Lithium ion rechargeable battery and process for producing the lithium ion rechargeable battery

Abstract

Conventional ion rechargeable batteries having an electrode layer on an electrolyte layer suffer from an impurity layer formed at the interface, degrading performance. Conventional batteries with no such impurity layer have a problem of weak interface bonding. In the present invention, in a baking process step after an electrode layer is laminated on an electrolyte layer, materials for an electrode layer and an electrolyte layer are selected such that an intermediate layer formed of a reaction product contributing to charging and discharging reactions is formed at the interface of the electrode layer and the electrolyte layer. In addition, a paste that an active material is mixed with a conductive material at a predetermined mixing ratio is used to form a positive electrode layer and a negative electrode layer. Reductions in electrode resistance and interface resistance and improvement of charging and discharging cycle characteristics are made possible.

1 - 26 . (canceled) 
     
     
         27 . A multilayer all solid state lithium ion rechargeable battery characterized by comprising:
 a multilayered product having a positive electrode layer containing a positive active material laminated on a negative electrode layer containing a negative active material through an electrolyte layer containing a solid electrolyte,   wherein an intermediate layer formed of a substance that functions as an active material or an electrolyte is included at an interface of the positive electrode layer and/or the negative electrode layer and the electrolyte layer, the intermediate layer is a layer formed from a reaction and/or diffusion between the positive active material and/or the negative active material and the solid electrolyte.   
     
     
         28 . The lithium ion rechargeable battery according to  claim 27 , characterized in that the positive electrode layer and/or the negative electrode layer has a structure in which an active material is supported in a conductive matrix formed of a conductive material. 
     
     
         29 . The lithium ion rechargeable battery according to  claim 28 , characterized in that an area ratio between the positive active material and/or the negative active material and the conductive material in a cross section of the positive electrode layer and/or the negative electrode layer is within a range of 20:80 to 65:35. 
     
     
         30 . The lithium ion rechargeable battery according to  claim 27 , characterized in that the intermediate layer is a layer formed from a reaction between the positive active material and/or the negative active material and the solid electrolyte. 
     
     
         31 . A multilayer all solid state lithium ion rechargeable battery characterized by comprising:
 a multilayered product having a positive electrode layer containing a positive active material laminated on a negative electrode layer containing a negative active material through an electrolyte layer containing a solid electrolyte,   wherein a part or all of the positive electrode layer is formed of a sintered compact produced from a reaction and/or diffusion between a starting material for the positive active material contained in the positive electrode layer before baked and a starting material for the solid electrolyte contained in the electrolyte layer before baked.   
     
     
         32 . A multilayer all solid state lithium ion rechargeable battery characterized by comprising:
 a multilayered product having a positive electrode layer containing a positive active material laminated on a negative electrode layer containing a negative active material through an electrolyte layer containing a solid electrolyte,   wherein a part or all of the negative electrode layer is formed of a sintered compact produced from a reaction and/or diffusion between a starting material for the negative active material contained in the negative electrode layer before baked and a starting material for the solid electrolyte contained in the electrolyte layer before baked.   
     
     
         33 . A multilayer all solid state lithium ion rechargeable battery characterized by comprising:
 a multilayered product having a positive electrode layer containing a positive active material laminated on a negative electrode layer containing a negative active material through an electrolyte layer containing a solid electrolyte,   wherein a part or all of the electrolyte layer is formed of a sintered compact produced from a reaction and/or diffusion between a starting material for the positive active material contained in the positive electrode layer before baked a starting material for the solid electrolyte contained in the electrolyte layer before baked, and/or formed of a sintered compact produced from a reaction and/or diffusion between a starting material for the negative active material contained in the negative electrode layer before baked and a starting material for the solid electrolyte contained in the electrolyte layer before baked.   
     
     
         34 . The lithium ion rechargeable battery according to  claim 31 , characterized in that the positive electrode layer and/or the negative electrode layer has a structure in which an active material is supported in a conductive matrix formed of a conductive material. 
     
     
         35 . The lithium ion rechargeable battery according to  claim 34 , characterized in that an area ratio between the positive active material and/or the negative active material and the conductive material in a cross section of the positive electrode layer and/or the negative electrode layer is within a range of 20:80 to 65:35. 
     
     
         36 . The lithium ion rechargeable battery according to  claim 27 , characterized in that the positive electrode layer, the negative electrode layer, and/or the electrolyte layer is formed of a substance that functions as an active material or an electrolyte formed from a reaction between a starting material for the positive active material and/or a starting material for the negative active material and a starting material for the solid electrolyte. 
     
     
         37 . The lithium ion rechargeable battery according to  claim 27 , characterized in that an oxide containing no lithium is not included in a substance forming the intermediate layer or the sintered compact. 
     
     
         38 . The lithium ion rechargeable battery according to  claim 27 , characterized in that a starting material for the solid electrolyte contains at least a complex oxide of lithium and a IV group element. 
     
     
         39 . The lithium ion rechargeable battery according to  claim 27 , characterized in that a starting material for the solid electrolyte contains at least a lithium silicate. 
     
     
         40 . The lithium ion rechargeable battery according to  claim 27 , characterized in that a starting material for the solid electrolyte contains at least a lithium silicate and a lithium phosphate. 
     
     
         41 . The lithium ion rechargeable battery according to  claim 40 , characterized in that a mixing ratio between the lithium silicate and the lithium phosphate is within a range of 4:6 to 6:4. 
     
     
         42 . The lithium ion rechargeable battery according to  claim 27 , characterized in that the thickness of the electrolyte layer is 30 μm or below. 
     
     
         43 . The lithium ion rechargeable battery according to  claim 27 , characterized in that a starting material for the positive active material or the negative active material contains a substance or a plurality of substances selected from a substance group of a lithium manganese oxide, lithium nickel oxide, lithium cobalt oxide, lithium vanadium oxide, lithium titanium oxide, manganese dioxide, titanium oxide, niobium oxide, vanadium oxide, and tungsten oxide. 
     
     
         44 . The lithium ion rechargeable battery according to  claim 43 , characterized in that a starting material for the positive active material contains a lithium manganese oxide. 
     
     
         45 . The lithium ion rechargeable battery according to  claim 44 , characterized in that a starting material for the positive active material contains Li x Mn y O z  (where x=1 to 2, y=1 to 2, and z=2 to 4). 
     
     
         46 . The lithium ion rechargeable battery according to  claim 43 , characterized in that a starting material for the negative active material contains a lithium titanium oxide. 
     
     
         47 . The lithium ion rechargeable battery according to  claim 46 , characterized in that a starting material for the positive active material contains Li x Ti y O z  (where x=1 to 2, y=1 to 5/3, and z=2 to 4). 
     
     
         48 . A method of manufacture of a lithium ion rechargeable battery characterized by comprising the steps of:
 alternately laminating a positive electrode layer green sheet and a negative electrode layer green sheet through at least an electrolyte layer green sheet to form a multilayered product; and   collectively baking the multilayered product to form a sintered multilayered product,   wherein a starting material for the electrolyte layer contains at least a complex oxide of lithium and a IV group element.   
     
     
         49 . A method of manufacture of a lithium ion rechargeable battery characterized by comprising the steps of:
 dispersing at least a solid electrolyte material in a binder and a solvent to form a solid electrolyte layer paste;   coating and drying the solid electrolyte layer paste to form a solid electrolyte layer green sheet;   mixing an active material with a conductive material, and dispersing the materials in a binder and a solvent to form a positive electrode layer paste and/or a negative electrode layer paste;   coating and drying the positive electrode layer paste and/or the negative electrode layer paste to form a positive electrode layer green sheet and/or a negative electrode layer green sheet;   alternately laminating the positive electrode layer green sheet and the negative electrode layer green sheet through the solid electrolyte layer green sheet to form a multilayered product; and   collectively baking the multilayered product to form a sintered multilayered product,   wherein a starting material for the electrolyte layer contains at least a complex oxide of lithium and a IV group element.   
     
     
         50 . The method of manufacture of a lithium ion rechargeable battery according to  claim 49 , characterized in that a mixing ratio of mixing the active material with the conductive material is within a range of 20:80 to 65:35 in a volume ratio. 
     
     
         51 . The method of manufacture of a lithium ion rechargeable battery according to  claim 48 , characterized in that a baking temperature in the baking step ranges from temperatures of 600° C. or greater to 1100° C. or below. 
     
     
         52 . The method of manufacture of a lithium ion rechargeable battery according to  claim 48 , characterized in that a baking temperature in the baking step ranges from temperatures of 800° C. or greater to 1050° C. or below.