Polymer nanocomposites for lithium battery applications

Abstract

A single ion-conducting nanocomposite of a substantially amorphous polyethylene ether and a negatively charged synthetic smectite clay useful as an electrolyte. Excess SiO 2 improves conductivity and when combined with synthetic hectorite forms superior membranes for batteries. A method of making membranes is also disclosed.

1 - 19 . (canceled)  
     
     
         20 . A single ion-conducting polymer electrolyte, comprising a nanocomposite of a substantially amorphous polyethylene ether intercalated in a negatively charged synthetic phyllosilicate clay having excess SiO 2  therein.  
     
     
         21 . The single ion-conducting polymer electrolyte of  claim 20 , wherein said synthetic phyllosilicate clay has platelets having a thickness in the range of from about 15 to about 40 nanometers.  
     
     
         22 . The single ion-conducting polymer electrolyte of  claim 21 , wherein said excess SiO 2  is present in the range of from about 15% to abut 25%.  
     
     
         23 . The single ion-conducting polymer electrolyte of  claim 22 , wherein said excess SiO 2  is present in an amount of about 20%.  
     
     
         24 . The single ion-conducting polymer electrolyte of  claim 22 , wherein said phyllosilicate clay is a hectorite.  
     
     
         25 . The single ion-conducting polymer electrolyte of  claim 24 , wherein said excess SiO 2  is present is in the form of spheres about 20 nanometers in diameter.  
     
     
         26 . The single ion-conducting polymer electrolyte of  claim 25 , wherein the mass ratio of polyethylene ether to hectorite clay is in the range of from about 0.5:1 to about 3:1.  
     
     
         27 . The single ion-conducting polymer electrolyte of  claim 26 , wherein said electrolyte is in the form of a membrane having a thickness in the range of from about 40 to about 60 micrometers.  
     
     
         28 . The single ion-conducting polymer electrolyte membrane of  claim 27 , wherein said membrane is on a backing material of glass or silicon.  
     
     
         29 . The single ion-conducting polymer electrolyte membrane of  claim 28 , wherein said negatively charged hectorite clay has Li+ ions therein.  
     
     
         30 . The single ion-conducting polymer electrolyte membrane of  claim 29 , wherein at least a portion of said polyethylene ether is polyethylene oxide having a molecular weight between about 80,000 and about 250,000.  
     
     
         31 . The single ion-conducting polymer electrolyte membrane of  claim 30 , wherein the mass ratio of polyethylene oxide to clay is in the range of from about 0.5:1 to about 1.5:1.  
     
     
         32 . The single ion-conducting polymer electrolyte membrane of  claim 31 , wherein the ion transport number is greater than 9.0.  
     
     
         33 . A single lithium-ion conducting polymer electrolyte membrane, comprising a nanocomposite of substantially amorphous polyethylene oxide intercalated in a negatively charged synthetic phyllosilicate clay having not less than about 15% excess SiO 2 .  
     
     
         34 . The single lithium-ion conducting polymer electrolyte membrane of  claim 33 , wherein said phyllosilicate clay has platelets having a thickness in the range of from about 15 to about 40 nanometers and the excess SiO 2  is in the form of spheres about 20 nanometers in diameter.  
     
     
         35 . The single lithium-ion conducting polymer electrolyte membrane of  claim 34 , wherein the lithium ion transport number is greater than 90.  
     
     
         36 . The single lithium-ion conducting polymer electrolyte membrane of  claim 35  and further including a substrate carrying said membrane.  
     
     
         37 . The single lithium-ion conducting polymer electrolyte membrane of  claim 36 , wherein said substrate is silicon or a glass.  
     
     
         38 . The single lithium-ion conducting polymer electrolyte membrane of  claim 37 , wherein the membrane has a thickness in the range from about 40 to about 60 micrometers; and the mass ratio of polyethylene oxide to clay is in the range of from abut 0.5:1 to about 1.5:1.  
     
     
         39 - 50 . (canceled)