Nonaqueous electrolyte secondary battery and method for manufacturing nonaqueous electrolyte secondary battery

Abstract

In a nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode and a nonaqueous electrolytic solution, the nonaqueous electrolytic solution contains a nitrile compound having a chain saturated hydrocarbon group and a nitrile group, the number of carbon atoms in the nitrile compound is four or more, and the positive electrode contains a positive-electrode active material on the surface of which particles of a rare earth element compound are deposited in dispersed form.

What is claimed is: 
     
         1 . A nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode and a nonaqueous electrolytic solution, wherein
 the nonaqueous electrolytic solution contains a nitrile compound having a chain saturated hydrocarbon group and a nitrile group,   the number of carbon atoms in the nitrile compound is four or more, and   the positive electrode contains a positive-electrode active material comprising a lithium-containing transition metal composite oxide on the surface of which particles of a rare earth compound are uniformly dispersed deposits;   wherein the rare earth compound comprises at least one selected from the group consisting of erbium, ytterbium, terbium, dysprosium, holmium, thulium, and lutetium, and   wherein the particles of the rare earth compound have an average particle diameter of 100 nm or less,   wherein the lithium-containing transition metal composite oxide consists of only one type.   
     
     
         2 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein the nitrile compound has two or more nitrile groups. 
     
     
         3 . The nonaqueous electrolyte secondary battery according to  claim 2 , wherein the nitrile compound is at least one selected from glutaronitrile, adiponitrile and pimelonitrile. 
     
     
         4 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein the rare earth compound is a hydroxide or an oxyhydroxide. 
     
     
         5 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein an amount of the rare earth compound deposited on the positive-electrode active material is within the range from 0.005% to 0.3% by mass. 
     
     
         6 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein the rare earth compound is erbium. 
     
     
         7 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein the lithium-containing transition metal composite oxide is only one type selected from lithium cobalt oxide,
 Ni—Co—Mn-containing lithium composite oxide,   Ni—Mn—Al-containing lithium composite oxide and   Ni—Co—Al-containing lithium composite oxide.   
     
     
         8 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein the lithium-containing transition metal composite oxide is only one type selected from lithium cobalt oxide, Ni—Co—Mn-containing lithium composite oxide and Ni—Co—Al-containing lithium composite oxide. 
     
     
         9 . The nonaqueous electrolyte secondary battery according to  claim 8 , wherein only the particles of the rare earth compound are uniformly dispersed deposits on the lithium-containing transition metal composite oxide. 
     
     
         10 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein the particles of the rare earth compound have an average particle diameter of 100 nm or less. 
     
     
         11 . The nonaqueous electrolyte secondary battery according to  claim 1 , wherein the rare earth compound comprises at least one selected from the group consisting of a hydroxide, an oxyhydroxide and an oxide.