Carbon-coated active material composite and lithium ion battery

Patent metadata

Field	Value
Publication number	US-2015255787-A1
Application number	US-201414430408-A
Country	US
Kind code	A1
Filing date	May 15, 2014
Priority date	May 16, 2013
Publication date	Sep 10, 2015
Grant date	—

Abstract

A carbon-coated active material composite, an electrode and a lithium ion battery capable of improving electron conductivity and lithium ion conductivity when an electrode active material having a carbonaceous film formed on the surface is used as an electrode material are provided. In the carbon-coated active material composite, charge migration of lithium ions occurs at an interface between a carbonaceous film and an electrode active material, an activation energy of an insertion and removal reaction of lithium ions at an interface between the carbon-coated active material composite and an electrolytic solution is 45 kJ/mol to 85 kJ/mol, a value of a carbon supported amount to a specific surface area of particles of an electrode active material is 0.01 to 0.5, and the activation energy is measured using an electrolyte solution obtained by mixing ethylene carbonate and diethyl carbonate at a 1:1 ratio.

First claim

1 . A carbon-coated active material composite in which charge migration of lithium ions occurs at an interface between a carbonaceous film and an electrode active material,
wherein an activation energy of an insertion and removal reaction of lithium ions occurring at an interface between the carbon-coated active material composite and an electrolytic solution is in a range of 45 kJ/mol to 85 kJ/mol, a value of a carbon supported amount with respect to a specific surface area of particles of an electrode active material, calculated as [carbon supported amount]/[specific surface area of the particles of the electrode active material], is in a range of 0.01 to 0.5, and the activation energy is a value measured using an electrolyte solution obtained by mixing ethylene carbonate and diethyl carbonate at a 1:1 ratio.

2 . A carbon-coated active material composite in which charge migration of lithium ions occurs at an interface between a carbonaceous film and an electrode active material,
wherein an activation energy of an insertion and removal reaction of lithium ions occurring at an interface between the carbon-coated active material composite and an electrolytic solution increases by a range of 5 kJ/mol to 40 kJ/mol compared with the activation energy of the insertion and removal reaction of lithium ions occurring at an interface between the electrode active material that is yet to be coated with carbon and the electrolytic solution, and a value of a carbon supported amount with respect to a specific surface area of particles of the electrode active material, calculated as [carbon supported amount]/[specific surface area of the particles of the electrode active material] is in a range of 0.01 to 0.5, and the activation energy is a value measured using an electrolyte solution obtained by mixing ethylene carbonate and diethyl carbonate at a 1:1 ratio.

3 . The carbon-coated active material composite according to claim 1 ,
wherein the carbonaceous film has a net-shaped structure, coats 70% or more of surfaces of the particles of the electrode active material, and a density of the carbonaceous film is in a range of 0.1 g/cm 3 to 1.5 g/cm 3 .

4 . The carbon-coated active material composite according to claim 1 ,
wherein a film thickness of the carbonaceous film is in a range of 0.1 nm to 10 nm.

5 . A lithium ion battery comprising:
a cathode which comprises the carbon-coated active material composite according to claim 1 .

Assignees

• Sumitomo Osaka Cement Co Ltd

Inventors

• Mine Hiroyuki
• Kitagawa Takao

Classifications

• H01M4/366 Primary

  as layered products · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title