Lithium-ion secondary battery, negative electrode for lithium-ion secondary battery, battery pack, electric vehicle, power storage system, electric tool, and electronic device

Abstract

A lithium-ion secondary battery includes a positive electrode, a negative electrode containing an active material, and an electrolytic solution, in which the active material contains, as constituent elements, Si, O, and at least one element M1 selected from Li, C, Mg, Al, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Ge, Zr, Mo, Ag, Sn, Ba, W, Ta, Na, and K, and the atomic ratio x (O/Si) of O to Si is 0.5≦x≦1.8.

The invention is claimed as follows: 
     
         1 : A lithium-ion battery comprising:
 a positive electrode;   a negative electrode including an active material; and   an electrolytic solution,   wherein the active material includes Si, O, and at least one element M1 selected from Li, C, Mg, Al, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Ge, Zr, Mo, Ag, Sn, Ba, W, Ta, Na, and K,   an atomic ratio x of O to Si is 0.5≦x≦1.8,   at least one of the atoms of Si is bonded to at least one of the atoms of O, with bonding states of Si atoms that include zero valence (Si 0+ ), monovalence (Si 1+ ), divalence (Si 2+ ), trivalence (Si 3+ ), and tetravalence (Si 4+ ), the proportion of Si 1+  is less than 10 atomic percent, and atomic ratios of the bonding states satisfy Si 4+ <Si 0+ +Si 1+ +Si 2+ +Si 3+ , Si 4+ >Si 0+ , Si 4+ ≧Si 1+ , and Si 4+ ≧Si 2+ .   
     
     
         2 : The lithium-ion battery according to  claim 1 , wherein an atomic ratio of M1/(Si+O) is 0.5 or less. 
     
     
         3 : The lithium-ion battery according to  claim 1 , wherein at least one of the atoms of M1 is bonded to at least one of Si and O. 
     
     
         4 : The lithium-ion battery according to  claim 3 , wherein the active material includes a compound of Si, O, and at least one of the atoms of M1. 
     
     
         5 : The lithium-ion battery according to  claim 1 , wherein the active material includes Li in an uncharged state. 
     
     
         6 : The lithium-ion battery according to  claim 1 , wherein the active material has a median diameter of 0.3 μm to 20 μm. 
     
     
         7 : The lithium-ion battery according to  claim 1 , wherein the negative electrode includes a conductive layer provided on at least part of a surface of the active material, the conductive layer having a lower electrical resistance than the active material. 
     
     
         8 : The lithium-ion battery according to  claim 7 , wherein the conductive layer includes a carbon material. 
     
     
         9 : The lithium-ion battery according to  claim 1 , wherein the negative electrode includes a binder that includes one or more of polyimide, polyamide-imide, polyamide, polyvinylidene fluoride, polyacrylic acid, lithium polyacrylate, sodium polyacrylate, polymaleic acid, copolymers thereof, carboxymethyl cellulose, styrene-butadiene rubber, and polyvinyl alcohol. 
     
     
         10 : The lithium-ion battery according to  claim 1 , wherein the active material is selected from the group consisting of an amorphous material and a low-crystallinity material. 
     
     
         11 : A battery pack comprising:
 the lithium-ion battery according to  claim 1 ;   a controller configured to control the usage state of the lithium-ion battery; and   a switching unit configured to switch the usage state of the lithium-ion battery in response to an instruction from the controller.   
     
     
         12 : An electric vehicle comprising:
 the lithium-ion battery according to  claim 1 ;   a conversion unit configured to convert power from the lithium-ion battery into a driving force;   a driven unit configured to be driven in response to the driving force; and   a controller configured to control the usage state of the lithium-ion battery.   
     
     
         13 : A power storage system comprising:
 the lithium-ion battery according to  claim 1 ;   one or more electrical devices; and   a controller configured to control the power supply from the lithium-ion battery to the electrical devices.   
     
     
         14 : An electric tool comprising:
 the lithium-ion battery according to  claim 1 ; and   a moving part powered by the lithium-ion battery.   
     
     
         15 : An electronic device comprising:
 the lithium-ion battery according to  claim 1 , wherein the electronic device is powered by the lithium-ion battery.   
     
     
         16 : A negative electrode comprising:
 an active material including Si, O, and at least one element M1 selected from Li, C, Mg, Al, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Ge, Zr, Mo, Ag, Sn, Ba, W, Ta, Na, and K,   an atomic ratio x of O to Si is 0.5≦x≦1.8,   at least one of the atoms of Si is bonded to at least one of the atoms of O, with bonding states of Si atoms that include zero valence (Si 0+ ), monovalence (Si 1+ ), divalence (Si 2+ ), trivalence (Si 3+ ), and tetravalence (Si 4+ ), the proportion of Si 1+  is less than 10 atomic percent, and atomic ratios of the bonding states satisfy Si 4+ <Si 0+ +Si 1+ +Si 2+ +Si 3+ , Si 4+ >Si 0+ , Si 4+ ≧Si 1+ , and Si 4+ ≧Si 2+ .   
     
     
         17 : The negative electrode according to  claim 16 , wherein an atomic ratio of M1/(Si+O) is 0.5 or less. 
     
     
         18 : The negative electrode according to  claim 16 , wherein at least one of the atoms of M1 is bonded to at least one of Si and O. 
     
     
         19 : The negative electrode according to  claim 16 , wherein the active material includes a compound of Si, O, and at least one of the atoms of M1. 
     
     
         20 : The negative electrode according to  claim 16 , wherein the active material is selected from the group consisting of an amorphous material and a low-crystallinity material.