Method for producing an electrode containing electrolyte-absorbed polymer particles

Abstract

A method for producing a gelled anode for alkaline galvanic cells, specifically alkaline zinc-manganese dioxide cells, in which cross-linked electrolyte-absorbed polymer particles are distributed throughout the anode and the gelled anode so made.

The invention claimed is:  
     
         1 . A method for producing an electrode for use in a galvanic cell, comprising the steps of: 
 (a) selecting dehydrated liquid absorbing cross-linked polymer particles, wherein the liquid absorbing cross-linked polymer particles are made by mixing cross-linked polymer particles with water and then dehydrating the cross-linked polymer particles to produce the liquid absorbing cross-linked polymer particles; and    (b) mixing at least one electrochemically active material, an electrolyte solution, and the selected liquid absorbing cross-linked polymer particles of step (a), wherein, after absorbing the electrolyte, the liquid absorbing cross-linked polymer particles are increased in size and are substantially distributed throughout the electrode.    
     
     
         2 . The method of    claim 1    wherein in step (b), after absorbing the electrolyte, at least 50 percent of the liquid absorbing cross-linked polymer particles are at least 1,000 microns in length, width or height.  
     
     
         3 . The method of    claim 1    wherein the water is deionized water.  
     
     
         4 . The method of    claim 1    wherein step (a) further comprises: 
 allowing said dehydrated liquid absorbing cross-linked polymer particles to absorb electrolyte, thereby producing electrolyte-absorbed polymer particles; and  
 feeding said electrolyte absorbed particles into the mix of step (b).  
 
     
     
         5 . The method of    claim 1    wherein in step (a) the dehydrated liquid absorbing cross-linked polymer particles flow through a 40 Tyler mesh screen and are retained on a 200 Tyler mesh screen.  
     
     
         6 . The method of    claim 1    wherein in step (a) the dehydrated liquid absorbing cross-linked polymer particles flow through a 40 Tyler mesh screen and are retained on a 60 Tyler mesh screen.  
     
     
         7 . The method of    claim 1    wherein in step (b) at least 75% of the cross-linked electrolyte-absorbed polymer particles are at least 1000 microns in length, width or height.  
     
     
         8 . The method of    claim 7    wherein in step (b) at least 75% of the cross-linked electrolyte-absorbed polymer particles are between 1000 microns and 10,000 microns in length, width or height.  
     
     
         9 . The method of    claim 1    wherein in step (b) at least 80% of the cross-linked electrolyte-absorbed polymer particles are between 2000 microns and 6000 microns in length, width or height.  
     
     
         10 . A method for producing an electrode for use in a galvanic cell, comprising the steps of: 
 mixing liquid absorbing cross-linked polymer particles with water to provide absorbed cross-linked polymer particles;    dehydrating the absorbed cross-linked polymer particles to provide dehydrated liquid absorbing cross-linked polymer particles; and    mixing at least one electrochemically active material, an electrolyte solution, and the dehydrated liquid absorbing cross-linked polymer particles, wherein, after absorbing the electrolyte, the liquid absorbing cross-linked polymer particles are increased in size and are substantially distributed throughout the electrode.    
     
     
         11 . The method of    claim 10    further comprising the step of selecting the dehydrated liquid absorbing cross-linked polymer particles which are sized to flow through a 20 Tyler mesh screen and be retained on a 200 Tyler mesh screen for use in the step of mixing.  
     
     
         12 . The method of    claim 10    wherein, after absorbing the electrolyte, at least 50 percent of the liquid absorbing cross-linked polymer particles are at least 1,000 microns in length, width or height.  
     
     
         13 . The method of    claim 1    wherein the water is deionized water.  
     
     
         14 . The method of    claim 10    further comprising: 
 allowing said dehydrated liquid absorbing cross-linked polymer particles to absorb electrolyte thereby producing electrolyte-absorbed polymer particles; and  
 using said electrolyte absorbed polymer particles as the dehydrated liquid absorbing cross-linked polymer particles for the step of mixing.  
 
     
     
         15 . An electrode for use in an alkaline galvanic cell comprising an electrochemically active material, electrolyte, and cross-linked electrolyte-absorbed polymer particles, said cross-linked polymer particles selected from the group consisting of carboxyvinyl polymers and cross-linked polyacrylamide polymers; wherein said electrolyte-absorbed polymer particles are at least 1000 microns in length, width or height and are substantially distributed throughout the anode, and wherein the electrolyte-absorbed polymer particles are made by mixing cross-linked polymer particles with water and then dehydrating the cross-linked polymer particles to produce liquid absorbing cross-linked polymer particles.  
     
     
         16 . The electrode of    claim 15    further comprising a gelling agent, said gelling agent being distinguishable from the cross-linked electrolyte-absorbed polymer particles.  
     
     
         17 . The electrode of    claim 16    wherein said cross-linked electrolyte-absorbed polymer particles are present in an amount between about 15% by volume and about 50% by volume of the total volume occupied by the gelling agent and electrolyte-absorbed polymer particles.  
     
     
         18 . The electrode of    claim 17    wherein said electrochemically active material is zinc and said cross-linked electrolyte-absorbed polymer particles occupy between about 20% by volume and about 35% by volume of the total volume occupied by the gelling agent and electrolyte-absorbed polymer particles.  
     
     
         19 . An electrode for use in an alkaline galvanic cell comprising an electrochemically active material, electrolyte, and cross-linked electrolyte-absorbed polymer particles, wherein the electrolyte-absorbed polymer particles are made by mixing cross-linked polymer particles with water and then dehydrating the cross-linked polymer particles to produce liquid absorbing cross-linked polymer particles, and wherein, after absorbing the electrolyte, the liquid absorbing cross-linked polymer particles are increased in size and are substantially distributed throughout the electrode.  
     
     
         20 . The electrode of    claim 19    wherein said cross-linked polymer particles are selected from the group consisting of carboxylvinyl polymers and cross-linked polyacrylamide polymers.  
     
     
         21 . The electrode as defined in    claim 19    wherein said electrolyte-absorbed polymer particles are at least 1,000 microns in length, width or height.  
     
     
         22 . The electrode of    claim 19    further comprising a gelling agent, said gelling agent being distinguishable from the cross-linked electrolyte-absorbed polymer particles.  
     
     
         23 . The electrode of    claim 22    wherein said cross-linked electrolyte-absorbed polymer particles are present in an amount between about 15% by volume and about 50% by volume of the total volume occupied by the gelling agent and electrolyte-absorbed polymer particles.  
     
     
         24 . The electrode of    claim 23    wherein said electrochemically active material is zinc and said cross-linked electrolyte-absorbed polymer particles occupy between about 20% by volume and about 35% by volume of the total volume occupied by the gelling agent and electrolyte-absorbed polymer particles.