Current collector for battery and secondary battery comprising the same
View Patent ↗Provided is a current collector including a laminate in which a conductive substrate and an insulator are laminated, wherein the insulator is a porous insulator formed with an open pore channel penetrating through the insulator. The current collector may be used as a current collector for an electrode of a secondary battery and stably maintain capacity of the secondary battery at the time of repeating charge and discharge cycles.
1. A sodium secondary battery comprising:
an anode containing sodium;
a cathode solution;
a sodium ion conductive solid electrolyte separating the anode and the cathode solution from each other; and
a cathode current collector immersed into the cathode solution and spaced apart from the sodium ion conductive solid electrolyte,
wherein the cathode current collector comprises: a conductive substrate and an insulator laminated on a surface of the conductive substrate;
wherein the insulator is formed of a polymer and formed with a plurality of open pore channels penetrating through the insulator, the cathode solution is filled inside the open pore channels, and a portion of the surface of the conductive substrate is exposed to and directly contacts with the cathode solution by the open pore channels, and
wherein the cathode solution contains: a metal halide, which is a halide of at least one metal selected from the group consisting of transition metals and Groups 12 to 14 metals; and a solvent dissolving the metal halide.
2. The sodium secondary battery of claim 1 , wherein the cathode solution further contains a sodium halide dissolved by the solvent.
3. The sodium secondary battery of claim 2 , wherein a charge reaction of the sodium secondary battery is carried out according to the following Reaction Formula 1, and a discharge reaction of the sodium secondary battery is carried out according to the following Reaction Formula 2,
mNaX+M→mNa+MX m (Reaction formula 1)
mNa+MX m →mNaX+M (Reaction formula 2)
(where M is the at least one metal, X is a halogen atom, and m is a natural number of 1 to 4, MX m , is the metal halide and NaX is the sodium halide).
4. The sodium secondary battery of claim 1 , wherein the cathode solution further contains at least one plating additive selected from the group consisting of a suppressor, a leveler, and an accelerator.
5. The sodium secondary battery of claim 4 , wherein the accelerator is a sulfur-containing organic compound, the suppressor is an oxygen-containing polymer compound having a weight average molecular weight (Mw) of 1000 to 20000 g/mol, and the leveler is a nitrogen-containing organic material.
6. The sodium secondary battery of claim 1 , wherein the portion of the surface of the conductive substrate A p satisfies the following Correlation Equation 1,
0.05 A s ≦ A p ≦0.8 A s (Correlation Equation 1)
(where A s is a total area of the surface on which the insulator is laminated).
7. The sodium secondary battery of claim 1 , wherein the open pore channels are arrayed to be spaced apart from one another.
8. The sodium secondary battery of claim 7 , wherein each of the open pore channels has a cross-sectional area of 0.01 to 80 mm 2 .
9. The sodium secondary battery of claim 1 , wherein the conductive substrate includes a plate shaped conductive substrate, and the insulator is laminated on a surface of the plate shaped conductive substrate.
10. The sodium secondary battery of claim 1 , wherein the insulator includes a hollow cylindrical shaped insulator, and the conductive substrate encloses an outer surface or an inner surface of the hollow cylindrical shaped insulator.
11. The sodium secondary battery of claim 1 , further comprising: a cylindrical metal housing containing the anode and the cathode solution,
wherein the conductive substrate is electrically connected to the metal housing.
12. The sodium secondary battery of claim 1 , wherein the sodium secondary battery is configured to have an operation temperature of 98° C. to 150° C.