Aprotic polymer/molten salt ternary mixture solvent, method for the production and use thereof in electrochemical systems

Abstract

The invention relates to an aprotic polymer/molten salt ternary mixture solvent and to a corresponding quaternary mixture additionally comprising an ionic conducting salt, which are prepared by mixing the constituents of the mixture. These mixtures are advantageously used in the preparation of electrochemical membranes, electrochemical systems and of electrochromic systems. The invention also relates to electrochemical and electrochromic systems obtained hereby that exhibit, in particular, excellent electrochemical properties at low temperatures.

1 . Aprotic polymeric ternary mixture-molten salt-solvent (PSS) ternary mixture, wherein the aprotic polymer is selected from the group constituted by aprotic polymers and mixtures of at least two of the latter, and by polymer mixtures including at least 20% by weight of an aprotic polymer. 
     
     
         2 . Ternary mixture according to  claim 1 , homogenous and liquid at room temperature, wherein the aprotic polymer has a mean molecular weight (MW) between 1,000 and 1,000,000. 
     
     
         3 . Ternary mixture according to  claim 1 , presenting a transparency over 80%, wherein said transparency being measured using a UV-IR type near IR Variant brand device, a 2 mm thick mineral glass plate as reference of 100% transparency and a sample to measure constituted:
 in the case where a cross-linkable aprotic polymer is present in the ternary mixture, by a solid room temperature film with a thickness ranging from 20 to 100 microns, wherein said film being obtained by coating and cross-linking of said ternary mixture; or   in the case where no cross-linkable aprotic polymer is present in the ternary mixture, by a gel film of the ternary mixture, with a thickness ranging from 10 to 30 microns, wherein said gel being applied between two transparent glass plates.   
     
     
         4 . Ternary mixture according to  claim 3 , presenting a transparency over 90%. 
     
     
         5 . Ternary mixture according to  claim 1 , wherein the aprotic polymer is cross-linkable. 
     
     
         6 . Ternary mixture according to  claim 5 , wherein the polymer presents a percentage of cross-linkable bonds over 80%. 
     
     
         7 . Ternary mixture according to  claim 6  wherein the percentage of cross-linking is comprised between 5 and 50%. 
     
     
         8 . Ternary mixture according to  claim 7 , wherein the percentage of cross-linkable bonds is comprised between 10 and 30%. 
     
     
         9 . Ternary mixture according to  claim 5 , wherein the cross-linkable polymer is selected from the group constituted by the polymers of the type 3-branch polyether, 4-branch polyether, GE vinyl and by the mixtures of at least two of these polymers. 
     
     
         10 . Ternary mixture according to  claim 1 , wherein the polymer is non-cross-linkable. 
     
     
         11 . Ternary mixture according to  claim 10 , wherein the non-cross-linkable aprotic polymer is selected from the group constituted by the polymers of the type polyvinyidienefluoride (PVDF) and poly(methylmethacrylate) PMMA, and by the mixtures of at least two of the latter. 
     
     
         12 . Ternary mixture according to  claim 1 , wherein the aprotic polymer is constituted by a mixture of at least one cross-linkable polymer and at least one non cross-linkable polymer. 
     
     
         13 . Ternary mixture according to  claim 12 , wherein the polymer mixture, crosslinkable polymer includes at least one PMMA. 
     
     
         14 . Ternary mixture according to  claim 1 , wherein the molten salt present in the ternary mixture is selected amongst those melted at a temperature comprised between −40 and 350° C. 
     
     
         15 . Ternary mixture according to  claim 14 , wherein the molten salt present in the ternary mixture is selected amongst those melted at a temperature comprised between −20 and 60° C. 
     
     
         16 . Ternary mixture according to  claim 1 , containing at least two salts selected from the group constituted by imidazolium, imidinium, pyridinium, ammonium, pyrolium, sulfonium and phosphonium salts and by the mixtures of at least two of the latter. 
     
     
         17 . Ternary mixture according to  claim 16 , wherein the molten salts are selected from the group constituted by the soluble hydrophobic salts described in  claim 16 , as well as by the mixtures of at least two of the latter. 
     
     
         18 . Ternary mixture according to  claim 1 , wherein the solvent present in the ternary mixture is selected from the group constituted by organic solvents of the type EC, PC, DMC, DEC, EMC, GBL, VC, VB and by the mixtures of at least two of the latter. 
     
     
         19 . Ternary mixture according to  claim 1 , wherein the solvent present in the ternary mixture is selected from the group constituted by inorganic solvents of the type KOH, NaOH and by the mixtures of at least two of the latter. 
     
     
         20 . Ternary mixture according to  claim 1 , constituted by a mixture of an organic and an inorganic solvent. 
     
     
         21 . Ternary mixture according to  claim 18 , wherein the solvent is of the organic type and presents a boiling point over 125° C. in standard temperature and pressure conditions. 
     
     
         22 . Ternary mixture according to  claim 1 , containing by weight:
 from 5 to 70 mole percent of aprotic polymer;   from 5 to 70 mole percent of molten salt; and   from 7 to 70 mole percent of solvent, the total weight of the constituents of the ternary mixture being equal to 100%   
     
     
         23 . Ternary mixture according to  claim 22 , characterized by a viscosity varying from 1 to 5000 cP. 
     
     
         24 . Quaternary mixture comprising a ternary mixture according to  claim 1  and an ion-conducting salt. 
     
     
         25 . Quaternary mixture according to  claim 24 , wherein the ion-conducting salt is of the type LiTFSl, LiFS1, LiBOB, LiDCTA, LiC1O 4 , LiCF 3 S0 3 , LiPF 6 , LiBF 4 , Lil and by the mixtures of at least two of the latter. 
     
     
         26 . Quaternary mixture according to  claim 24 , wherein the concentration of ion-conducting salt varies from 0.01 to 3M (M: molar). 
     
     
         27 . Quaternary mixture according to  claim 26 , wherein the concentration of conducting salt varies from 0.5 M to 2.5 M. 
     
     
         28 . Quaternary mixture according to  claim 24 , wherein the aprotic polymer is cross-linkable by any one of the following methods: UV, IR, thermal and Ebeam. 
     
     
         29 . Quaternary mixture according to  claim 24 , containing by weight:
 a. from 5 to 70 mole percent of polymer;   b. from 5 to 70 mole percent of molten salt;   c. from 7 to 70 mole percent of solvent; and   d. from 7 to 70 mole percent of ion conducting salt, the total weight of the constituents of the quaternary mixture being equal to 100%.   
     
     
         30 . Quaternary mixture according to  claim 24 , characterized by a viscosity varying from 1 to 5,000 cP. 
     
     
         31 . Ternary mixture according to  claim 1 , wherein the aprotic polymer is cross-linkable by at least one of the following methods: UV, IR, thermal, Ebeam. 
     
     
         32 . Preparation process of a ternary mixture comprising mixing, in an indifferent order, the constituents of ternary mixture of  claim 1 . 
     
     
         33 . Preparation process according to  claim 32 , comprising mixing the constituents in one step at a controlled pressure and under inert atmosphere. 
     
     
         34 . Preparation process of an electrochemcial membrane comprising coating the ternary mixture of  claim 1  on a support. 
     
     
         35 . Preparation process of an electrochemical device comprising:
 forming a Polymer membrane from the ternary mixture of  claim 1 , and   abutting the polymer membrane against an electrode,   
       wherein the polymer membrane is of the non-salted type, and it is soaked in a salted SS (solvent-molten salt) mixture after abutment against one of the electrodes. 
     
     
         36 . Preparation process of an electrochemical device comprising:
 forming a polymer membrane from the ternary mixture of  claim 1 , and   abutting the polymer membrane against an electrode,   
       wherein the polymer membrane is of the non-salted type, and it is soaked in a non-salted SS mixture after abutment against one of the electrodes. 
     
     
         37 . Preparation process of an electrochemical device comprising:
 forming a polymer membrane from the ternary mixture of  claim 1 , and   abutting the polymer membrane against an electrode,   wherein the polymer membrane is of the salted type, and it is soaked in a salted SS mixture after abutment against one of the electrodes.   
     
     
         38 . Preparation process of an electrochemical device comprising:
 forming a polymer membrane from the ternary mixture of  claim 1 , and   abutting the polymer membrane against an electrode,   
       wherein the polymer membrane is of the salted type and is soaked in a nonsalted SS mixture after abutment against one of the electrodes. 
     
     
         39 . Preparation process of an electrochemical membrane according to  claim 34 , further comprising an ion-conducting salt dissolved in the molten salt of the ternary mixture. 
     
     
         40 . Preparation process of an electrochemical membrane according to  claim 34 , further comprising an ion-conducting salt dissolved in the solvent of the ternary mixture. 
     
     
         41 . Preparation process of an electrochemical device according to  claim 35 , wherein the membrane is abutted against the electrode and adheres to it. 
     
     
         42 . Preparation process of an electrochemical system comprising at least two electrodes and at least one electrolyte constituted from a PSS ternary mixture and/or from a PSSS mixture. 
     
     
         43 . Preparation process of an electrochemical system comprising at least one electrode, at least one cathode, at least one electrolyte (PSS). 
     
     
         44 . Preparation process of an electrochemical system wherein the system comprises an electrochromic window. 
     
     
         45 . Preparation process of an electrochemical system according to  claim 44 , said electrochemical system comprising at least one intercalation electrode and at least one double layer electrode. 
     
     
         46 . Preparation process of an electrochemical system according to  claim 42 , wherein the ternary mixture is constituted by the 4-branch polymer Elexce10-PA-210, molten salt (propylmethylimidazol+1 M LiTFS1.) and solvent (VC: vinyl carbonate). 
     
     
         47 . Preparation process of an electrochemical device, comprising:
 a solid transparent substrate;   a transparent oxide film;   a PSS and/or PSSS film;   a counter electrode; and   a sealer   
       by implementing the following steps:
 preparation of a solid transparent substrate having a transparent conducting layer; 
 preparation of a transparent and conducting oxide based cathode; 
 preparation of a PSS-type and/or PSSS-type transparent electrolyte presenting a transparency over 80%; 
 preparation of an anode (counter electrode) based on a transparent oxide, on a conducting polymer or on a carbon on a solid transparent substrate having a transparent conducting layer; 
 assembly of the hereinbefore prepared elements; and 
 sealing of the extremities (perimeters) of the substrates with a sealer. 
 
     
     
         48 . Process according to  claim 47 , for preparing an electrochromic window with a transparent electrolyte of the PSS type presenting a transparency over 80%. 
     
     
         49 . Preparation process of an electrochromic device according to  claim 47 , wherein a aprotic polymeric ternary mixture-molten salt-solvent (PSS) ternary mixture is coated on one of the electrodes and after abutment on the other electrode, wherein the aprotic Polymer is selected from the group constituted by aprotic polymers and mixtures of at least two of the latter, and by polymer mixtures including at least 20% by weight of an aprotic Polymer. 
     
     
         50 . Preparation process of an electrochromic device according to  claim 47 , wherein the cathode is based on a metal oxide selected from the group constituted by: W0 3 , MoO 3 , V 2 0 5 , Li 4 Ti 5 0 12  and electronic conducting polymer and by the mixtures of at least two of the latter. 
     
     
         51 . Preparation process of an electrochromic device according to  claim 47 , wherein the anode is based on a metal oxide selected from the group constituted by: IrOx, LiVOx, NiOx, NiOxHy (with x comprised between 00.1 and 0.2), Ta 2 0 5 , Sb 2 0 5 , the electrically conducting polymers and by the mixtures of at least two of the latter. 
     
     
         52 . Preparation process of an electrochromic device according to  claim 47 , wherein the PSS mixture is introduced into the device at the level of the space separating the two electrodes, this space corresponding to a distance between electrodes varying between 5 and 500 microns. 
     
     
         53 . Preparation process of an electrochromic device according to  claim 52 , wherein said device is heated to temperatures varying from 25 to 100° C., for 1 hour to allow the cross-linking of the polymer. 
     
     
         54 . Preparation process of an electrochromic device according to  claim 51 , wherein said device contains a polymer membrane between the two electrodes and the SS mixture is introduced into the sealed electrochemical device. 
     
     
         55 . Electrochromic device obtained by implementation of a process as defined in  claim 47 . 
     
     
         56 . Electrochemical device characterized by a high yield at low temperature. 
     
     
         57 . Electrochemical device characterized by a yield at −20° C. corresponding to at least 80% of the electrochemical yield obtained for the same device at room temperature. 
     
     
         58 . Preparation process of an electrochemical device according to  claim 47 , applied to the preparation of a battery-type generator the anode of which is selected from the group constituted by the electrodes of the type lithium, lithium alloy, carbon, graphite and metal oxide and the cathode of LiFePO 4 , LiCoO 2 , LiMn 2 O 4 , LiNiO 2 , LiMn 1/3  CO 1/3  Ni 1/3  0 2 , and by the mixtures of at least two of the latter. 
     
     
         59 . Use of a ternary or quaternary mixture as defined in  claim 1  in one of the following applications: electrolyte for electrochemical system, electrochromic window, and electrochemical generator. 
     
     
         60 . Electrochemical systems obtained by implementation of  claim 42 .