Secondary battery electrode, and method for producing same
A method for producing a secondary battery electrode, according to the present invention, comprises: a slicing step for producing an active material film by slicing an active material bulk; and a binding step for combining a current collector and the active material film. A method for producing a secondary battery electrode according to the present invention produces an active material film by slicing an active material bulk, which is a free-standing molded body or pellet, thus allowing binder-free active material film to be produced, and as no actual restrictions exist for the thickness of the active material film, thick active material film can be produced, and thus electrodes having high-loading and high composite density can be produced.
1. A method of producing an electrode for a lithium secondary battery, the method comprising:
a cutting step of slicing an active material bulk to produce an active material film; and
a binding step of integrating a current collector and the active material film,
wherein the lithium secondary battery has a structure in which the active material film has open pore channels on a cross section in a thickness direction, and the open pore channels penetrate the active material film, and
wherein the active material film has an apparent porosity of 10 to 45%,
wherein an electrode active material in the active material bulk has an orientation that is substantially parallel to the thickness direction of the active material film, and the orientation of the electrode active material in the active material film is controlled by a cutting direction in the cutting step.
2. The method of producing an electrode for a secondary battery of claim 1 , further comprising:
a bulk production step of using a raw material including a particulate electrode active material to produce the active material bulk, before the slicing step.
3. The method of producing an electrode for a secondary battery of claim 2 , wherein the bulk production step includes: a molding step of compression-molding the raw material to produce a molded body; or the molding step and a sintering step of heat-treating the molded body produced in the molding step to produce a sintered body.
4. The method of producing an electrode for a secondary battery of claim 3 , wherein the raw material further includes one or more additives selected from the group comprising binders, conductive materials, carbon precursors, and pore forming agents.
5. The method of producing an electrode for a secondary battery of claim 1 , wherein the binding step includes:
forming an adhesive layer on at least one surface of a surface of the current collector and a surface of the active material film; and
layering the current collector and the active material film so as to be in contact with each other, with the adhesive layer interposed therebetween.
6. The method of producing an electrode for a secondary battery of claim 1 , wherein the binding step includes:
forming a metal film on one surface of the active material film.
7. The method of producing an electrode for a secondary battery of claim 2 , wherein the active material contains natural graphite, artificial graphite, or a mixture thereof.
8. The method of producing an electrode for a secondary battery of claim 2 , wherein the bulk production step includes press-molding the raw material including a particulate electrode active material and a carbon precursor to produce the molded body; and heat-treating the molded body to pyrolyze the carbon precursor into carbon.
9. The method of producing an electrode for a secondary battery of claim 5 , wherein the adhesive layer includes a conductive material.
10. The method of producing an electrode for a secondary battery of claim 9 , wherein the conductive material of the adhesive layer includes carbon black, Ketjen black, carbon nanofibers, and carbon nanotubes.
11. The method of producing an electrode for a secondary battery of claim 2 , wherein the bulk production step includes press-molding at least one or more of the raw materials including an electrode active material core, a material of a carbon precursor shell, or composite particles having a core-shell structure as the particulate electrode active material to produce a molded body; and heat-treating the molded body to pyrolyze a carbon precursor of the shell into carbon.