Lithium secondary battery and method of manufacturing the lithium secondary battery

Abstract

A lithium secondary battery comprising at least a negative electrode, a positive electrode and an electrolyte, and utilizing oxidizing and reducing reactions of lithium ions for charging and discharging, wherein an electrode having an active material which has at least an amorphous phase and a half value width not smaller than 0.48 degrees of a peak having a highest diffraction intensity at 2θ on an X-ray diffractometric chart traced at a diffraction intensity at an X-ray diffraction angle of 2θ, and is made of a material which has an amorphous phase and contains at least one element selected from among cobalt, nickel, manganese and iron is used as the negative electrode and/or the positive electrode.

What is claimed is:  
     
         1 . A lithium secondary battery comprising at least a negative electrode, a positive electrode and an electrolyte, and utilizing oxidation and reduction reactions of lithium ions for charging and discharging, 
 wherein an electrode having an active material which has at least an amorphous phase, exhibits peaks having a half value width not narrower than 0.48 degrees at a highest diffraction intensity at 2θ on an X-ray diffractometric chart traced at a diffraction intensity at an X-ray diffraction angle of 2θ, and is made of a material having an amorphous phase and containing one or more kinds of elements selected from among cobalt, nickel, manganese and iron is used as said negative electrode and/or said positive electrode.    
     
     
         2 . A lithium secondary battery according to  claim 1 , wherein an electrode having an active material made of a compound having said amorphous phase is used as a positive electrode.  
     
     
         3 . A lithium secondary battery according to  claim 1 , wherein an electrode having an active material made of a compound having said amorphous phase is used as a negative electrode.  
     
     
         4 . A lithium secondary battery according to claim  1 , wherein electrodes having an active material made of a compound having said amorphous phase are used as a positive electrode and a negative electrode and 
 wherein said active material has different compositions in the positive electrode and the negative electrode.    
     
     
         5 . A lithium secondary battery according to  claim 2  or  4 , wherein said positive electrode contains lithium in a condition where the battery is discharging.  
     
     
         6 . A lithium secondary battery according to  claim 3  or  4 , wherein said negative electrode contains lithium in a condition where the battery is charging.  
     
     
         7 . A lithium secondary battery according to  claim 1 , wherein said active material is a composite consisting of a material which contains at least one element selected from among cobalt, nickel, manganese and iron and a material which is made electrochemically inactive in the electrode in which said active material is used during a charging/discharging reaction of the lithium battery, and 
 wherein the electrode having said active material is a positive electrode.    
     
     
         8 . A lithium secondary battery according to  claim 1 , wherein said active material is a composite consisting of a material which contains at least one element selected from among cobalt, nickel, manganese and iron and a material which is electrochemically inactive to substances other than lithium in the electrode in which said active material is used during a charging/discharging reaction of the lithium battery, and 
 wherein the electrode having said active material is a negative electrode.    
     
     
         9 . A lithium secondary battery according to  claim 1 , wherein said active material has a crystallite size not exceeding 200 Å.  
     
     
         10 . A lithium secondary battery according to  claim 1 , wherein an X-ray diffraction intensity on the ( 003 ) surface of said active material is two or more times as high as that on the ( 104 ) surface.  
     
     
         11 . A lithium secondary battery according to  claim 1 , wherein a battery voltage varies curvilinearly relative to a discharging capacity with no plateau region during constant current discharging.  
     
     
         12 . A lithium secondary battery according to  claim 1 , wherein an open voltage has no plateau region relative to a storage capacity.  
     
     
         13 . A lithium secondary battery comprising at least a negative electrode, a positive electrode and an electrolyte, and utilizing an oxidation/reduction reactions of lithium ions for charging/discharging, 
 wherein the negative electrode has as an active material a composite consisting of a material which contains an amorphous phase, has a half value width not narrower than 0.48 degrees of a peak having a highest diffraction intensity relative to 2θ in X-ray diffractometry and contains at least one element selected from among metal element having an amorphous phase and carbon, and a material which is electrochemically inactive to substances other than lithium in the electrode in which said active material is used during a charging/discharging reaction of the lithium battery.    
     
     
         14 . A lithium secondary battery according to  claim 13 , wherein said positive electrode has an active material which has at least an amorphous phase and a half value width not narrower than 0.48 degrees of a peak having a highest diffraction intensity at 2θ on an X-ray diffractometric chart traced at diffraction intensity at an X-ray diffraction angle of 2θ, and made of a material having an amorphous phase and containing at least one element selected from among cobalt, nickel, manganese and iron.  
     
     
         15 . A lithium secondary battery according to  claim 13  or  14 , wherein said positive electrode contains lithium in a condition where the battery is discharging.  
     
     
         16 . A lithium secondary battery according to  claim 13  or  14 , wherein said negative electrode contains lithium in a condition where the battery is charging.  
     
     
         17 . A lithium secondary battery according to  claim 13 , wherein the active material in said negative electrode has a crystallite size not exceeding 200 Å.  
     
     
         18 . A lithium secondary battery according to  claim 13 , wherein said material which has the amorphous phase and contains the metal element is a metal material containing at least one element selected from among Al, Mg, Pb, K, Na, Ca, Sr, Ba, Si, Ge, Sn and In which are alloyed with lithium separated out by an electrochemical reaction.  
     
     
         19 . A lithium secondary battery according to  claim 13 , wherein said material which has the amorphous phase and contains the metal element is a metal material containing at least one element selected from among Ni, Co, Ti, Cu, Ag, Au, W, Mo, Fe, Pt and Cr which are not alloyed with lithium separated out by an electrochemical reaction.  
     
     
         20 . A lithium secondary battery according to  claim 13 , wherein said carbon material which has the amorphous phase consists of carbon having a graphite skeleton structure.  
     
     
         21 . A manufacturing method of a lithium secondary battery, wherein a material having an amorphous phase is prepared by imparting a physical energy to a crystalline material and 
 wherein an electrode is formed using said material having the amorphous phase as an active material for positive electrode or as an active material for negative electrode.    
     
     
         22 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said crystalline material contains at least one element selected from among cobalt, nickel, manganese and iron.  
     
     
         23 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein a material having an amorphous phase is prepared by mixing said crystalline material with a material which is electrochemically inactive in the electrode in which said active material is used during a charging/discharging reaction of the lithium battery, and 
 wherein said material having the amorphous phase is used as an active material for positive electrode.    
     
     
         24 . A manufacturing method of a lithium secondary battery according to  claim 23 , wherein a metal which has a less noble standard electrode potential is used as the material which is electrochemically inactive in the electrode in which said active material is used during the charging/discharging reaction of said lithium battery.  
     
     
         25 . A manufacturing method of a lithium secondary battery according to  claim 23 , wherein a carbon material is used as the material which is electrochemically inactive in the electrode in which said active material is used during the charging/discharging reaction of said lithium battery.  
     
     
         26 . A manufacturing method of a lithium secondary battery according to  claim 23 , wherein a transition-metal compound is used as the material which is electrochemically inactive in the electrode in which said active material is used during the charging/discharging reaction of said lithium battery.  
     
     
         27 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein a material having an amorphous phase is prepared by mixing a material which is electrochemically inactive to substances other than lithium in an electrode in which said active material is used during a charging/discharging reaction of the lithium battery with said a crystalline material and 
 wherein said material having the amorphous phase is used as an active material for negative electrode.    
     
     
         28 . A manufacturing method of a lithium secondary battery according to  claim 27 , wherein a metal having a noble standard electrode potential is used as said material which is electrochemically inactive to the substances other than lithium in the electrode in which said active material is used during the charging/discharging reaction of the lithium battery.  
     
     
         29 . A manufacturing method of a lithium secondary battery according to  claim 27 , wherein a carbon material is used as said material which is electrochemically inactive to the substances other than lithium in the electrode in which said active material is used during the charging/discharging reaction of the lithium battery.  
     
     
         30 . A manufacturing method of a lithium secondary battery according to  claim 27 , wherein a transition-metal compound is used as said material which is electrochemically inactive to the substances other than lithium in the electrode in which said active material is used during the charging/discharging reaction of the lithium battery.  
     
     
         31 . A manufacturing method of a lithium secondary battery according to  claim 27 , wherein a transition-metal compound is used as said material which is electrochemically inactive to the substances other than lithium during the charging/discharging reaction of the lithium battery.  
     
     
         32 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said physical energy is imparted to said crystalline material by a centrifugal force from inside a body of rotation.  
     
     
         33 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said crystalline material is heated after said physical energy is imparted to the material.  
     
     
         34 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said crystalline material is heated while said physical energy is being imparted to the material.  
     
     
         35 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said physical energy is imparted to said crystalline material by rotating a vessel which accommodates said crystalline material.  
     
     
         36 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said physical energy is imparted to said crystalline material in oxidizing atmosphere, reducing atmosphere or inert gas atmosphere.  
     
     
         37 . A manufacturing method of a lithium secondary battery according to  claim 36 , wherein said physical energy is imparted to said crystalline material in oxidizing atmosphere consisting of at least a gas selected from among oxygen, ozone air, water, vapor and ammonia.  
     
     
         38 . A manufacturing method of a lithium secondary battery according to  claim 36 , wherein said physical energy is imparted to said crystalline material in reducing atmosphere of hydrogen gas or a mixture gas consisting of hydrogen and an inert gas.  
     
     
         39 . A manufacturing method of a lithium secondary battery according to  claim 36 , wherein said physical energy is imparted to said crystalline material in inert gas atmosphere consisting of at least a gas selected from among argon gas, helium gas and nitrogen gas.  
     
     
         40 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said crystalline material is further treated with oxygen plasma or nitrogen plasma after said physical energy is imparted to the crystalline material.  
     
     
         41 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said crystalline material is cooled after said physical energy is imparted to the material.  
     
     
         42 . A manufacturing method of a lithium secondary battery according to  claim 33  or  34 , wherein said crystalline material is cooled after it is heated.  
     
     
         43 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein a half value width of an X-ray diffraction peak of the ( 003 ) surface or the ( 104 ) surface of said crystalline material after it is treated so as to have non-crystallinity is 10% or more higher than a half value width of the material before it has the non-crystallinity.  
     
     
         44 . A manufacturing method of a lithium secondary battery according to  claim 21 , wherein said crystalline material has, after being treated so as to have non-crystallinity, a crystallite size not larger than 50% of a crystallite size of the material before it has the non-crystallinity.