Zinc electrodes for batteries
An article having a continuous network of zinc and a continuous network of void space interpenetrating the zinc network. The zinc network is a fused, monolithic structure. A method of: providing an emulsion having a zinc powder and a liquid phase; drying the emulsion to form a sponge; annealing and/or sintering the sponge to form an annealed and/or sintered sponge; heating the annealed and/or sintered sponge in an oxidizing atmosphere to form an oxidized sponge having zinc oxide on the surface of the oxidized sponge; and electrochemically reducing the zinc oxide to form a zinc metal sponge.
1. An electrochemical cell comprising:
an anode current collector;
an anode in electrical contact with the anode current collector;
wherein the anode is made by a method comprising:
providing a mixture comprising a metallic zinc powder and a liquid phase emulsion;
drying the mixture to form a sponge;
annealing and/or sintering the sponge in an inert atmosphere or under vacuum at a temperature below the melting point of zinc to form an annealed sponge having a metallic zinc surface; and
heating the annealed sponge in an oxidizing atmosphere at a temperature above the melting point of zinc to form an oxidized sponge comprising a zinc oxide shell on the surface of the oxidized sponge;
wherein the anode comprises:
a continuous network comprising metallic zinc;
a continuous network of void space interpenetrating the zinc network; and
metallic zinc bridges connecting metallic zinc particle cores;
an electrolyte filling the void space;
a cathode current collector;
a cathode comprising nickel, nickel hydroxide, or nickel oxyhydroxide in electrical contact with the cathode current collector; and
a separator between the anode and the cathode.
2. The electrochemical cell of claim 1 , wherein the surface of the zinc network comprises one or more of zinc oxide and zinc oxide oxyhydroxides.
3. The electrochemical cell of claim 1 , wherein the zinc powder or liquid phase comprises an additive that suppresses gas evolution and corrosion of the sponge.
4. The electrochemical cell of claim 3 , wherein the additive comprises bismuth and indium.
5. The electrochemical cell of claim 1 , wherein the method of making the anode further comprises:
heating the oxidized sponge in an inert atmosphere at a temperature above the melting point of the zinc.
6. The electrochemical cell of claim 1 , wherein the surface of the anode comprises calcium hydroxide.
7. The electrochemical cell of claim 1 , wherein the electrolyte comprises potassium hydroxide and lithium hydroxide.
8. An electrochemical cell comprising:
an anode current collector;
an anode in electrical contact with the anode current collector;
wherein the anode is made by a method comprising:
providing a mixture comprising a metallic zinc powder and a liquid phase emulsion;
drying the mixture to form a sponge;
annealing and/or sintering the sponge in an inert atmosphere or under vacuum at a temperature below the melting point of zinc to form an annealed sponge having a metallic zinc surface;
heating the annealed sponge in an oxidizing atmosphere at a temperature above the melting point of zinc to form an oxidized sponge comprising a zinc oxide shell on the surface of the oxidized sponge; and
electrochemically reducing the zinc oxide to form a zinc metal sponge;
wherein the anode comprises:
less than 5 wt. % of zinc oxide;
a continuous network comprising metallic zinc;
a continuous network of void space interpenetrating the zinc network; and
metallic zinc bridges connecting metallic zinc particle cores;
an electrolyte filling the void space;
a cathode current collector;
a cathode comprising nickel, nickel hydroxide, or nickel oxyhydroxide in electrical contact with the cathode current collector; and
a separator between the anode and the cathode.