US 2022/0020981 A1 · POSITIVE ELECTRODE ACTIVE MATERIAL, SECONDARY BATTERY, ELECTRONIC DEVICE, AND VEHICLE

Abstract

A positive electrode active material for a lithium ion secondary battery which has a large capacity and a good charge-and-discharge cycle performance is provided. The positive electrode active material includes lithium, cobalt, oxygen, and magnesium, and has a compound represented by a layered rock-salt crystal structure. A space group of the compound is represented by R-3m. The compound is a composite oxide in which magnesium is substituted for a lithium position and a cobalt position. The compound is a particle. The magnesium substituted for a lithium position and a cobalt position exists more in the region from the surface to 5 nm than in the region deeper than 10 nm from the surface. More magnesium is substituted for a lithium position than for a cobalt position.

Claims15

Dependent claims

A positive electrode active material comprising:

a compound comprising lithium, cobalt, oxygen, and magnesium;
and
wherein a space group of the compound is represented as R-3m,
wherein the compound is a compound in which magnesium is substituted for a lithium position and a cobalt position in a composite oxide comprising lithium and cobalt,
wherein the compound is a particle,
wherein magnesium substituted for the lithium position and the cobalt position exists more in a region from a surface of the particle to a depth of 5 nm than in a region at a depth of 10 nm or more from the surface, and
wherein more magnesium is substituted for the lithium position than for the cobalt position.

4 more elements

A secondary battery,

a positive electrode, and
wherein the positive electrode is taken out from the secondary battery,
wherein a charging voltage is V and an amount of change of V is dV,
wherein a charging capacity is Q and an amount of change of Q is dQ,
wherein a dQ/dV vs V curve is measured using lithium metal as a counter electrode of the positive electrode,
wherein in the dQ/dV vs V curve which shows a relation between dQ/dV, which is a ratio of dQ to dV, and V,
the dQ/dV vs V curve is measured at a rate greater than or equal to 0.1 C and less than or equal to 1.0 C at a temperature greater than or equal to of 10° C. and less than or equal to 35° C.,
the dQ/dV vs V curve is measured twice within the V range greater than or equal to 4.54 V and less than or equal to 4.58 V, and
the dQ/dV vs V curve comprises a first peak in the second measurement within the V range greater than or equal to 4.54 V and less than or equal to 4.58 V, and
wherein the voltage is a voltage with reference to a redox potential of lithium metal.

7 more elements

A secondary battery,

a positive electrode, and
wherein the positive electrode is taken out from the secondary battery,
wherein a charging voltage is V and an amount of change of V is dV,
wherein a charging capacity is Q and an amount of change of Q is dQ,
wherein a dQ/dV vs V curve is measured using lithium metal as a counter electrode of the positive electrode,
wherein in the dQ/dV vs V curve which shows a relation between dQ/dV, which is a ratio of dQ to dV, and V,
the dQ/dV vs V curve is measured at a rate greater than or equal to 0.1 C and less than or equal to 1.0 C at a temperature greater than or equal to of 10° C. and less than or equal to 35° C.,
the dQ/dV vs V curve is repeatedly measured within the V range greater than or equal to 4.05 V and less than or equal to 4.58 V,
the dQ/dV vs V curve comprises a first peak within the V range greater than or equal to 4.54 V and less than or equal to 4.58 V,
the dQ/dV vs V curve comprises a second peak within the V range greater than or equal to 4.08 V and less than or equal to 4.18 V, and
the dQ/dV vs V curve comprises a third peak within the V range greater than or equal to 4.18 V and less than or equal to 4.25 V,
wherein the voltage is a voltage with reference to a redox potential of lithium metal,
wherein a peak intensity of the first peak increases in 1st to 10th measurements,
wherein the peak intensity of the first peak decreases in 30th to 100th measurements, and
wherein a voltage at a peak position of the second peak increases in the 30th to 100th measurements.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application

17/292,471Filed 7 Nov 2019

Priority

JP 2018-21595616 Nov 2018

Published

20 Jan 2022

Term ends

Not estimatedThe source records don’t support an estimate.

Classification27 codes

H01M 4/525
Of nickel, cobalt or iron: of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g.…
C01G 51/42
Complex oxides containing cobalt and at least one other metal element: containing alkali metals, e.g. LiCoO2
C01G 53/42
Complex oxides containing nickel and at least one other metal element: containing alkali metals, e.g. LiNiO2
H01M 4/382
Alkaline or alkaline earth metals elements: lithium

Positive electrode active material, secondary battery, electronic device, and vehicle

Life of this patent

Positive electrode active material, secondary battery, electronic device, and vehicle

Life of this patent

Abstract

Claims15