Cyano complex compounds as well as preparation method and application thereof

[0034] Example 1

[0035] Dissolve ammonium ferrocyanide in deionized water, stir evenly to obtain ferrocyanide ion (Fe(CN) 6 4- ) Solution A with a concentration of 0.1mol/L; add MnCl 2 Dissolve in deionized water to obtain Mn 2+ Calculate the concentration of 0.2mol/L solution B (MnCl 2 The molar ratio with ammonium ferrocyanide is 2.5); Mix solution A and solution B, hydrothermally react at 60°C for 2h, filter, wash, and dry to obtain (NH 4 ) x Mn[Fe(CN)] y Precipitation; NaCl is dissolved in a mixed solvent of ethylene glycol and deionized water (the volume ratio of the two is 90:10) to obtain a solution C with a concentration of 0.2mol/L (the molar ratio of NaCl and ammonium ferrocyanide is 2.5 ), will (NH 4 ) x Mn[Fe(CN)] y Add to solution C, after ultrasonic dispersion, react for 1.5h at 150°C under nitrogen atmosphere, then cool, filter, wash, and dry to obtain the cyano complex compound Na x Mn[Fe(CN)] y. Through ICP analysis, the x value of the product is 1.75, the y value is 0.85, the crystal lattice structure is rhombohedral phase, and the particle size is 200-400nm.

[0036] figure 1 The X-ray diffraction spectrum of the cyano complex compound prepared in this embodiment can be attributed to sodium ferromanganese cyanide.

[0037] The cyano complex compound prepared in this example was used as the positive electrode, sodium metal was used as the negative electrode, glass fiber (brand Whatman GF/D) was used as the separator, and NaPF 6 The ethylene carbonate (EC)/diethyl carbonate (DEC) solution is the electrolyte. The battery is assembled in a glove box filled with argon, and the charge and discharge test is performed. The charge and discharge curve is as follows figure 2 Shown. Constant current charge and discharge test (current density 30mA/g, voltage range 2V ~ 4V. From the figure, the capacity can reach 151mAh/g.

[0044] Example 2

[0045] Dissolve ammonium ferrocyanide in deionized water, stir evenly to obtain ferrocyanide ion (Fe(CN) 6 4- ) Solution A with a concentration of 0.2mol/L; MnCl with a molar ratio of 1:1 2 And FeSO 4 Dissolve in deionized water to obtain Mn 2+ And Fe 2+ The total concentration of solution B (MnCl 2 With FeSO 4 The ratio of the total number of moles to the number of moles of ammonium ferrocyanide is 3); Mix Solution A and Solution B, hydrothermally react at 60°C for 2h, filter, wash, and dry to obtain (NH 4 ) x Mn 0.5 Fe 0.5 [Fe(CN)] y Precipitation; NaCl is dissolved in a mixed solvent of ethylene glycol and deionized water (the volume ratio of the two is 90:10) to obtain a solution C with a concentration of 0.4 mol/L (the molar ratio of NaCl and ammonium ferrocyanide is 3 ), will (NH 4 ) x Mn 0.5 Fe 0.5 [Fe(CN)] y Add to solution C, after ultrasonic dispersion, react at 140℃ for 2h under nitrogen atmosphere, then cool, filter, wash and dry to obtain the cyano complex compound Na x Mn 0.5 Fe 0.5 [Fe(CN)] y , Where x=1.61, y=0.77; the lattice structure is rhombohedral phase, and the particle size is 200-400nm.

[0046] The cyano complex compound prepared in this example was used as the positive electrode, sodium metal was used as the negative electrode, glass fiber (brand Whatman GF/D) was used as the separator, and NaPF 6 The ethylene carbonate (EC)/diethyl carbonate (DEC) solution is the electrolyte, the battery is assembled in a glove box filled with argon, and the charge and discharge test is performed. Constant current charge and discharge test (current density 30mA/g, voltage range 2V ~ 4V, show that the capacity can reach 142mAh/g.

[0047] Example 3

[0048] Dissolve ammonium ferrocyanide in deionized water, stir evenly to obtain ferrocyanide ion (Fe(CN) 6 4- ) Solution A with a concentration of 0.1mol/L; add FeCl 2 Dissolve in deionized water to obtain Fe 2+ Calculate the concentration of 0.2mol/L solution B (FeCl 2 The ratio of moles to ammonium ferrocyanide is 3); Mix solution A and solution B, hydrothermally react at 60℃ for 2h, filter, wash, and dry to obtain (NH 4 ) x Fe[Fe(CN)] y Precipitation; NaCl is dissolved in a mixed solvent of ethylene glycol and deionized water (the volume ratio of the two is 90:10) to obtain a solution C(N) with a concentration of 0.2mol/L a The molar ratio of Cl and ammonium ferrocyanide is 2.5), the (NH 4 ) x Fe[Fe(CN)] y Add to solution C, after ultrasonic dispersion, under nitrogen atmosphere, after reacting at 160℃ for 1 hour, then cooling, filtering, washing and drying, the cyano complex compound Na is obtained x Fe[Fe(CN)] y In the formula, x=1.72, y=0.83; the crystal lattice structure is rhombohedral phase, and the particle size is 200-400nm.

[0049] The ferrocyanide-based positive electrode material prepared in this example was used as the positive electrode, sodium metal was used as the negative electrode, glass fiber (brand Whatman GF/D) was used as the separator, and NaPF 6 The ethylene carbonate (EC)/diethyl carbonate (DEC) solution is the electrolyte, the battery is assembled in a glove box filled with argon, and the charge and discharge test is performed. Constant current charge and discharge test (current density 30mA/g, voltage range 2V ~ 4V, show that the capacity can reach 148mAh/g.