Partially and fully surface-enabled alkali metal ion-exchanging energy storage devices
A surface-enabled, metal ion-exchanging battery device comprising a cathode, an anode, a porous separator, and a metal ion-containing electrolyte, wherein the metal ion is selected from (A) non-Li alkali metals; (B) alkaline-earth metals; (C) transition metals; (D) other metals such as aluminum (Al); or (E) a combination thereof; and wherein at least one of the electrodes contains therein a metal ion source prior to the first charge or discharge cycle of the device and at least the cathode comprises a functional material or nanostructured material having a metal ion-capturing functional group or metal ion-storing surface in direct contact with said electrolyte, and wherein the operation of the battery device does not involve the introduction of oxygen from outside the device and does not involve the formation of a metal oxide, metal sulfide, metal selenide, metal telluride, metal hydroxide, or metal-halogen compound. This energy storage device has a power density significantly higher than that of a lithium-ion battery and an energy density dramatically higher than that of a supercapacitor.
1. A partially or fully surface-enabled, metal ion-exchanging battery device comprising (a) a positive electrode (cathode), (b) a negative electrode (anode), (c) a porous separator disposed between said cathode and said anode, and (d) an electrolyte in physical contact with said cathode and said anode, wherein said electrolyte contains an alkali metal ion that is exchanged between said cathode and said anode during an operation of said battery device and said alkali metal is selected from sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), or a combination thereof; wherein at least one of said cathode and said anode contains therein a source of said alkali metal ion prior to a first charge or a first discharge cycle of the battery device and at least the cathode comprises nano graphene having a surface-borne metal ion-capturing functional group or comprises a nano-structured material having a metal ion-storing surface in direct contact with said electrolyte to reversibly capture or store said alkali metal ion during charge-discharge operations of said battery, wherein the nano graphene is selected from a single-layer graphene sheet or a multi-layer graphene platelet, wherein said nano graphene is surrounded by interconnected pores having a size from 2 to 50 nm, and wherein said operations of said battery device does not involve the introduction of oxygen from outside said device, does not involve solid state diffusion of said alkali metal ions in and out of bulk of said cathode, and does not involve the formation of a metal oxide, metal sulfide, metal selenide, metal telluride, metal hydroxide, or metal-halogen compound; wherein at least one of the cathode and the anode has a functional material having a functional group that reversibly reacts with a metal ion, forms a redox pair with a metal ion, or forms a chemical complex with a metal ion.
2. The battery device of claim 1 , wherein both said cathode and said anode have a functional material having a functional group that reversibly reacts with a metal ion, forms a redox pair with a metal ion, or forms a chemical complex with a metal ion.
3. The battery device of claim 1 , wherein at least one of said cathode and said anode has a nano-structured functional material having a specific surface area no less than 100 m 2 /gram to store or support metal ions or atoms thereon.
4. The battery device of claim 1 , wherein both of said cathode and said anode have a nano-structured functional material having a specific surface area no less than 100 m 2 /gram to store or support metal ions or atoms thereon.
5. The battery device of claim 4 , wherein the specific surface area is no less than 500 m 2 /gram.
6. The battery device of claim 5 , wherein the specific surface area is no less than 500 m 2 /gram.
7. The battery device of claim 1 , wherein at least one of the functional materials is single-walled or multi-walled carbon nanotube.
8. The battery device of claim 1 , wherein each of the two electrodes comprises a single-walled or multi-walled carbon nanotube.
9. The battery device of claim 1 , wherein said functional materials or nano-structured material has a specific surface area of at least 500 m 2 /g.
10. The battery device of claim 1 , wherein said functional materials or nano-structured material has a specific surface area of at least 1,500 m 2 /g.
11. The battery device of claim 1 , wherein said device provides an energy density of no less than 100 Wh/kg or power density no lower than 10 Kw/kg, all based on an electrode weight.
12. The battery device of claim 1 , wherein said device provides an energy density of no less than 200 Wh/kg or power density no lower than 50 Kw/kg, all based on an electrode weight.
13. The battery device of claim 1 , wherein said device provides an energy density of no less than 300 Wh/kg or power density no less than 100 Kw/kg, all based on an electrode weight.
14. The battery device of claim 1 , wherein said positive electrode has a thickness greater than 5 μm.
15. The battery device of claim 1 , wherein said positive electrode has a thickness greater than 50 μm.
16. The battery device of claim 1 , wherein said positive electrode has a thickness greater than 100 μm.