Microporous insulators

Abstract

Insulators and polymer-coated insulators are provided. The insulators can include thermally-insulating nanoparticles and a binder configured to volatilize at a volatilization temperature. Insulators can also include an inorganic thermally-insulating material forming a porous structure. The porous structure can be configured to reduce the mean free path of gases in the insulator as compared to gases outside the porous structure. Polymer-coated insulators including an inorganic thermally-insulating material and a polymer coating disposed on the surface of the inorganic thermally-insulating material are also provided. Insulators can also include thermally-insulating nanoparticles and an opacifier. The opacifier can include a carbonaceous material coated with a refractory material that inhibits oxidation of the carbonaceous material at a carbon oxidation temperature. The insulators or polymer-coated insulators can be disposed between battery cells or battery cell blocks in an apparatus.

1 . An insulator comprising:
 an inorganic thermally-insulating material having a porous structure; and   a binder that volatilizes at a volatilization temperature, the binder disposed within the porous structure, wherein the insulator comprises at least 10 vol % of the binder, wherein a thermal conductivity of the insulator is less than 0.05 W/m·K at 25° C. after volatilization of the binder, and   
       wherein a thermal conductivity of the insulator is greater than 0.1 W/m·K at 25° C. before volatilization of the binder. 
     
     
         2 .- 3 . (canceled) 
     
     
         4 . The insulator of  claim 1 , wherein the porous structure has a mean pore diameter of less than 500 nm. 
     
     
         5 . The insulator of  claim 1 , wherein the inorganic thermally-insulating material comprises thermally-insulating nanoparticles disposed in contact with each other to define the porous structure. 
     
     
         6 . The insulator of  claim 5 , wherein the thermally-insulating nanoparticles have a mean particle size of less than 100 nm. 
     
     
         7 . (canceled) 
     
     
         8 . The insulator of  claim 1 , wherein the inorganic thermally-insulating material is selected from silica, carbon, zirconia, titania, and a ceramic. 
     
     
         9 .- 14 . (canceled) 
     
     
         15 . The insulator of  claim 1 , wherein the binder is a material selected from a polyalkyl carbonate, a polyacrylate, a polyether, a polyaryl carbonate, a polyol, a polytetrafluoropenthylene (PTFE), a polyvinyl alcohol, a lignosulfonate, methylcellulose, a paraffin, a silicone, an organo-silane, a starch, a dextrin, and a wax emulsion. 
     
     
         16 . The insulator of  claim 1 , wherein the binder is selected from polypropylene carbonate, polyethylene carbonate, and polyhexane carbonate. 
     
     
         17 .- 19 . (canceled) 
     
     
         20 . The insulator of  claim 1 , wherein the binder has a volatilization temperature not greater than 500° C. at 1 atmosphere pressure. 
     
     
         21 . The insulator of any  claim 1 , further comprising a fibrous material in contact with the inorganic thermally-insulating material. 
     
     
         22 .- 46 . (canceled) 
     
     
         47 . The insulator of  claim 1 , further comprising an opacifier that comprises silicon carbide, titania, or a carbonaceous material. 
     
     
         48 .- 56 . (canceled) 
     
     
         57 . A polymer-coated insulator comprising:
 an inorganic thermally-insulating material; and   a polymer coating disposed on a surface of the inorganic thermally-insulating material and penetrating at least an average of 10 microns into the inorganic thermally-insulating material,   wherein a thermal conductivity of the insulator is less than 0.05 W/m·K at 25° C.   
     
     
         58 . (canceled) 
     
     
         59 . The polymer-coated insulator of  claim 57 , wherein the inorganic thermally-insulating material comprises thermally-insulating nanoparticles disposed in contact with each other to define a porous structure having a mean pore diameter of less than 500 nm. 
     
     
         60 .- 62 . (canceled) 
     
     
         63 . The polymer-coated insulator of  claim 57 , wherein the inorganic thermally-insulating material is selected from silica, carbon, zirconia, titania, and ceramic. 
     
     
         64 .- 65 . (canceled) 
     
     
         66 . The polymer-coated insulator of  claim 57 , wherein the inorganic thermally-insulating material comprises ceramic nanoparticles, the ceramic nanoparticles comprising fumed silica or silica aerogel. 
     
     
         67 . The polymer-coated insulator of  claim 57 , wherein the inorganic thermally-insulating material is at least 5 volume % of the insulator. 
     
     
         68 . The polymer-coated insulator of  claim 57 , wherein the polymer coating has a thickness of less than or equal to 300 microns. 
     
     
         69 . The polymer-coated insulator of  claim 57 , wherein the polymer coating is a material selected from polyurethane, an epoxy, a polyacrylate, a polyester, and a polyimide. 
     
     
         70 . (canceled) 
     
     
         71 . The polymer-coated insulator of  claim 57 , further comprising an opacifier having a mean extinction coefficient greater than 1×10 4  m −1  at temperatures greater than 250° C. 
     
     
         72 . The polymer-coated insulator of  claim 71 , wherein the opacifier comprises silicon carbide, titania, or a carbonaceous material. 
     
     
         73 .- 102 . (canceled) 
     
     
         103 . An apparatus comprising:
 a first battery cell and a second battery cell; and   an insulator of  claim 57 , disposed between the first battery cell and the second battery cell.   
     
     
         104 .- 121 . (canceled)