Electrolytic doping of non-electrolyte layers in printed batteries
An electrical or electrochemical cell, c a cathode layer, an electrolyte layer, and an anode layer is disclosed. The cathode layer includes a first material providing a cathodic electric transport, charge storage or redox function. The electrolyte layer includes a polymer, a first electrolyte salt, and/or an ionic liquid. The anode layer includes a second material providing an anodic electric transport, charge storage or redox function. At least one of the cathode and anode layers includes the ionic liquid, a second electrolyte salt, and/or a transport-enhancing additive.
1. A positive electrode ink for printing a positive electrode layer of an electrochemical cell over a positive current collector of the electrochemical cell, the positive electrode ink comprising:
a positive active material, comprising a metal oxide;
a polymer binder, comprising at least one of polyvinylidene fluoride, a copolymer of polyvinylidene fluoride, a polyaniline, a polyether, a polyethylene oxide, a polyimide, a polyacrylate, a polyacrylic copolymer, a polyester, a polyester copolymer, or a polyvinylidene chloride;
a conductive additive, comprising at least one of graphite, acetylene black, carbon nanotubes, or graphene; and
a doping solution, comprising an ionic liquid and an electrolyte salt,
the ionic liquid, comprising at least one type of cations selected from the group consisting of imidazolium, pyrrolidinium, tetraalkyl amine, and ammonium, and also comprising at least one type of anions selected from the group consisting of trifluoromethane-sulfonate (triflate), bis((trifluoromethyl)sulfonyl)imide, triflate sulfimide, hexafluorophosphate, and tetrafluoroborate,
the electrolyte salt, comprising at least one type of cations selected from the group consisting of zinc cations, aluminum cations, magnesium cations, and yttrium cations and also comprising at least one type of anions selected from the group consisting of chloride, tetrafluoroborate (BF 4 − ), trifluoroacetate (CF 3 CO 2 − )trifluoromethanesulfonate (CF 3 SO 3 − ), hexafluorophosphate (PF 6 − ), bis(trifluoromethylsulfonyl) amide (NTf 2 − ), and bis(fluorosulfonyl)imide (N(SO 2 F) 2 ) − .
2. The positive electrode ink of claim 1 , wherein the ionic liquid comprises are imidazolium salt or a pyrrolidinium salt.
3. The positive electrode ink of claim 1 , wherein the ionic liquid comprises 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.
4. The positive electrode ink of claim 1 , wherein the electrolyte salt comprises zinc(II) bis(trifluoromethanesulfonyl)imide.
5. The positive electrode ink of claim 1 , wherein the polymer binder comprises poly(vinylidene fluoride-co-hexafluoropropene).
6. The positive electrode ink of claim 1 , further comprising a solvent.
7. The positive electrode ink of claim 6 , wherein the solvent has a high boiling point of greater than 150° C. at 1 atm.
8. The positive electrode ink of claim 1 , wherein the metal oxide of the positive active material comprises one of manganese oxide, vanadium oxide, metal cobalt oxide, or a ternary oxide.
9. The positive electrode ink of claim 1 , wherein the metal oxide is manganese oxide.
10. The positive electrode ink of claim 1 , wherein the doping solution is a separate ink part from the positive active material, the polymer binder, and the conductive additive.
11. The positive electrode ink of claim 1 , wherein the conductive additive comprises graphite and acetylene black.
12. The positive electrode ink of claim 1 , wherein the doping solution is mixed with the positive active material, the polymer binder, and the conductive additive.
13. The positive electrode ink of claim 1 , wherein the ionic liquid or the electrolyte salt is at a saturation concentration in the positive electrode ink.
14. The positive electrode ink of claim 1 , wherein the positive electrode ink is configured for stencil printing.
15. The positive electrode ink of claim 1 , further comprises a pH modifier, selected from the group consisting of a low pH buffer and an acidic additive.
16. The positive electrode ink of claim 6 , wherein the solvent is n-methylpyrolidone (NMP).
17. The positive electrode ink of claim 6 , wherein the solvent has a high boiling point of greater than 200° C. at 1 atm.
18. The positive electrode ink of claim 1 , wherein:
the ionic liquid comprises 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide;
the electrolyte salt comprises zinc(II) bis(trifluoromethanesulfonyl)imide; and
the polymer binder comprises poly(vinylidene fluoride-co-hexafluoropropene).
19. The positive electrode ink of claim 18 , wherein the metal oxide is manganese oxide.
20. The positive electrode ink of claim 15 , wherein the pH modifier comprises the acidic additive selected from the group consisting of a carboxylic acid and a fatty acid.