Use of a ceramic separator in lithium-ion batteries comprising an electrolyte comprising ionic liquids

Abstract

The invention relates to a separator filled with an electrolyte composition, the separator having a ceramic surface and the electrolyte composition comprising an ionic liquid. The filling with the electrolyte composition can be effected for example by utilizing the separator in a battery, for example a lithium-ion battery, which has been filled with an appropriate electrolyte composition.

1 - 3 . (canceled) 
     
     
         4 . A separator comprising a sheetlike flexible substrate which has a multiplicity of openings and a coating present on and in this substrate, the material of the substrate being selected from woven or non-woven nonelectroconductive polymeric or natural fibers and the coating being a porous electroinsulating ceramic coating, the separator being filled with an electrolyte composition, characterized in that the electrolyte composition comprises a conducting salt and a base component, the main constituent of the base component, at a fraction of greater than 50% by mass, being at least one ionic liquid having a melting point of less than 100° C. 
     
     
         5 . A separator according to  claim 4 , characterized in that the flexible substrate of the separator is a nonwoven, the material of the nonwoven being selected from non-woven nonelectroconductive polymeric fibers. 
     
     
         6 . A separator according to  claim 5 , wherein the nonwoven from a polymeric or natural fiber has a thickness of less than 30 μm, a porosity of more than 50% and a pore radius distribution where at least 50% of the pores have a pore radius in the range from 75 to 150 μm. 
     
     
         7 . A separator according to  claim 4 , characterized in that the substrate comprises polymeric fibers selected from fibers of polyacrylonitrile, polyamides, polyimides, polyacrylates, polytetrafluoroethylene, polyester and/or polyolefin. 
     
     
         8 . A separator according to  claim 7 , wherein the polymeric fibers are 0.1 to 10 μm in diameter. 
     
     
         9 . A separator according to  claim 4 , wherein the substrate is a flexible nonwoven from a polymeric or natural fiber, said nonwoven having a basis weight, said basis weight being less than 20 g/m 2 . 
     
     
         10 . A separator according to  claim 4 , wherein the substrate is 5 to 30 μm in thickness. 
     
     
         11 . A separator according to  claim 4 , wherein the substrate has a porosity of from 50% to 97%. 
     
     
         12 . A separator according to  claim 4 , wherein the coating present on and in the substrate comprises an oxide, nitride or carbide of at least one metal selected from the group consisting of Al, Zr, Si, Sn, Ce, and Y. 
     
     
         13 . A separator according to  claim 4 , wherein the porous ceramic coating present on and in the substrate comprises oxide particles of Al, Si, Zr, or a combination thereof, the oxide particles having an average particle size of from 0.1 to 7 μm. 
     
     
         14 . A separator according to  claim 4 , wherein the porous ceramic coating present on and in the substrate comprises alumina particles having an average particle size of from 0.5 to 5 μm which are adhered together by an oxide of Zr or Si. 
     
     
         15 . A separator according to  claim 4 , wherein the separator is less than 50 μm in thickness. 
     
     
         16 . A separator according to  claim 4 , wherein the separator is bendable without damage down to a radius down to 100 mm. 
     
     
         17 . A separator according to  claim 4 , wherein the ceramic coating has present thereon a porous shutdown layer of a material which melts at a predetermined temperature and closes the pores in the ceramic layer, and wherein the shutdown layer comprises at least one porous sheetlike structure selected from the group consisting of a woven fabric, a nonwoven fabric, a felt fabric, a loop-formingly knitted fabric, a porous film, a porous sheet, and a porous foil. 
     
     
         18 . A separator according to  claim 17 , wherein the shutdown layer is 1 to 20 μm in thickness. 
     
     
         19 . A separator according to  claim 17 , wherein the shutdown layer consists of a material selected from polymers, polymer blends, natural or artificial waxes or mixtures thereof, which has a melting temperature of less than 130° C. 
     
     
         20 . A separator according to  claim 4 , wherein the ionic liquid comprises at least one salt which has an ammonium, pyridinium, pyrrolidinium, pyrrolium, oxazolium, oxazolinium, imidazolium or phosphonium cation. 
     
     
         21 . A separator according to  claim 4 , wherein the electrolyte composition comprises
 a base component comprising
 80 to 99.5 parts by mass of at least one ionic liquid (A) which has a melting point of less than 100° C., 
 0.5 to 20 parts by mass of a film former (B) and 
 0 to 19 parts by mass of a viscosity modifier (C) and a conducting salt (D), 
   wherein a fraction of conducting salt (D) in the electrolyte composition is from 0.25 mol/kg up to the solubility limit of the conducting salt in the base component, based on the base component.   
     
     
         22 . A separator according to  claim 4 , satisfying at least one of the following conditions:
 the conducting salt is a lithium compound,   the film former (B) is an organic carbonate compound, and   the viscosity modifier is an organic aprotic solvent.   
     
     
         23 . A process for producing a separator according to  claim 4 , comprising
 providing a sheetlike flexible substrate which has a multiplicity of openings,   providing a coating in an on the substrate by applying a suspension which comprises particles of at least one inorganic compound suspended in a sol to the substrate and heating to solidify the suspension on and in the substrate, and   impregnating the thus prepared coating substrate with an electrolyte composition comprising a conducting salt and a base component, wherein the main constituent of the base component, at a fraction of greater than 50% by mass being at least one ionic liquid having a melting point of less than 100° C.   
     
     
         24 . A process according to  claim 23 , wherein impregnating is carried out at room temperature. 
     
     
         25 . A process for producing a lithium-ion battery, comprising
 installing a separator according to  claim 4  into a battery and filling the batter with an electrolyte, wherein the separation is impregnated with the electrolyte composition.   
     
     
         26 . A lithium-ion battery comprising a separator according to  claim 4 . 
     
     
         27 . A method of making a filled separator operable for a lithium-metal or lithium-ion battery, comprising filling a separator of  claim 4 , comprising filling the separator with an electrolyte composition, and installing a filled separator in a lithium-metal or lithium-ion battery.