Stabilization of battery electrodes using prussian blue analogue coatings
View Patent ↗An electrochemical apparatus (e.g. a battery (cell)) including an aqueous electrolyte and one or two electrodes (e.g., an anode and/or a cathode), one or both of which includes a Prussian Blue analogue (PBA) material of the general chemical formula A x P[R(CN) 6-j L j ] z .nH 2 O, where: A is a cation; P is a metal cation; R is a transition metal cation; L is a ligand that may be substituted in the place of a CN − ligand; 0≦x≦2; 0≦z≦1; and 0≦n≦5, one or both electrodes including a PBA coating to decrease capacity loss.
1. An electrochemical apparatus, comprising:
an aqueous electrolyte having a plurality of ions;
a first electrode disposed in said aqueous electrolyte, said first electrode including a first Prussian Blue analogue material having a general chemical formula A x P y [R(CN) 6-j L j ] z .nH 2 O, where: A is a cation, P is a metal cation, R is a transition metal cation, and L is a ligand substitutable in the place of a CN − ligand, and 0≦j≦6, 0≦x≦2, 0 L<y≦4, 0<z≦1, and 0≦n≦5 wherein said first Prussian Blue analogue material has a first specific chemical formula conforming to said general chemical formula including a first particular cation P 1 and a first particular cation R 1 and wherein said first Prussian Blue analogue material has a first rate of electrochemical capacity loss when disposed in said aqueous electrolyte; and
a first conformal layer disposed on said first Prussian Blue analogue material configured to form a protective barrier between said first Prussian Blue analogue material and said aqueous electrolyte, said first conformal layer conductive to said plurality of ions;
wherein said first electrode with said first conformal layer has a second rate of electrochemical loss less than said first rate of electrochemical capacity loss when said first electrode is disposed in said aqueous electrolyte.
2. The electrochemical apparatus of claim 1 wherein said first conformal layer includes a second Prussian Blue analogue material having said general chemical formula and a second specific chemical formula different from said first specific chemical formula.
3. The electrochemical apparatus of claim 2 wherein said first Prussian Blue analogue material includes copper hexacyanoferrate.
4. The electrochemical apparatus of claim 2 wherein said first Prussian Blue analogue material includes manganese hexacyanomanganate.
5. The electrochemical apparatus of claim 2 wherein said second specific chemical formula includes ferric ferriccyanide.
6. The electrochemical apparatus of claim 3 wherein said second specific chemical formula includes ferric ferriccyanide.
7. The electrochemical apparatus of claim 2 wherein said first conformal layer includes a plurality of nanoparticles having an average size less than 1 micron.
8. The electrochemical apparatus of claim 2 wherein said first conformal layer has a first thickness less than 1 micron.
9. The electrochemical apparatus of claim 2 wherein said first conformal layer has a first thickness less than 10 microns.
10. The electrochemical apparatus of claim 2 wherein said plurality of ions includes said first particular cation P 1 .
11. The electrochemical apparatus of claim 10 wherein said second specific chemical formula includes a second particular cation P 2 , said second particular cation P 2 different from said first particular cation P 1 , and wherein said plurality of ions includes said second particular cation P 2 .
12. The electrochemical apparatus of claim 2 wherein said second specific chemical formula includes a second particular cation P 2 and wherein said plurality of ions includes said second particular cation P 2 .
13. The electrochemical apparatus of claim 12 wherein said second particular cation P 2 is different from said first particular cation P 1 .
14. The electrochemical apparatus of claim 1 wherein said first electrode is configured as a cathode, and further comprising a second electrode disposed in said aqueous electrolyte configured as an anode including an elemental metal having said first particular cation P 1 .
15. The electrochemical apparatus of claim 1 wherein said first electrode is configured as a cathode, and further comprising a second electrode disposed in said aqueous electrolyte configured as an anode including an alloy having said first cation P.
16. The electrochemical apparatus of claim 2 wherein said first Prussian Blue analogue material includes a plurality of individual particles, each individual particle having an outside surface and wherein said first conformal layer is disposed on said outside surfaces.
17. The electrochemical apparatus of claim 16 wherein said first Prussian Blue analogue material includes a first electrochemical reaction potential and wherein said second Prussian Blue analogue material includes a second electrochemical reaction potential lower than said first electrochemical reaction potential.
18. The electrochemical apparatus of claim 16 wherein said first Prussian Blue analogue material includes a first electrochemical reaction potential and wherein said second Prussian Blue analogue material includes a second electrochemical reaction potential equal to said first electrochemical reaction potential.
19. The electrochemical apparatus of claim 16 wherein said first Prussian Blue analogue material includes a first electrochemical reaction potential and wherein said second Prussian Blue analogue material includes a second electrochemical reaction potential higher than said first electrochemical reaction potential.
20. The electrochemical apparatus of claim 19 wherein said specific chemical formulae are configured such that an electrochemical cycling of said first electrode in said aqueous electrolyte that includes both an oxidation and a reduction of said first Prussian Blue analogue material excludes an oxidation of said second Prussian Blue analogue material.
21. The electrochemical apparatus of claim 17 wherein said specific chemical formulae are configured such that an electrochemical cycling of said first electrode in said aqueous electrolyte that includes both an oxidation and a reduction of said first Prussian Blue analogue material excludes a reduction of said second Prussian Blue analogue material.
22. The electrochemical apparatus of claim 16 wherein said specific chemical formulae are configured such that an electrochemical cycling of said first electrode in said aqueous electrolyte that includes both an oxidation and a reduction of said first Prussian Blue analogue material includes both an oxidation and a reduction of said second Prussian Blue analogue material.
23. The electrochemical apparatus of claim 1 wherein said general chemical formula includes:
A is one or more cations selected from the group consisting of Na + , K + , Li + , NH 4 + , Mg2 + , or Ca2 + and combinations thereof;
P is one or more metal cations selected from the group consisting of 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;
R is one or more transition metal cations selected from the group consisting of V 2+ , V 3+ , Cr 2+ , Cr 3+ , 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+ , or Pt 3+ and combinations thereof; and
L is one or more ligands that may be substituted in the place of a CN − ligand selected from the group consisting of CO (carbonyl), NO (nitrosyl), or Cl − and combinations thereof.