Flow battery electrolyte compositions containing a chelating agent and a metal plating enhancer
An aqueous electrolyte for a metal-halogen flow battery includes an electrolyte that includes zinc bromide, a chelating agent, and a metal plating enhancer. The metal plating enhancer may include Bi, Pb, Te, Se, and/or Tl, salts thereof, or any combination thereof.
1. A flow battery system, comprising: a stack of flow battery cells that do not contain a separator in reaction zones formed between anode and cathode electrodes of each flow battery cell;
a reservoir connected to the reaction zones of the stack; and
a liquid electrolyte disposed in the reservoir, the electrolyte comprising: zinc bromide;
a chelating agent comprising N-{2-[Bis(carboxymethyl)amino]ethyl}-N-(2-hydroxyethyl)glycine (HEDTA);
at least one metal plating enhancer comprising a bismuth salt; and
a bromine sequestering agent;
wherein the electrolyte further comprises both an anti-dendrite agent and an anti-corrosion agent;
wherein the anti-dendrite agent is bisphenol A alkoxylate (BPA).
2. The system of claim 1 , wherein the anti-corrosion agent is the poly(oxy ether), and wherein the poly(oxy ether) has a molecular weight of at least 4000 Daltons.
3. The system of claim 1 , wherein the electrolyte further comprises zinc chloride.
4. The system of claim 1 , wherein:
the anti-corrosion agent comprises poly(ethylene oxide)(PEG) having a molecular weight of at least 4000 Daltons.
5. The system of claim 1 , wherein the sequestering agent is at least one of a morpholinium, pyrrolidinium, imidazolium, picolinium, pyridinium, or ammonium bromide salt (QBr).
6. The system of claim 5 , wherein the sequestering agent is at least one of 1-dodecyl-1-methylmorpholinium bromide, 1-dodecyl-1-methylpyrrolidinium bromide, 1-dodecylpyridinium bromide, dodecyltrimethylammonium bromide, benzyldodecyldimethylammonium bromide, tetrabutylammonium bromide, 1-ethyl-1-methylpyrrolidinium bromide (MEP), and 1-ethyl-1-methyl-morpholinium bromide (MEM).
7. The system of claim 1 , wherein the metal plating enhancer further comprises a lead salt.
8. The system of any of claim 7 , wherein the lead salt comprises PbCl 2 , PbBr 2 , or a combination of PbCl 2 and PbBr 2 .
9. The system of claim 8 , wherein the bismuth salt is at least one of bismuth oxide, bismuth chloride, and bismuth citrate.