Cosolvent electrolytes for electrochemical devices
View Patent ↗A system and method for stabilizing electrodes against dissolution and/or hydrolysis including use of cosolvents in liquid electrolyte batteries for three purposes: the extension of the calendar and cycle life time of electrodes that are partially soluble in liquid electrolytes, the purpose of limiting the rate of electrolysis of water into hydrogen and oxygen as a side reaction during battery operation, and for the purpose of cost reduction.
1. An electrochemical system, comprising:
a first electrode;
a second electrode
wherein at least one of said electrodes includes a transition metal cyanide coordination compound (TMCCC) material, said at least one electrode having a first dissolution rate R 1 in a liquid electrolyte having an H 2 O component greater than 0.50; and
electrolytic means, coupled to said electrodes, for decreasing said first dissolution rate R 1 , said electrolytic means including a total volume V having a first volume fraction V 1 consisting essentially of H 2 O, V 1 /V>0.02, V 1 /V<0.50, and a second volume fraction V 2 of an organic cosolvent with V=V 1 +V 2 , V 2 >V 1 , and
wherein said total volume V=V 1 +V 2 consists essentially of a single phase.
2. The electrochemical system of claim 1 wherein the TMCCC material includes a composition having the general chemical formula A x P y [R(CN) 6−j L j ] z .nH 2 O, wherein:
A includes one or more cations;
P includes one or more metal cations;
R includes one or more transition metal cations; and
L is a ligand substituted in the place of a CN − ligand; where
0≦x≦2;
0<y≦4;
0<z≦1;
0≦j≦6; and
0≦n≦5.
3. The electrochemical system of claim 2 wherein:
said A cations include one or more cations selected from the group consisting of Na + , K + , Li + , NH 4+ , Mg 2+ Ca 2+ and combinations thereof;
said P metal cations include one or more metal cations selected from the group consisting of Ti 3+ , Ti 4+ , V 2+ , V 3+ , Cr 2+ , Cr 3+ , Mn 2+ , Mn 3+ , Fe 2+ , Fe 3+ , Co 2+ , Co 3+ , Ni 2+ , Cu + , Cu 2+ , Zn 2+ , Al 3+ , Sn 2+ , In 3+ , or Pb 2+ and combinations thereof;
said R transition metal cations include one or more transition metal cations selected from the group consisting of V 2+ , V 3+ , Cr 2+ , Cr 3+ , Mn + , Mn 2+ , Mn 3+ , Fe 2+ , Fe 3+ , Co 2+ , Co 3+ , Ru 2+ , Ru 3+ , Os 2+ , Os 3+ , Ir 2+ , Ir 3+ , Pt 2+ , Pt 3+ , and combinations thereof; and
said L ligands include one or more ligands selected from the group consisting of CO (carbonyl), NO (nitrosyl), Cl − , and combinations thereof.
4. The electrochemical system of claim 1 wherein the total liquid volume V includes one or more cations selected from the group consisting of an alkali cation, an alkali earth cation, an ammonium cation, and combinations thereof.
5. The electrochemical system of claim 4 wherein the liquid electrolyte produces a total concentration of said plurality of cations in the total liquid volume V greater than 0.1 M.
6. The electrochemical system of claim 5 wherein said total concentration is greater than 1.4 M.
7. The electrochemical system of claim 1 wherein the total liquid volume V includes one or more organic polar aprotic solvents.
8. The electrochemical system of claim 7 wherein said one or more organic polar aprotic cosolvents include a particular cosolvent having one or more cyanide groups.
9. The electrochemical system of claim 8 wherein said particular cosolvent includes acetonitrile.
10. The electrochemical system of claim 7 wherein said one or more organic polar aprotic cosolvents include a particular cosolvent having one or more carbonate groups.
11. The electrochemical system of claim 10 wherein said particular cosolvent is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, and combinations thereof.
12. The electrochemical system of claim 1 wherein the total liquid volume V includes one or more organic polar protic solvents.
13. The electrochemical system of claim 12 wherein said one or more organic polar protic solvents include a particular solvent having one or more alcohol groups.
14. The electrochemical system of claim 13 wherein said particular solvent is selected from the group consisting of methanol, ethylene glycol, glycerol, hydroxypropionitrile, and combinations thereof.
15. The electrochemical system of claim 1 wherein V 1 /V≦30% and V 2 /V≧70%.
16. The electrochemical system of claim 15 wherein V 1 /V≦10% and V 2 /V≧90%.
17. The electrochemical system of claim 7 wherein the total liquid volume V includes both a cyanide-containing cosolvent and a carbonate-containing cosolvent.
18. The electrochemical system of claim 7 wherein said one of more organic polar aprotic cosolvents include a particular cosolvent having one or more sulfone groups.
19. The electrochemical cell of claim 18 wherein said particular cosolvent includes sulfolane.
20. The electrochemical system of claim 7 wherein the total liquid volume V includes both a cyanide-containing cosolvent and a sulfone-containing cosolvent.
21. The electrochemical system of claim 1 wherein said second volume fraction V 2 includes a first volume subfraction V 3 and a second volume subfraction volume V 4 wherein V 3 +V 4 =V 2 , wherein said first volume subfraction V 3 includes a first organic cosolvent, and wherein said second volume subfraction V 4 includes a second organic cosolvent different from said first organic cosolvent.
22. The electrochemical system of claim 21 wherein said first organic cosolvent includes MeCN, and wherein said second organic cosolvent includes a solvent selected from the group consisting essentially of sulfolane, propylene glycol monoethyl ether, hydroxypropionitrile, gamma-valerolactone, ethylene carbonate, dimethyl carbonate, propylene carbonate, and 1,3-dioxolan.
23. The electrochemical system of claim 22 wherein V 1 /V=0.05, wherein V 3 /V≧0.10, and wherein V 4 /V≦0.85.
24. A rechargeable electrochemical system having a pair of electrodes disposed within a liquid electrolyte of a total volume V having a first volume fraction V 1 consisting essentially of H 2 O wherein at least one of the electrodes includes a transition metal cyanide coordination compound (TMCCC) material having a first dissolution rate R 1 in the liquid electrolyte when the first volume fraction V 1 divided by the total volume V is greater than 0.50, the improvement comprising:
a second volume fraction V 2 of the total volume V including one or more organic cosolvents;
wherein V=V 1 +V 2 ;
wherein V 2 >V 1 ;
wherein V 1 /V>0.02;
wherein V 1 /V<0.50;
wherein the liquid electrolyte consists essentially of a single phase; and
wherein the at least one electrode includes a second dissolution rate R 2 <R 1 when V=V 1 +V 2 and V 2 >V 1 and V 1 /V>0.02 and the liquid electrolyte consists essentially of a single phase.
25. The rechargeable electrochemical system of claim 24 wherein the TMCCC material includes a composition having the general chemical formula A x P y [R(CN) 6−j L j ] z .nH 2 O, wherein:
A includes one or more cations;
P includes one or more metal cations;
R includes one or more transition metal cations; and
L is a ligand substituted in the place of a CN − ligand; where
0≦x≦2;
0<y≦4;
0<z≦1;
0≦j≦6; and
0≦n≦5.
26. The rechargeable electrochemical system of claim 25 wherein:
said A cations include one or more cations selected from the group consisting of Na + , K + , Li + , NH 4+ , Mg 2+ Ca 2+ and combinations thereof;
said P metal cations include one or more metal cations selected from the group consisting of Ti 3+ , Ti 4+ , V 2+ , V 3+ , Cr 2+ , Cr 3+ , Mn 2+ , Mn 3+ , Fe 2+ , Fe 3+ , Co 2+ , Co 3+ , Ni 2+ , Cu + , Cu 2+ , Zn 2+ , Al 3+ , Sn 2+ , In 3+ , or Pb 2+ and combinations thereof;
said R transition metal cations include one or more transition metal cations selected from the group consisting of V 2+ , V 3+ , Cr 2+ , Cr 3+ , Mn + , Mn 2+ , Mn 3+ , Fe 2+ , Fe 3+ , Co 2+ , Co 3+ , Ru 2+ , Ru 3+ , Os 2+ , Os 3+ , Ir 2+ , Ir 3+ , Pt 2+ , Pt 3+ , and combinations thereof; and
said L ligands include one or more ligands selected from the group consisting of CO (carbonyl), NO (nitrosyl), Cl − , and combinations thereof.
27. The rechargeable electrochemical system of claim 24 wherein the total liquid volume V includes one or more cations selected from the group consisting of an alkali cation, an alkali earth cation, an ammonium cation, and combinations thereof.
28. The rechargeable electrochemical system of claim 27 wherein the liquid electrolyte produces a total concentration of said plurality of cations in the total liquid volume V greater than 0.1 M.
29. The rechargeable electrochemical system of claim 28 wherein said total concentration is greater than 1.4 M.
30. The rechargeable electrochemical system of claim 24 wherein the total liquid volume V includes one or more organic polar aprotic solvents.
31. The rechargeable electrochemical system of claim 30 wherein said one or more organic polar aprotic cosolvents include a particular cosolvent having one or more cyanide groups.
32. The rechargeable electrochemical system of claim 31 wherein said particular cosolvent includes acetonitrile.
33. The rechargeable electrochemical system of claim 30 wherein said one or more organic polar aprotic cosolvents include a particular cosolvent having one or more carbonate groups.
34. The rechargeable electrochemical system of claim 33 wherein said particular cosolvent is selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, and combinations thereof.
35. The rechargeable electrochemical system of claim 24 wherein the total liquid volume V includes one or more organic polar protic solvents.
36. The rechargeable electrochemical system of claim 35 wherein said one or more organic polar protic solvents include a particular solvent having one or more alcohol groups.
37. The rechargeable electrochemical system of claim 36 wherein said particular solvent is selected from the group consisting of methanol, ethylene glycol, glycerol, hydroxypropionitrile, and combinations thereof.
38. The rechargeable electrochemical system of claim 24 wherein V 1 /V≦30% and V 2 /V≧70%.
39. The rechargeable electrochemical system of claim 38 wherein V 1 /V≦10% and V 2 /V≧90%.
40. The rechargeable electrochemical system of claim 30 wherein the total liquid volume V includes both a cyanide-containing cosolvent and a carbonate-containing cosolvent.
41. The rechargeable electrochemical system of claim 30 wherein said one of more organic polar aprotic cosolvents include a particular cosolvent having one or more sulfone groups.
42. The rechargeable electrochemical cell of claim 41 wherein said particular cosolvent includes sulfolane.
43. The rechargeable electrochemical system of claim 30 wherein the total liquid volume V includes both a cyanide-containing cosolvent and a sulfone-containing cosolvent.
44. The rechargeable electrochemical system of claim 24 wherein said second volume fraction V 2 includes a first volume subfraction V 3 and a second volume subfraction volume V 4 wherein V 3 +V 4 =V 2 , wherein said first volume subfraction V 3 includes a first organic cosolvent, and wherein said second volume subfraction V 4 includes a second organic cosolvent different from said first organic cosolvent.
45. The rechargeable electrochemical system of claim 44 wherein said first organic cosolvent includes MeCN, and wherein said second organic cosolvent includes a solvent selected from the group consisting essentially of sulfolane, propylene glycol monoethyl ether, hydroxypropionitrile, gamma-valerolactone, ethylene carbonate, dimethyl carbonate, propylene carbonate, and 1,3-dioxolan.
46. The rechargeable electrochemical system of claim 45 wherein V 1 /V=0.05, wherein V 3 /V≧0.10, and wherein V 4 /V≦0.85.