Reactive sintering of ceramic lithium-ion solid electrolytes

Abstract

A method of forming a solid, dense, hermetic lithium-ion electrolyte membrane comprises combing an amorphous, glassy, or low melting temperature solid reactant with a refractory oxide reactant to form a mixture, casting the mixture to form a green body, and sintering the green body to form a solid membrane. The resulting electrolyte membranes can be incorporated into lithium-ion batteries.

What is claimed is: 
     
         1 . A solid lithium-ion electrolyte membrane having a composition represented by the formula Li 1+x−y M x M′ 2-x-y M″ y (PO 4 ) 3 , wherein M is a 3 +  ion, M′ is a 4 +  ion, M″ is a 5 +  ion, 0≤x≤2 and 0≤y≤2. 
     
     
         2 . The electrolyte membrane according to  claim 1 , wherein M is Al or Fe, M′ is selected from the group consisting of Ti, Sn, Nb and Ge, and M″ is Nb. 
     
     
         3 . The electrolyte membrane according to  claim 1 , wherein a thickness of the membrane is less than 200 microns. 
     
     
         4 . The electrolyte membrane according to  claim 1 , wherein a conductivity of the membrane is greater than 10 −4  S/cm. 
     
     
         5 . The electrolyte membrane according to  claim 1 , wherein a density of the membrane is at least 95% of its theoretical density. 
     
     
         6 . A solid electrolyte membrane comprising a sintered reaction product of a first powder and a second powder, wherein
 the first powder comprises a first inorganic, non-lithium-ion-conductive glass or ceramic, and   the second powder comprises a second inorganic, non-lithium-ion-conductive glass or ceramic.   
     
     
         7 . The solid electrolyte membrane according to  claim 6 , wherein the first powder comprises a material selected from the group consisting of lithium phosphate glasses, germanium phosphate glasses, lithium aluminum phosphate glasses and crystallized lithium aluminum phosphate ceramics and the second powder comprises a material selected from the group consisting of titanium oxide, tin oxide and germanium oxide.