The present invention provides a method of preparing a graphene-wrapped cobalt Prussian blue nano-crystalline composite material, and a method of preparing a working electrode using the same and an application thereof. The preparation method of the composite material includes: dispersing a ligand solution containing cobalt and a graphene oxide solution in an aqueous solution fully by stirring and ultrasonication, next, adding a cobalt metal salt solution and fully stirring, and then calcining the mixture in an inert atmosphere after centrifugation and lyophilization to obtain the above composite material. The preparation method of the present invention is simple in operation, low in energy consumption and low in material costs and the like. The composite material is obtained by uniformly and closely wrapping cobalt Prussian blue nano-crystals in graphene with excellent conductivity, thereby significantly improving electron transfer efficiency and active site utilization rate of the composite material.

A desalination cell including an electrode including a material having at least one compound of the following formula: A.sub.xM.sup.I.sub.yM.sup.II.sub.z(CN).sub.6, where A is Na, Li or K, 0≤x≤2, M.sup.I is a first metal, M.sup.II is a second metal, 1≤y, and z≤2. The material is configured to reduce calcium carbonate formation and/or carbon dioxide gas formation during operation of the desalination cell. The first metal may be Fe, Mn, Co, Sc, Ti, Cr or Zn. The second metal is Fe, Mn, Co, Sc, Ti, Cr or Zn. The first metal may be different than the second metal.

A method for synthesising a molecular magnetic material from a paramagnetic reactant including a d-electron metal in a paramagnetic form, a diamagnetic reactant comprising a d-electron metal in a diamagnetic form, and at least one donor of cyanide (CN—) ligands being a separate compound and/or contained in the paramagnetic reactant and/or in the diamagnetic reactant.

A method for synthesising a molecular magnetic material from a paramagnetic reactant including a d-electron metal in a paramagnetic form, a diamagnetic reactant comprising a d-electron metal in a diamagnetic form, and at least one donor of cyanide (CN—) ligands being a separate compound and/or contained in the paramagnetic reactant and/or in the diamagnetic reactant.

The present invention provides a process for the regeneration of an electrolyte solution of a redox-flow battery containing at least one (preferably substituted) phenazine compound, said process comprising at least one of the following steps (a), (b) and (c): (a) treatment of the electrolyte solution to be regenerated in order to convert organic degradation compounds contained therein to a (substituted) phenazine compound; (b) removal of precipitated material from the electrolyte solution and subsequent modification of the precipitated organic degradation compounds to obtain a (substituted) phenazine compound; and (c) separation of redox active compounds other than (substituted) phenazine compounds in particular inorganic electrolytes, from an electrolyte solution containing (substituted) phenazine compounds, and/or separation of (substituted) phenazine compounds from a solution containing redox active compounds other than (substituted) phenazine compounds.

The present invention provides a process for the regeneration of an electrolyte solution of a redox-flow battery containing at least one (preferably substituted) phenazine compound, said process comprising at least one of the following steps (a), (b) and (c): (a) treatment of the electrolyte solution to be regenerated in order to convert organic degradation compounds contained therein to a (substituted) phenazine compound; (b) removal of precipitated material from the electrolyte solution and subsequent modification of the precipitated organic degradation compounds to obtain a (substituted) phenazine compound; and (c) separation of redox active compounds other than (substituted) phenazine compounds in particular inorganic electrolytes, from an electrolyte solution containing (substituted) phenazine compounds, and/or separation of (substituted) phenazine compounds from a solution containing redox active compounds other than (substituted) phenazine compounds.

The present invention discloses a method for rapidly preparing a Prussian blue analogue with a monoclinic crystal structure. The Prussian blue analogue with a monoclinic crystal structure has a chemical formula of Na.sub.xM[Fe(CN).sub.6].sub.y.Math.zH.sub.2O, where M=Mn or Fe, 1.5 <<2, and 0.5<y<1. In this method, a mixture of sodium ferrocyanide and sodium chloride is adopted as a solution A, and a solution of manganese salt or iron salt in water is adopted as a solution B; the solutions A and B are continuously and rapidly mixed by a micromixer, and the precipitation reaction is conducted to obtain a nano-precursor slurry; and the nano-precursor slurry is aged at 80 C. to 160 C. for 3 min to 2 h to obtain a Prussian blue analogue with a monoclinic crystal structure that has a particle diameter of 200 nm to 2,000 nm.

The present invention discloses a method for rapidly preparing a Prussian blue analogue with a monoclinic crystal structure. The Prussian blue analogue with a monoclinic crystal structure has a chemical formula of Na.sub.xM[Fe(CN).sub.6].sub.y.Math.zH.sub.2O, where M=Mn or Fe, 1.5 <<2, and 0.5<y<1. In this method, a mixture of sodium ferrocyanide and sodium chloride is adopted as a solution A, and a solution of manganese salt or iron salt in water is adopted as a solution B; the solutions A and B are continuously and rapidly mixed by a micromixer, and the precipitation reaction is conducted to obtain a nano-precursor slurry; and the nano-precursor slurry is aged at 80 C. to 160 C. for 3 min to 2 h to obtain a Prussian blue analogue with a monoclinic crystal structure that has a particle diameter of 200 nm to 2,000 nm.

Disclosed herein is a class of co-ordination framework materials having various useful properties. The co-ordination frameworks comprise complexes of M.sub.2[M(CN).sub.6] or A.sub.x(M.sub.2[M(CN).sub.6]), wherein M is selected from V, Cr, Mn, Fe, Co, Ni, Cu, Ag, Au, Zn, Ru, Rh, Pd and Pt; M is selected from Fe and Ru; A (when present) is located in the pores of the framework and is selected from Li.sup.+, Na.sup.+, K.sup.+, Be.sup.2+, Mg.sup.2+ and Ca.sup.2+; and x (when present) is 0<x8. Also disclosed are methods of making said materials and various uses of said materials.

The present invention relates to a method of producing a sodium iron(II)-hexacyanoferrate(II) (Na.sub.2-xFe[Fe(CN).sub.6].mH.sub.2O), where x is <0.4) material commonly referred to as Prussian White. The method comprises the steps of acid decomposition of Na.sub.4Fe(CN).sub.6.10H.sub.2O to a powder of Na.sub.2-xFe[Fe(CN).sub.6].mH.sub.2O, drying and enriching the sodium content in the Na.sub.2-xFe[Fe(CN).sub.6].mH.sub.2O powder by mixing the powder with a saturated or supersaturated solution of a reducing agent containing sodium in dry solvent under an inert gas. The steps of acid decomposition and enriching the sodium content are performed under non-hydrothermal conditions.