Electrode material for lithium secondary battery, method for producing the same, and lithium secondary battery including the same
An electrode material for lithium secondary battery comprises a nanoheterostructure which contains a lithium-ion conductor and an electrode active substance of which one inorganic component is a matrix, and of which the other inorganic component is three-dimensionally and periodically arranged in the matrix, and has a three-dimensional periodic structure whose average value of one unit length of a repeated structure is 1 nm to 100 nm.
1. An electrode material for lithium secondary battery comprising a nanoheterostructure which contains a lithium-ion conductor and an electrode active substance of which one inorganic component is a matrix, and of which another inorganic component is three-dimensionally and periodically arranged in the matrix, and has a three-dimensional periodic structure whose average value of one unit length of a repeated structure is 1 nm to 100 nm.
2. The electrode material for lithium secondary battery according to claim 1 , wherein the inorganic component three-dimensionally and periodically arranged in the matrix has a shape selected from the group consisting of a columnar shape, a lamellar shape, and a gyroid shape.
3. The electrode material for lithium secondary battery according to claim 1 , wherein
the lithium-ion conductor is at least one selected from the group consisting of sulfide-based lithium-ion conductors, garnet-type lithium-ion conductors, LISICON-t e lithium-ion conductors, NASICON-t e lithium-ion conductors, and perovskite-t e lithium-ion conductors.
4. The electrode material for lithium secondary battery according to claim 1 , wherein
the electrode active substance is at least one positive electrode active substance selected from the group consisting of oxide-based positive electrode active substances and olivine-type positive electrode active substances.
5. The electrode material for lithium secondary battery according to claim 1 , wherein
the electrode active substance is at least one negative electrode active substance selected from the group consisting of oxide-based negative electrode active substances, carbon-based negative electrode active substances, and metal-based negative electrode active substances.
6. A lithium secondary battery comprising the electrode material according to claim 1 .
7. A lithium secondary battery comprising the electrode material according to claim 4 as a positive electrode material.
8. A lithium secondary battery comprising the electrode material according to claim 5 as a negative electrode material.
9. A method for producing an electrode material for lithium secondary battery of which one inorganic component is a matrix, and of which another inorganic component is three-dimensionally and periodically arranged in the matrix, and has a three-dimensional periodic structure whose average value of one unit length of a repeated structure is 1 nm to 100 nm, the method comprising:
a first step of preparing a raw material solution by dissolving, in a solvent,
a block copolymer comprising at least a first polymer block component and a second polymer block component which are immiscible but linked to each other,
a first inorganic precursor which is one of a lithium-ion conductor precursor and an electrode active substance precursor, and
a second inorganic precursor which is the other of the lithium-ion conductor precursor and the electrode active substance precursor; and
a second step including
a phase-separation treatment for forming a nanophase-separated structure in which at least a first polymer phase comprising the first polymer block component with the first inorganic precursor introduced thereinto and a second polymer phase comprising the second polymer block component with the second inorganic precursor introduced thereinto are regularly arranged by self-assembly,
a conversion treatment for converting the lithium-ion conductor precursor and the electrode active substance precursor to a lithium-ion conductor and an electrode active substance, respectively, and
a removal treatment for removing the block copolymer from the nanophase-separated structure, to thereby obtain an electrode material having a nanoheterostructure comprising the lithium-ion conductor and the electrode active substance.
10. The method for producing an electrode material for lithium secondary battery according to claim 9 , wherein
a solubility parameter difference between the first inorganic precursor and the first polymer block component is 2 (cal/cm 3 ) 1/2 or less, and a solubility parameter difference between the second inorganic precursor and the second polymer block component is 2 (cal/cm 3 ) 1/2 or less.
11. The method for producing an electrode material for lithium secondary battery according to claim 9 , wherein
a solubility parameter difference between the first polymer block component and the first inorganic precursor is smaller than a solubility parameter difference between the first polymer block component and the second inorganic precursor.
12. The method for producing an electrode material for lithium secondary battery according to claim 9 , wherein
a solubility parameter difference between the second polymer block component and the second inorganic precursor is smaller than a solubility parameter difference between the second polymer block component and the first inorganic precursor.
13. The method for producing an electrode material for lithium secondary battery according to claim 9 , wherein
the block copolymer comprises at least one first polymer block component and at least one second polymer block component which are linked to each other, the first polymer block component being selected from the group consisting of a polystyrene component, a polyisoprene component, and a polybutadiene component, the second polymer block component being selected from the group consisting of a poly(methyl methacrylate) component, a poly(ethylene oxide) component, a polyvinylpyridine component, and a poly(acrylic acid) component,
the first inorganic precursor is at least one of organometallic compounds and organometalloidal compounds having at least one structure selected from the group consisting of a phenyl group, long hydrocarbon chains having 5 or more carbon atoms, a cyclooctatetraene ring, a cyclopentadienyl ring, and an amino group, and
the second inorganic precursor is at least one selected from the group consisting of salts of metals or metalloids, metal- or metalloid-containing alkoxides having 1 to 4 carbon atoms, and metal or metalloid acetylacetonate complexes.