Electrolyte additives for zinc metal electrodes
Zinc metal negative electrodes and aqueous electrolytes can be used in a rechargeable battery. The electrolyte can include zinc sulfate dissolved in water with a pH in the range of 0-7, and at least one additive for increasing ionic conductivity of the electrolyte, and/or buffering the pH of the electrolyte, and/or controlling morphology of a stripped/plated surface of the negative electrode. The electrolyte can decrease the likelihood of internal short circuits caused by volumetric expansion of the negative electrode and morphology changes after repeated cycling and penetration of zinc metal through a separator to a positive electrode.
1 . A rechargeable zinc battery in a stacked configuration, comprising:
a positive electrode;
a negative electrode comprising zinc; and
an electrolyte for transferring Zn 2+ ions between the negative electrode and the positive electrode, the electrolyte comprising:
zinc sulfate dissolved in water with a pH in the range of 0-7; and
at least one first additive comprising boric acid for buffering the pH of the electrolyte; and
at least one second additive comprising one or more of ethylene glycol, nicotinamide, sodium dodecyl sulphate, and ethylvanillin for smoothing a stripped/plated surface of the negative electrode;
wherein, during normal operation, zinc ions are products or reactants of electrochemical reactions at each electrode, wherein the electrochemical reactions account for the majority of charge transferred at each electrode, and wherein the rechargeable zinc battery is selected from the group consisting of a zinc-ion battery, a zinc hybrid supercapacitor, a zinc-bromide battery, a zinc-iodide battery, a zinc-iron redox flow battery, and a zinc-cerium redox flow battery.
2 . The apparatus of claim 1 , wherein the at least one first additive is present in the electrolyte in a range from about 0.005 M to about 6 M.
3 . The apparatus of claim 1 , wherein the at least one second additive is present in the electrolyte in a range from about 10 ppm to about 50 percent.
4 . The apparatus of claim 1 , wherein the zinc sulfate is dissolved so that the Zn 2+ ions are present in the electrolyte in a range from about 0.05 M to about 4 M.
5 . The apparatus of claim 1 , wherein the pH of the electrolyte is between about 4 and about 6.
6 . The apparatus of claim 1 , wherein the negative electrode is formed substantially of any one of a zinc metal and a zinc alloy.
7 . The apparatus of claim 1 , wherein the negative electrode comprises a current collector, wherein the current collector is formed substantially of a material selected from the group consisting of carbon, boron, lead, vanadium, chromium, manganese, iron, cobalt, nickel, cadmium, tungsten, bismuth, tin, indium, antimony, copper, titanium, zinc metal, and any combination thereof.
8 . The apparatus of claim 1 , wherein the rechargeable battery is an aqueous rechargeable battery.
9 . An aqueous electrolyte configured for use with a rechargeable zinc battery in a stacked configuration comprising a positive electrode, a negative electrode, the aqueous electrolyte being disposed therebetween, the aqueous electrolyte comprising:
zinc sulfate dissolved in water with a pH in the range of 0-7; and
at least one first additive comprising boric acid for buffering the pH of the electrolyte; and
at least one second additive comprising one or more of ethylene glycol, nicotinamide, sodium dodecyl sulphate, and ethylvanillin for smoothing a stripped/plated surface of a negative electrode of the rechargeable battery;
wherein, during normal operation, zinc ions are products or reactants of electrochemical reactions at each electrode of the rechargeable battery, wherein the electrochemical reactions account for the majority of charge transferred at each electrode, and wherein the rechargeable zinc battery is selected from the group consisting of a zinc-ion battery, a zinc hybrid supercapacitor, a zinc-bromide battery, a zinc-iodide battery, a zinc-iron redox flow battery, and a zinc-cerium redox flow battery.
10 . The electrolyte of claim 9 , wherein the first additive is present in the electrolyte in a range from about 0.005 M to about 6 M.
11 . The electrolyte of claim 9 , wherein the second additive is present in the electrolyte in a range from about 10 ppm to about 50 percent.
12 . The electrolyte of claim 9 , wherein the zinc sulfate is dissolved so that the Zn 2+ ions are present in the electrolyte in a range from about 0.05 M to about 4 M.
13 . The electrolyte of claim 9 , wherein the pH of the electrolyte is between about 4 and about 6.
14 . The electrolyte of claim 9 , wherein the second additive is a brightener used in electroplating processes.
15 . The rechargeable battery of claim 1 , wherein the second additive is a brightener used in electroplating processes.