Electrode for nonaqueous electrolyte battery

Abstract

The following aspects (1) to (4) of the present invention can provide an electrode for nonaqueous electrolyte battery having excellent safety and charged storage properties and good high rate charge-discharge properties. (1) An electrode for nonaqueous electrolyte battery including a particulate active material having a porous film formed thereon. (2) An electrode for nonaqueous electrolyte battery including an active material having a filler held in pores. (3) An electrode for nonaqueous electrolyte battery including an active material which undergoes volumetric expansion and shrinkage during charge-discharge, having a filler held in pores. (4) The electrode for nonaqueous electrolyte battery according to aspect (1), wherein the porous film is an ionically-conductive film.

1 . A process for the preparation of an electrode comprising a particulate active material having a porous film formed thereon, comprising the steps of: 
 covering a particulate active material by a porous film, and    then attaching said particulate active material to a current collector.    
     
     
         2 . A process as claimed in  claim 1 , comprising the steps of: 
 forming a slurry comprising said particulate active material covered with said porous film,    then coating said slurry on said current collector, and    then drying said slurry.    
     
     
         3 . A process as claimed in  claim 1 , wherein said current collector is made of iron, copper, aluminum, stainless steel or nickel.  
     
     
         4 . A process as claimed in  claim 1 , wherein said current collector is in the form of a sheet, foamed body or sintered porous body.  
     
     
         5 . A process as claimed in  claim 1 , wherein said electrode is for a nonaqueous electrolyte battery.  
     
     
         6 . A process as claimed in  claim 1 , wherein said electrode is for a lithium battery.  
     
     
         7 . A process as claimed in  claim 1 , wherein the active material is a carbon-based negative active material.  
     
     
         8 . A process as claimed in  claim 1 , comprising swelling said porous film with an electrolyte solution so that ions move through pores in the film and through said film formed on said particulate active material.  
     
     
         9 . A process as claimed in  claim 1 , comprising the steps of: 
 preparing a solution having a polymer dissolved in a solvent (a),    coating a particulate active material with said solution, and replacing said solvent (a) in said solution by a solvent (b), wherein said solvent (b) is soluble in said solvent (a) and said polymer is insoluble in said solvent (b).