an organosilsesquioxane polymer precursor for the electrolyte element of the invention has the general formula : ## str1 ## wherein r and r &# 39 ; are the same or different radicals selected from the group consisting of aliphatics of 1 - 4 carbons , phenyl , phenyls substituted with one or more hydroxy or halogen , and halogens , provided r and r &# 39 ; are not both halogen ; x 1 , x 2 , x 3 , and x 4 are functional radicals selected from the group consisting of alkoxies of 1 - 4 carbons , halogens , hydroxyl , and silanol ; and n is an integer in the range of 10 - 200 . these &# 34 ; ladder &# 34 ; siloxane polymers are commercially prepared by hydrolysis and condensation polymerization of the appropriately substituted silanes . preparation of the electrolyte element begins with the formation of a solution of the selected ladder polymer in an organic solvent . this solution , adjusted as desired for viscosity and solids composition , is then cast as a coating by any common method , such as spinning , dipping , or the like , onto a selected substrate and dried . moderate heating in the range of about 150 °- 400 ° c ., depending upon the extent of time , cures the coating to a glass - like state that is insoluble in organic solvents . the ready formation of precursor polymer layers in this manner provides a particular advantage in allowing the precise positioning of electrolyte elements of minimal and consistent thickness in the final battery structure . coating upon a battery electrode component , for example , locates the electrolyte element in its desired position throughout battery assembly , thereby simplifying that operation and ensuring proper and secure element arrangement . the cured precursor polymer layer is then processed to remove the pendant radical groups and impart to the remaining silica layer an intricate network of minute voids , the sizes of which generally vary , down to about 10 nm , with the sizes of the respective radicals . this processing may comprise heating in air or oxygen in the range of 600 °- 1000 ° c ., but the deleterious effects of such temperatures are avoided and the processing made far more practical by the preferred barrel reactor plasma oxidation at room temperature . the fenestrated silica layer is then prepared for incorporation into a battery assembly by filling the voids network with the desired electrolyte solution , typically a lithium compound , such as liclo 4 , liasf 6 , lipf 6 , libf 4 , or lib ( c 6 h 5 ) 4 , in a suitable organic solvent . loading the electrolyte is simply a matter of application to the element surface where the solution is taken in by the natural capillarity of the dispersed voids network . completely filling the smallest voids may be facilitated by prior evacuation of the voids or application of the solution under pressure . once loaded into the voids matrix network , the electrolyte is substantially immobilized with little danger of leakage or migration within the finished battery assembly . a secondary battery 10 incorporating an electrolyte element of the invention is depicted in the drawing figure . this representative structure comprises positive electrode 19 which may be one of the many available intercalatable materials , for example tis 2 , tis x o y , or agmo 6 s 8 , which have been employed with lithium electrodes , or , preferably , one of the more functional lithiated ternary transition metal oxides , such as limn 2 o 4 , li 2 mn 2 o 4 , licoo 2 , or linio 2 . in intimate contact with electrode 19 , preferably as an attached coated layer previously described , is separator / electrolyte element 17 , the voids matrix of which contains the lithium ion electrolyte solution . negative electrode 15 pressed into firm contact with electrolyte element 17 by means of a swagelock or other compressive assembly device completes the basic battery assembly and may be any of the many known lithium ion sources , for example lithium metal , a lithium alloy , or , preferably , a lithium intercalatable material such as wo 2 , al , or carbon , which have been shown to be effective with the noted lithiated ternary oxide electrodes . collector plates 14 , 18 intimately contacting respective electrodes 15 , 19 provide means for attaching electrical conductors 16 through which current flows during the charge and discharge cycles of the battery . a preferred secondary battery embodying the present electrolyte element was constructed in the following manner . limn 2 o 4 powder , typically prepared by thermal reaction of lithium carbonate and manganese dioxide , was mixed with about one weight percent polytetrafluoroethylene binder and five percent super - s graphite for improved electrical conductivity . the resulting mixture was compressed to form an electrode wafer 19 about 0 . 8 mm thick . one face of the wafer was flow coated with an acetylnitrile solution of about 40 weight percent solid gr150 , a ladder siloxane commercially obtained from oi - neg and having methyl and phenyl pendant radicals . the pot - life of this coating solution was somewhat limited by its slow conversion to a viscous gel , a condition that appears to be accelerated by its hygroscopicity . the coating was thoroughly oven - dried at about 110 ° c . and then heated for an additional 30 minutes at about 220 ° c . to complete the curing of the coating to a glassy layer about 50 micrometers thick . the uncoated side of the electrode wafer was temporarily covered with a thin foil of aluminum to protect against oxidation of the limn 2 o 4 surface which could otherwise result in loss of contact conductivity . the assembly was placed in a barrel plasma oxidation reactor with the siloxane surface in position for exposure to the plasma . the siloxane layer was then oxidized at 13 . 56 mhz in pure oxygen at a pressure of about one millitor for about three hours during which time the methyl and phenyl radicals were removed from the silica backbone of the compound . this initially clear layer became opaquely white due to light scattering by the dispersed voids matrix formed as a result of removing the pendant radicals . a one molar electrolyte solution of liclo 4 in a mixture of equal parts of diethylene carbonate and diethoxyethane was applied at ambient conditions to the silica layer surface and after a few minutes the surface was blotted dry of excess solution . a decrease in the whiteness of the silica layer evidenced the infusion of electrolyte into the voids matrix . a wafer 15 of graphite about 0 . 7 mm thick was then positioned on the silica layer separator / electrolyte element 17 to serve as the negative electrode of the battery assembly . stainless steel contact plates 14 , 18 were placed in intimate contact with the exposed surfaces of electrodes 15 , 19 and the assembly was compressed in a swagelock test cell to form battery 10 . the battery was then charged through conductors 16 during which operation lithium ions migrated through electrolyte element 17 from limn 2 o 4 electrode 19 to intercalate graphite electrode 15 which thereafter served as the negative electrode lithium ion source upon discharge of the battery . charging was discontinued at a predetermined limit of about 4 . 5 v to prevent decomposition of the electrolyte solvent . the battery was then continually operated through discharge / charge cycles for several weeks . at the conclusion of this test period , the battery was disassembled in order to examine electrolyte element 17 which appeared to be intact with no discernible loss or leakage of electrolyte solution . the utility of the present electrolyte elements in secondary lithium batteries with all manner of electrode combinations , whether including lithium metal or alloys , or the more environmentally preferred intercalation electrodes , provides the means for safer and more economical supplies of these important energy sources . in addition to the suggested variations in electrode combinations and electrolyte element composition and processing , it is anticipated that other embodiments of the present invention will undoubtedly occur to the skilled artisan in the light of the foregoing description . such embodiments are likewise intended to be encompassed within the scope of the invention as recited in the following claims .