxation time in T-PBAs/Na half-cells; i) the cathode-electrolyte interface of T-PBAs; j) cathode-electrolyte interface of FeMn-PBAs; k) The cathode-electrolyte interface of CuMn-PBAs.
Fig.6 a) Schematic diagram of the whole battery; b) Voltage matching of charge-discharge constant current curves of T-PBAs//Na and HC//Na; c) Charge-discharge curves of T-PBAs//HC whole cells at different rates; d) Charging and discharging of T-PBAs//HC batteries at different rates; e) Long-cycling performance of T-PBAs//HC whole cells (specific capacity is calculated from the active mass of T-PBAs).
The whole cell assembled by T-PBAs also exhibits ultra-long cycle stability, proving its value in practical applications.
【Article Link】
Ultralong Lifespan Zero-Cobalt/Nickel Prussian Blue Analogs Cathode Realized by Solid Solution Reaction Sodium Storage Mechanism
https://doi.org/10.1002/adfm.202406809
【About the Corresponding Author】
Yu Liu's Profile: From 2002 to 2008, he worked at Mie University and Central Research Institute of Electric Power in Japan, researching related energy materials and device technologies including lithium (ion) batteries and fuel cells. From 2011 to 2015, he undertook the industrialization of large-capacity sodium-sulfur batteries, and served as the technical director of Shanghai Electric Soda-Sulfur Energy Storage Technology Co., Ltd. part-time, and built the first MW-level sodium-sulfur battery pilot line and 1MWh sodium-sulfur energy storage power station in China. Since 2016, he has led the development of high-safety energy storage battery technology for solid-state or quasi-solid-state (aqueous) electrolyte systems; 2 scientific and technological achievements have been successfully transformed (a single transformation exceeds 30 million yuan).
His research interests include energy storage secondary batteries and related new energy conversion, storage materials and devices, energy storage mechanisms and related interface electrochemistry. In 2009, he was selected as a "Pujiang" talent in Shanghai, in 2013, he was selected as a young and middle-aged innovation leader by the Ministry of Science and Technology of the People's Republic of China, and in 2016, he was selected as an excellent technical leader in Shanghai. The main projects undertaken or participated in include: the National Natural Science Foundation of China, the major special projects of the Shanghai Municipal Commission of Economy and Information Technology, the major projects of the Shanghai Municipal Science and Technology Commission, the key deployment of the Chinese Academy of Sciences, the "973" of the Ministry of Science and Technology, and the horizontal projects of enterprises. In recent years in Angew. Chem. Int. Ed.，ACS Energy Lett，Adv. Energy Mater.，Adv. Funct. He has published more than 70 academic papers in journals such as Mater., Nano Energy, Energy Storage Mater (signed as the first author or corresponding author), and obtained more than 80 authorized invention patents and 46 authorized utility model patents.
Cheng Yang Associate Professor: He graduated from the Department of Chemical Engineering of Tsinghua University in 2015 with a bachelor's degree in engineering, and graduated from the School of Materials Science and Engineering of Shanghai Jiao Tong University with a doctorate degree in engineering in 2020. During his Ph.D., he was engaged in research on the synthesis of inorganic nanomaterials and energy storage and conversion. In 2020, he joined the Shanghai Institute of Ceramics to carry out postdoctoral research, and his main research directions include the design and synthesis of high-pressure aqueous electrolytes, the stabilization design of electrode/electrolyte interface and the research of electrochemical mechanism, etc., and the research results won the second prize of the Jiangsu Intelligent Electrical Youth Innovation and Entrepreneurship Competition and the 2nd Youth Innovation and Entrepreneurship Competition of the Jiangsu Electrical Engineering Society, and were selected into the 2020 Shanghai Super Postdoctoral Talent Incentive Program.
承担或参与的主要项目包括：国家自然科学青年基金、地方科技重大专项以及企业横向项目等。 目前，已在Angew. Chem. Int. Ed.，ACS Energy Lett，Adv. Funct. Mater.，Nano Energy，Energy Storage Mater 等SCI 学术刊物上发表论文30 余篇，其中2 篇入选ESI Highly Cited Paper，1 篇为2019 JMR Paper of the Year Award（年度优秀论文）。