Low vacancy Fe-substituted Mn-based prussian blue analogue
A system and method implementing and manufacturing transition metal cyanide coordination compounds (TMCCC) comprising Na, Fe, Mn, C, H, N, S, and O, wherein the TMCCC have 0-14% hexacyanometallate vacancies such as for application in electrochemical cells, including sodium ion secondary batteries.
1. A method of producing a TMCCC Formula II material, comprising the steps of:
(a) Admixing a solvent additive, a sodium salt and water to produce a first reaction mixture;
(b) Admixing an iron (III) source, a manganese (II) source and a first solvent to produce a second reaction mixture;
(c) Admixing a sodium hexacyanoferrate (II) source, a potassium hexacyanoferrate (III) source and a second solvent to produce a third reaction mixture;
(d) Contacting said second reaction mixture and said third reaction mixture to said first reaction mixture to produce a TMCCC;
(e) Admixing a buffer and said TMCCC to produce a fourth reaction mixture; and
(f) Contacting said fourth reaction mixture with a sulfur-containing reducing agent to produce a Prussian white TMCCC including the Formula II material; and
wherein said Formula II includes:
Na b1 K b2 Rb b3 Cs b4 Fr b5 Ti a1 V a2 Cr a3 Mn a4 Fe a5 CO a6 Ni a7 Cu a8 Zn a9 Ca a10 Mg a11 [R(CN) 6 ] c vac r (H 2 O) n (SO 4 ) j wherein R(CN) 6 includes a coordination complex selected from the group consisting of hexacyanoferrate, hexacyanocobaltate, hexacyanochromate, and hexacyanomanganate; wherein vac identifies an R(CN) 6 vacancy; wherein for at least one element of a set of alkali metal parameters {b1, b2}, {b1, b2}>0; wherein for each element of the set {b1, b2, b3, b4, b5} excluding non-zero elements of said set of alkali metal parameters, 0≤{b1, b2, b3, b4, b5}; wherein for each element of the set {b1, b2, b3, b4, b5} {b1, b2, b3, b4, b5}≤2; wherein b1+b2+b3+b4+b5≤2; wherein for each element of the set {a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11}, 0≤{a1, a2, a3, a4, a6, a7, a8, a9, a10, a11}≤1, a5>0; wherein at least two of {a1, a2, a3, a4, a5, a6, a7, a8, a9, a10, a11} are >0; wherein 0<c≤1; wherein 0≤r≤0.25; wherein j>0; wherein c+r=1; and wherein n≥0.
2. The method of claim 1 , wherein said solvent additive is selected from the group consisting of ethylene glycol, sorbitol, ethanolamine, succinonitrile, acetonitrile, Triethanolamine, Triethanolamine borate, 1-Aminopropan-2-ol, glycerol, 2-aminoethanethiol, 2-Mercaptoethanol, acetic anhydride, propane-1,2-diol, 1,3-Propanediol, 1,2-Butanediol, 1,4-Butanediol, 1,3-Butanediol, 2,2-Bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol, 1,3-Bis[tris(hydroxymethyl)methylamino]propane, 2-Amino-2-(hydroxymethyl)-1,3-propanediol, N,N-Bis(2-hydroxyethyl)glycine, 3-(N,N-Bis[2-hydroxyethyl]amino)-2-hydroxypropanesulfonic acid, 2-Amino-2-methyl-1,3-propanediol, 1,2-Diaminoethane, or mixtures thereof.
3. The method of claim 1 , wherein said solvent additive is selected from a nitrogen-containing heterocyclic compound, Hydroxylamine, primary amines, secondary amine, tertiary amine, alcohol, or mixtures thereof.
4. The method of claim 1 , wherein said iron (III) source is selected from Fe 2 (SO 4 ) 3 (H 2 O) k wherein k≥0, or FeSO 4 ·xH 2 O wherein x≥0, or mixtures thereof.
5. The method of claim 1 , wherein said manganese (II) source is selected from MnSO 4 ·yH 2 O wherein y≥0 or mixtures thereof.
6. The method of claim 1 , wherein said buffer is prepared from sodium hydroxide and succinic acid.
7. The method of claim 1 , wherein said sulfur-containing reducing agent is selected from the group consisting of sodium dithionite, tetraethylammonium dithionite, sodium hydroxymethanesulfinate, thiourea dioxide and N,N-dimethyl thiourea dioxide, or mixtures thereof.
8. The method of claim 1 wherein said solvents in (b) and (c) are selected from the group consisting of water, methanol, ethanol, ethylene glycol, or mixtures thereof.
9. The method of claim 1 , wherein one or more of said steps of admixing are performed at a temperature between about 20° C. and about 150° C.
10. The method of claim 1 , wherein said Prussian white in (f) includes a TMCCC comprising of Na, Fe, Mn, C, H, N, S, and O.
11. The method of claim 1 , wherein said TMCCC in (f) includes a TMCCC with monoclinic, rhombohedral, cubic crystal structure, or mixtures thereof.