Prussian blue and analogue thereof, and defect repair method and application thereof

Abstract

The invention discloses Prussian blue and an analogue thereof, and a defect repairing method and an application thereof. The method comprises the steps: (1) dissolving salt containing ferrous cyanide ions into a deionized water solution to obtain a salt solution; and (2) soaking the Prussian blue and the analogue thereof in the salt solution, continuously stirring for a preset time, standing to obtain a precipitate, and cleaning and drying the precipitate to obtain the Prussian blue and the analogue thereof which are subjected to defect repair. According to the method, the [Fe(CN)6]<4-> vacancy defect existing in traditional Prussian blue and the analogue thereof is directly repaired by using the salt solution containing ferrous cyanide anions, and anion regulation is realized, so that the vacancy defects of the Prussian blue and the analogue thereof are reduced, the crystal water is reduced, and the phase structure is more complete. The repaired Prussian blue material can be used as a sodium-ion battery positive electrode material, and the cycling stability and the charge-discharge specific capacity of the sodium-ion battery positive electrode material are greatly improved.

Description

technical field [0001] The invention belongs to the field of Prussian blue and its analogs, and more specifically relates to a Prussian blue and its analogs, a defect repairing method and applications thereof. Background technique [0002] The simple preparation process is an important feature of the Prussian blue material. The main synthesis methods of iron-based Prussian blue can be divided into single iron source solution method and double iron source co-precipitation method. In 2014, researcher Guo Yuguo and his colleagues used Na 4 Fe(CN) 6 As the sole iron source, low-defect Na 0.61 Fe[Fe(CN) 6 ] 0.94 Cathode material for sodium storage, showing very high specific capacity of sodium storage and good cycle stability (Ya You, Xing-Long Wu, Ya-Xia Yin, and Yu-Guo Guo, High-quality prussian blue crystals as superior cathode materials forroom-temperature sodium-ion batteries, Energy&Environmental Science, 2014, 7, 1643); in 2015, the team of Professor Goodenough, the ...

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Problems solved by technology

In 2014, researcher Guo Yuguo and his colleagues used Na 4 Fe(CN) 6 As the sole iron source, low-defect Na 0.61 Fe[Fe(CN) 6 ] 0.94 Cathode material for sodium storage, showing very high specific capacity of sodium storage and good cycle stability (Ya You, Xing-Long Wu, Ya-Xia Yin, and Yu-Guo Guo, High-quality prussian blue crystals as superior cathode materials forroom-temperature sodium-ion batteries, Energy&Environmental Science, 2014, 7, 1643); in 2015, the team of Professor Goodenough, the Nobel Laureate in Chemistry, used Na 4 Fe(CN) 6 As a single iron source, a sodium-rich sodium-storage cathode Na was obtained via a hydrothermal synthesis method 1.92 Fe[Fe(CN) 6 ], which can provide a specific capacity of 157 mA / g at a current density of 15 mA / g (L.Wang, J.Song, R.Qiao, L.A.Wray, M.A.Hossain, Y.D.Chuang, W.Yang, Y.Lu, D.Evans, J.J.Lee, S.Vail, X.Zhao, M.Nishijima, S.Kakimoto and J.B.Goodenough, Rhombohedral Prussian White as Cathode for RechargeableSodiumIon Batteries, Journal of the American Chemical Society, 2015, 137, 2548 -2554.). However, the single iron source solution method is not suitable for large-scale preparation of iron-based Prussian blue due to the release of toxic ions and low yield during the preparation process

[0004] Among the above-mentioned methods, the single-iron source solution method generates larger product particles and high quality, but the yield is low, the reaction time is very long, and it is easy to release toxic substances; the double-iron source co-precipitation method has a higher yield, but There is often a large amount of [Fe(CN) 6 ] 4- Vacancy defects and coordinated water, which can seriously affect the structural integrity of the material

Coordinated water may occupy vacancies and block the three-dimensional open channels of iron-based Prussian blue, especially when used as an electrode material, coordinated water may move during the electrochemical process, resulting in the collapse of the Prussian blue structure

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