Electrolyte material, battery assembly, and production method

Abstract

One variation of a method for fabricating an electrolyte includes: depositing an electrolyte material over a substrate, the electrolyte material including a monomer miscible in a first volume of solvent, a polymer semi-miscible in the monomer and miscible in the first volume of solvent, and a photoinitiator; exposing the electrolyte material to electromagnetic radiation to disassociate the photoinitiator into a reactive subspecie that crosslinks the monomer to form an electrolyte structure with the polymer phase-separated from the electrolyte structure; dissolving the polymer out of the electrolyte structure with a second volume of solvent to render a network of open-cell pores in the electrolyte structure; and exposing the electrolyte structure to a third volume of solvent and ions to fill the network of open-cell pores with solvated ions.

I claim: 
     
         1 . An electrolyte material comprising:
 in a first form:
 a first proportion of a monomer miscible in a solvent; 
 a second proportion of a polymer semi-miscible in the monomer and miscible in the solvent; and 
 a photoinitiator configured to disassociate into a reactive subspecie responsive to exposure to electromagnetic radiation, the reactive subspecie configured to crosslink the monomer; and 
   in a second form:
 the first proportion of the monomer crosslinked by the reactive subspecie to form an electrolyte structure immiscible in the solvent; and 
 the second proportion of the polymer miscible in the solvent and phase-separated from the crosslinked monomer that forms the electrolyte structure. 
   
     
     
         2 . The composition of  claim 1 , wherein, in the first form:
 the first proportion of the monomer comprises monomers of bisphenol a novolac epoxy; and   the second proportion of the polymer comprises a blend of Poly(methyl methacrylate) molecules within a first narrow range of molecular weights and Poly(methyl methacrylate) molecules in a second narrow range of molecular weights greater than the first narrow range of molecular weights.   
     
     
         3 . The composition of  claim 2 :
 wherein, in the first form, the first proportion of the monomer, the second proportion of the polymer, and the photoinitiator are dissolved in the solvent and deposited over a silicon anode defining a three-dimensional surface;   wherein, in the second form:
 the photoinitiator is dissociated into the reactive subspecie by exposure to electromagnetic radiation; 
 the reactive subspecie locally crosslinks the monomer to form the electrolyte structure conforming around the three-dimensional surface of the silicon anode; and 
 the polymer phase-separates from the monomer, crosslinked by the reactive subspecie, and entangles to form an unlinked network throughout the electrolyte structure; and 
   comprising:
 in a third form, the second proportion of the polymer dissolved out of the electrolyte structure by the solvent to render a network of open-cell pores in the electrolyte structure; and 
 in a fourth form, the first proportion of the monomer crosslinked by the reactive subspecie and defining the electrolyte structure comprising the network of open-cell pores filled with a volume of solvated lithium ions and solvent to form an electrolyte. 
   
     
     
         4 . The electrolyte material of  claim 1 , comprising:
 in a third form, the second proportion of the polymer dissolved out of the electrolyte structure by the solvent to render a network of open-cell pores in the electrolyte structure; and   in a fourth form, the first proportion of the monomer crosslinked by the reactive subspecie and defining the electrolyte structure comprising the network of open-cell pores filled with a volume of solvated ions and solvent to form an electrolyte.   
     
     
         5 . The composition of  claim 4 :
 wherein, in the first form, the first proportion of the monomer, the second proportion of the polymer, and the photoinitiator are dissolved in the solvent and deposited over an anode defining a three-dimensional surface;   wherein, in the second form and the third form, the first proportion of the monomer is crosslinked by the reactive subspecie to form the electrolyte structure, immiscible in the solvent, that conforms around the three-dimensional surface of the anode; and   wherein, in the fourth form, the first proportion of the monomer transports solvated ions, via the network of open-cell pores of the electrolyte structure, between the anode and a cathode coupled to the electrolyte structure opposite the anode.   
     
     
         6 . The composition of  claim 4 :
 wherein, in the second form:
 the photoinitiator is dissociated into the reactive subspecie by exposure to electromagnetic radiation; and 
 the polymer phase-separates from the monomer, crosslinked by the reactive subspecie, and entangles to form a colloidal suspension throughout the electrolyte structure; and 
   wherein, in the third form, the second proportion of the polymer in the colloidal suspension is dissolved out of the electrolyte structure to render the network of open-cell pores characterized by an average cross-sectional width greater than an average width of solvated ions in the electrolyte structure.   
     
     
         7 . The composition of  claim 4 :
 wherein, in the second form:
 the first proportion of the monomer comprises between 55% and 65% by volume of the monomer comprising an epoxy-based photoresist; and 
 the second proportion of the polymer comprises between 35% and 45% by volume of the polymer comprising a synthetic polymer of an organic compound; and 
   wherein, in the third form, the second proportion of the polymer is dissolved out of the electrolyte structure by the solvent to render an open pore volume between 35% and 45% in the electrolyte structure.   
     
     
         8 . The composition of  claim 1 :
 wherein, in the first form, the first proportion of the monomer and the second proportion of the polymer are mixed with a third proportion of the solvent to form an homogenous mixture of a first viscosity;   wherein, in the second form, the first proportion of the monomer is crosslinked by the reactive subspecie to form the electrolyte structure of a second viscosity over an anode, the second viscosity greater than the first viscosity; and   comprising, in a third mode, the first proportion of the monomer and the second proportion of the polymer wetted by a fourth proportion of the solvent less than the third proportion of the solvent.   
     
     
         9 . The composition of  claim 1 :
 wherein, in the first form, the third proportion of the solvent comprises approximately 50% by weight of a volatile liquid; and   wherein, in the third form, the fourth proportion of the solvent comprises less than 10% by weight of the volatile liquid.   
     
     
         10 . The composition of  claim 1 :
 wherein, in the first form, the first proportion of the monomer, the second proportion of the polymer, and the photoinitiator are dissolved in the solvent and deposited over an anode defining a three-dimensional surface; and   wherein, in the second form:
 the photoinitiator is dissociated into the reactive subspecie by exposure to electromagnetic radiation; 
 the reactive subspecie locally crosslinks the monomer to form the electrolyte structure conforming around the three-dimensional surface of the anode; and 
 the polymer phase-separates from the monomer, crosslinked by the reactive subspecie, and entangles to form an unlinked network throughout the electrolyte structure. 
   
     
     
         11 . The composition of  claim 1 :
 wherein, in the second form, the photoinitiator locally dissociates into the reactive subspecie responsive to incident electromagnetic radiation at a first wavelength;   wherein, in the first form, the first proportion of the monomer comprises the monomer characterized by a first molar mass, a first dimension less than the first wavelength, and a first index of refraction at the first wavelength; and   wherein, in the first form and the second form, the second proportion of the polymer comprises the polymer characterized by a second average molar mass approximating the first molar mass, a second average dimension less than the first wavelength, and a second index of refraction at the first wavelength approximating the first index of refraction.   
     
     
         12 . An electrolyte material comprising:
 in a first form:
 a first proportion of a monomer miscible in a solvent; 
 a second proportion of a polymer semi-miscible in the monomer and miscible in the solvent; and 
 a photoinitiator configured to disassociate into a reactive subspecie responsive to exposure to electromagnetic radiation, the reactive subspecie configured to crosslink the monomer; and 
   wherein, in a second form following application onto a substrate and exposure to electromagnetic radiation:
 the first proportion of the monomer is crosslinked by the reactive subspecie of the photoinitiator to form an electrolyte structure immiscible in the solvent; and 
 the second proportion of the polymer is miscible in the solvent and phase-separated from the crosslinked monomer that forms the electrolyte structure. 
   
     
     
         13 . The electrolyte material of  claim 12 :
 wherein, in a third form, the second proportion of the polymer is dissolved out of the electrolyte structure by the solvent to render a network of open-cell pores in the electrolyte structure; and   wherein, in a fourth form, the first proportion of the monomer is crosslinked by the reactive subspecie of the photoinitiator to define the electrolyte structure comprising the network of open-cell pores filled with a volume of solvated ions to form an electrolyte.   
     
     
         14 . The composition of  claim 13 :
 wherein, in the first form, the first proportion of the monomer, the second proportion of the polymer, and the photoinitiator are dissolved in the solvent and deposited over an anode defining a three-dimensional surface;   wherein, in the second form and the third form, the first proportion of the monomer is crosslinked by the reactive subspecie to form the electrolyte structure, immiscible in the solvent, that conforms around the three-dimensional surface of the anode; and   wherein, in the fourth form, the first proportion of the monomer transports solvated ions, via the network of open-cell pores of the electrolyte structure, between the anode and a cathode coupled to the electrolyte structure opposite the anode.   
     
     
         15 . The composition of  claim 14 :
 wherein, in the first form:
 the first proportion of the monomer comprises monomers of bisphenol a novolac epoxy miscible in the solvent comprising a volatile liquid; and 
 the second proportion of the polymer comprises a blend of Poly(methyl methacrylate) molecules within a first narrow range of molecular weights and Poly(methyl methacrylate) molecules within a second narrow range of molecular weights greater than the first narrow range of molecular weights; 
   wherein, in the first form, the first proportion of the monomer, the second proportion of the polymer, and the photoinitiator are deposited over the anode comprising a silicon substrate; and   wherein, in the fourth form, the first proportion of the monomer defines the electrolyte structure comprising the network of open-cell pores filled with the volume of solvated lithium ions to form the electrolyte.   
     
     
         16 . A method for fabricating an electrolyte comprising:
 depositing an electrolyte material over a substrate, the electrolyte material comprising a monomer miscible in a first volume of solvent, a polymer semi-miscible in the monomer and miscible in the first volume of solvent, and a photoinitiator;   during a first period of time:
 heating the electrolyte to promote phase-separation of the polymer from the monomer and cluster of the polymer into an unlinked polymer network; and 
 cooling the electrolyte material and the substrate to reduce mobility of the unlinked polymer network in the monomer; 
   during a second period of time succeeding the first period of time, exposing the electrolyte material to electromagnetic radiation to disassociate the photoinitiator into a reactive subspecie that crosslinks the monomer to form an electrolyte structure with the polymer phase-separated from the electrolyte structure;   dissolving the polymer out of the electrolyte structure with a second volume of solvent to render a network of open-cell pores in the electrolyte structure; and   exposing the electrolyte structure to a third volume of solvent and ions to fill the network of open-cell pores with solvated ions.   
     
     
         17 . The method of  claim 16 :
 wherein depositing the electrolyte material over the substrate comprises depositing the electrolyte material over the substrate comprising an anode;   further comprising depositing a cathode material over the electrolyte structure opposite the anode, the cathode material comprising ion-storing material; and   wherein exposing the electrolyte structure to the third volume of solvent and ions comprises wetting the cathode material with the third volume of solvent to draw solvated ions from the cathode material into the network of open-cell pores in the electrolyte structure.   
     
     
         18 . The method of  claim 16 :
 further comprising etching the substrate to form a cell comprising:
 a base encompassed by a wall; and 
 a set of posts extending from the base; 
   wherein depositing the electrolyte material over the substrate comprises depositing the electrolyte material into the cell and around the set of posts in the cell; and   wherein exposing the electrolyte material to electromagnetic radiation comprises exposing the electrolyte material to electromagnetic radiation to crosslink the monomer into a thin-shell electrolyte structure around the continuous wall and the set of posts within the cell.   
     
     
         19 . The method of  claim 16 :
 wherein depositing the electrolyte material over the substrate comprises depositing the electrolyte material comprising a first proportion of the monomer and a second proportion of the polymer dissolved in the first volume of solvent; and   wherein dissolving the polymer out of the electrolyte structure comprises rinsing the electrolyte structure with the second volume of solvent to render approximately the second proportion of open-cell volume in the electrolyte structure.   
     
     
         20 . The method of  claim 19 :
 wherein depositing the electrolyte material over the substrate comprises depositing the electrolyte material:
 comprising between 55% and 65% by volume of the monomer comprising an epoxy-based negative photoresist; 
 comprising between 35% and 45% by volume of the polymer comprising a synthetic polymer of an organic compound; and 
 dissolved in the first volume of solvent comprising a volatile liquid; and 
   wherein dissolving the polymer out of the electrolyte structure comprises rinsing the electrolyte structure with the volatile liquid to dissolve the polymer out of the electrolyte structure.   
     
     
         21 . The method of  claim 16 :
 wherein depositing the electrolyte material over the substrate comprises doctor-blading the electrolyte material over the substrate; and   further comprising, after exposing the electrolyte material to electromagnetic radiation during the second period of time, heating the electrolyte material to crosslink monomers in local volumes of the electrolyte material containing the reactive subspecie generated by the photoinitiator responsive to exposure to electromagnetic radiation.