Secondary batteries, electronic equipment, energy storage systems, and vehicles

Abstract

Provided is a secondary battery with high capacity and less degradation. Also provided is a novel power storage device. This secondary battery has a positive electrode and a negative electrode. The negative electrode has a first active material, a second active material, and a graphene compound. A region covered with the second active material is provided to at least part of the surface of the first active material. A region covered with the graphene compound is provided to at least part of the surface of the first active material and the surface of the second active material. The first active material includes graphite. The second active material includes silicon. With respect to the capacity of the negative electrode, the capacity of the positive electrode is not less than 50% but less than 100%.

Claims

[Claim 1] It has a positive electrode and a negative electrode, The negative electrode comprises a first active material, a second active material, and a graphene compound. At least a portion of the surface of the first active material has a region covered by the second active material, At least a portion of the surface of the second active material and at least a portion of the surface of the first active material have regions covered with the graphene compound. The first active material comprises graphite, The second active material described above has silicon, The graphene compound has a pore formed by a plurality of carbon atoms, one or more hydrogen atoms, and one or more fluorine atoms. Each of the one or more hydrogen atoms and the one or more fluorine atoms terminates on one of the plurality of carbon atoms. A secondary battery in which the capacity of the positive electrode is 50% or more and less than 100% of the capacity of the negative electrode. [Claim 2] It has a positive electrode, a negative electrode, and an electrolyte. The negative electrode comprises a first active material, a second active material, and a graphene compound. At least a portion of the surface of the first active material has a region covered by the second active material, At least a portion of the surface of the second active material and at least a portion of the surface of the first active material have regions covered with the graphene compound. The first active material comprises graphite, The second active material described above has silicon, The graphene compound has a pore composed of a plurality of carbon atoms, one or more hydrogen atoms, and one or more fluorine atoms. Each of the one or more hydrogen atoms and the one or more fluorine atoms terminates on one of the plurality of carbon atoms. The aforementioned silicon has at least a portion of its surface terminated with hydroxyl groups, The capacity of the positive electrode is 50% or more and less than 100% of the capacity of the negative electrode. The electrolyte is an ionic liquid, and the rechargeable battery is provided. [Claim 3] In claim 2, The ionic liquid comprises 2 mol / L or more of LiFSI and EMI-FSI, and is a secondary battery. [Claim 4] In any one of claims 1 to 3, The positive electrode has a positive electrode active material, The positive electrode active material comprises magnesium, fluorine, aluminum, nickel, and lithium cobalt oxide. A secondary battery wherein the positive electrode active material has a region on its surface where the concentration of one or more selected from magnesium, fluorine, and aluminum is maximum. [Claim 5] In any one of claims 1 to 4, A secondary battery in which nine or more carbon atoms are present on the outer circumference of the aforementioned hole. [Claim 6] In any one of claims 1 to 5, The aforementioned graphite has a particle size of 5 μm or larger. The aforementioned silicon has a particle size of 250 nm or less, and is used in a secondary battery. [Claim 7] A vehicle having a secondary battery as described in claim 6. [Claim 8] A power storage system having a secondary battery as described in claim 6. [Claim 9] An electronic device having a secondary battery as described in claim 6.

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