All-inorganic solvents for electrolytes

A rechargeable battery, comprising:

• a cathode;
• an anode comprising lithium;
• and
• an electrolyte solution, comprising:
• an electrolyte solvent comprising a cyclic phosphazene compound present in an amount of between 0.1% and 50% by volume, wherein the electrolyte solvent remains liquid at 0° C. and is stable at 5 V;
• and
• a lithium salt dissolved in the electrolyte solvent at a concentration of between 0.1 to 5 M, to achieve a conductivity of at least 0.9 mS/cm,
• the electrolyte solution comprising less than about 2% purely organic compounds consisting essentially of carbon, hydrogen and oxygen, and having a flash point above 60.6° C.,
• wherein the cyclic phosphazene compound is a hexasubstituted triazatriphosphinine with substituents independently selected from the group consisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substituted alkyl, halogen substituted aryl, halogen substituted heteroalkyl, halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy, heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy, halogen substituted heteroalkoxy, and halogen substituted heteroaryloxy functional groups.

A rechargeable battery, comprising:

• an anode comprising lithium;
• a cathode;
• an electrolyte solution stable at 5 V, comprising:
• a solvent having less than about 2% purely organic compounds consisting essentially of carbon, hydrogen and oxygen, comprising:
• at least one phosphoranimine compound in an amount of 20% to 80% by volume,
• at least one cyclic phosphazene compound present in an amount of between 0.1% and 50% by volume, and
• at least one monomeric phosphorus compound in an amount of 10% to 80% by volume,
• wherein the electrolyte solution has a melting point below 0° C., a viscosity of ≤30 cp at 35° C., and a flash point above 60.6° C.;
• and
• a lithium salt dissolved in the solvent at a concentration of between 0.1 M and 5 M, sufficient to achieve a conductivity of at least 0.9 mS/cm;
• and
• a solid electrolyte interphase layer on the cathode,
• wherein the phosphoranimine compound has a chemical structure X—N═P(R1,R2,R3), where X is selected from the group consisting of organosilyl, alkyl, and aryl, and each of R1, R2, and R3 is selected from the group consisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substituted alkyl, halogen substituted aryl, halogen substituted heteroalkyl, halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy, heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy, halogen substituted heteroalkoxy, and halogen substituted heteroaryloxy functional groups,
• wherein the cyclic phosphazene compound is a hexasubstituted triazatriphosphinine with substituents independently selected from the group consisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substituted alkyl, halogen substituted aryl, halogen substituted heteroalkyl, halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy, heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy, halogen substituted heteroalkoxy, and halogen substituted heteroaryloxy functional groups, and
• wherein the at least one monomeric phosphorus compound is selected from the group consisting of a phosphate, phosphonate, phosphinate, phosphine, and a phosphine oxide, having at least two different pendent groups independently selected from the group consisting of alkyl, aryl, heteroalkyl, heteroaryl, halogen substituted alkyl, halogen substituted aryl, halogen substituted heteroalkyl, halogen substituted heteroaryl, alkoxy, aryloxy, heteroalkoxy, heteroaryloxy, halogen substituted alkoxy, halogen substituted aryloxy, halogen substituted heteroalkoxy, and halogen substituted heteroaryloxy functional groups.