Transition metal cyanide coordination compounds having multiple reactions
A system, method, and articles of manufacture for a surface-modified transition metal cyanide coordination compound (TMCCC) composition, an improved electrode including the composition, and a manufacturing method for the composition according to Formula III—An electrochemical cell including a system having an anode, a cathode, and an electrolyte wherein the anode includes a material, including the material including at least one composition represented by Formula III: A x Mn y [Mn(CN) (6) ] z (Vac) (1-z) .n(H 2 O)m(Che) wherein, in Formula III, A includes one or more alkali metals including Na; and wherein 0<j≤4, 0≤k≤0.1, 1.2<x≤4, 0<y≤1, 0.8<z≤1, 0<n≤4; 0≤m≤0.2 and wherein x+2y−4z=0.
1. An electrochemical cell including a system having an anode, a cathode, and an electrolyte wherein the anode includes a material, comprising:
the material including at least one composition represented by Formula III:
A x Mn y [Mn(CN) (6) ] z (Vac) (1-z) .n (H 2 O) m (Che) (Formula III)
wherein, in Formula III, A includes one or more alkali metals including Na; and
wherein 0<j≤4, 0≤k≤0.1, 1.2≤x≤4, 0<y≤1, 0.8<z≤1, 0<n≤4; 0≤m≤0.2 and
wherein x+2y−4z=0; and
wherein said anode includes a concentration of A metals, said concentration of A metals including a first concentration of A metals x1, x1≥1.2;
wherein Formula III includes one or more Mn(CN) 6 complexes each including an Mn atom; and wherein m is an average valence of said Mn atoms found in said one or more Mn(CN) 6 complexes; and wherein (Vac) identifies a Mn(CN) 6 vacancy, and wherein each particular Mn(CN) 6 complex includes said Mn atom bonded to a plurality of cyanide groups; and
wherein (Che) identifies a chelating group;
wherein an electrochemical charging of the system is configured to reduce one or more hexacyanomanganate groups from a discharged state of Mn II (CN) 6 to a charged state of Mn I (CN) 6 ,
and wherein said electrochemical charging proceeds by a plurality of electrochemical charging reactions, including a first electrochemical charging reaction configured to increase said concentration of A metals to a second concentration of A metals x2, where x2>x1, followed by a second electrochemical charging reaction configured to increase said concentration of A metals to a third concentration of A metals x3, where x3>x2.
2. The electrochemical cell of claim 1 wherein said first and said second electrochemical charging reactions each include reversible electrochemical charging reactions.
3. The electrochemical cell of claim 2 wherein the anode includes a monoclinic phase prior to an initiation of said electrochemical charging reactions and wherein the anode undergoes, during said first electrochemical charging reaction, a first anode reaction that includes a change in phase from said monoclinic phase to a cubic phase.
4. The electrochemical cell of claim 3 wherein the anode includes a cubic phase after said first electrochemical charging reaction and wherein the anode undergoes, during said second electrochemical charging reaction, a second anode reaction that includes a change in phase from said cubic phase to a tetragonal phase.
5. The electrochemical cell of claim 2 wherein the anode includes a cubic phase prior to an initiation of said second electrochemical charging reaction and wherein the anode undergoes, during said second electrochemical charging reaction, a second anode reaction that includes a change in phase from said cubic phase to a tetragonal phase.
6. The electrochemical cell of claim 2 in which said anode undergoes a change in phase from a cubic phase to a tetragonal phase during said second reaction.
7. The electrochemical cell of claim 2 in which a discharging process of the system is configured to produce an oxidation of hexacyanomanganate groups from a charged state of Mn I (CN) 6 to a discharged state of Mn II (CN) 6 .
8. The electrochemical cell of claim 2 wherein the anode includes a capacity and wherein at least 90% of said capacity is achieved at a potential less than 1.9 V vs. Na + /Na 0 .
9. The electrochemical cell of claim 2 wherein the anode includes a capacity and wherein at least 90% of said capacity is achieved in a range of potentials less than 0.25 V.
10. The electrochemical cell of claim 1 wherein x2 is about equal to 2.0.
11. A method for operating an electrochemical cell having a system, the system including an anode, a cathode, and an electrolyte wherein the anode includes a material having at least one composition represented by Formula III:
A x Mn y [Mn(CN) (6) ] z (Vac) (1-z) .n (H 2 O) m (Che) (Formula III),
comprising:
reducing one or more hexacyanomanganate groups of the material from a discharged state of Mn II (CN) 6 to a charged state of Mn I (CN) 6 , using a first electrochemical charging reaction followed by a second electrochemical charging reaction, with said first electrochemical charging reaction increasing a concentration of A metals from a first concentration of A metals x1, x1≥1.2 to a second concentration of A metals x2 with x2>x1, and with said second electrochemical charging reaction increasing said concentration of A metals to a third concentration of A metals x3, where x3>x2.
12. The method of claim 11 wherein said first and said second electrochemical charging reactions each include reversible electrochemical charging reactions.
13. The method of claim 12 wherein the anode includes a monoclinic phase prior to an initiation of said electrochemical charging reactions and wherein the anode undergoes, during said first electrochemical charging reaction, a first anode reaction that includes a change in phase from said monoclinic phase to a cubic phase.
14. The method of claim 13 wherein the anode includes a cubic phase after said first electrochemical charging reaction and wherein the anode undergoes, during said second electrochemical charging reaction, a second anode reaction that includes a change in phase from said cubic phase to a tetragonal phase.
15. The method of claim 12 wherein the anode includes a cubic phase prior to an initiation of said second electrochemical charging reaction and wherein the anode undergoes, during said second electrochemical charging reaction, a second anode reaction that includes a change in phase from said cubic phase to a tetragonal phase.
16. The method of claim 12 in which said anode undergoes a change in phase from a cubic phase to a tetragonal phase during said second reaction.
17. The method of claim 12 in which a discharging process of the system is configured to produce an oxidation of hexacyanomanganate groups from a charged state of Mn I (CN) 6 to a discharged state of Mn II (CN) 6 .
18. The method of claim 12 wherein the anode includes a capacity and wherein at least 90% of said capacity is achieved at a potential less than 1.9 V vs. Na + /Na 0 .
19. The method of claim 12 wherein the anode includes a capacity and wherein at least 90% of said capacity is achieved in a range of potentials less than 0.25 V.
20. The method of claim 11 wherein x2 is about equal to 2.0.