Anodically stable and highly conducting borane solid state battery electrolytes

1 . An electrolyte comprising:

a composite salt mixture comprising:

a plurality of boron cluster salts comprising a halogenated boron cluster salt with a cation and a halogenated boron cluster anion, the cation selected from the group consisting of Li + , Na + , Mg 2+ , Ca 2+ , Zn 2+ and Al 3+ , and the halogenated boron cluster anion having a structure of:

[CB (y−1) H (y−z−i) R z X i ] − , [C 2 B (y−2) H (y−t−j−1) R t X j ] − , [C 2 B (y−3) H (y−t−j) R i X j ] − , [C 2 B (y−3) H (y−t−j−1) R t X j ] 2− , [C 2 B (y−4) H (y−t−j−1) R t X j ] 2− , [CB (y−1) H (y−z) R z ] − , [C 2 B (y−2) H (y−t−1) R t ] − , [C 2 B (y−3) H (y−t) R t ] − , [C 2 B (y−3) H (y−t−1) R t ] 2− , and/or B y H (y−z−i) R z X i ] 2− , wherein:

y is an integer within a range of 6 to 12;

(z+i) is an integer within a range of 0 to y;

(t+j) is an integer within a range of 0 to (y−1);

X is F, Cl, Br, or I; and

R is:

 (i) a linear, branched-chain, or cyclic C1-C18 alkyl or fluoroalkyl group;

 (ii) a C6-C9 aryl or fluoroaryl group;

 (iii) a linear, branched-chain, or cyclic C1-C8 alkoxy or fluoroalkoxy group;

 (iv) a C6-C9 aryloxy or fluoroaryloxy group;

 (v) amino; and

 (vi) a substituent that combines two or more of (i)-(v);

wherein at least 90 mol % of the boron cluster salts comprise a halogen atom.

2 . The electrolyte according to claim 1 , wherein X is directly bonded to a boron cluster atom or carbon cluster atom of the halogenated boron cluster anion structure.

3 . The electrolyte according to claim 1 , wherein at least 90 mol % of the boron cluster salts comprise a single halogen atom.

4 . The electrolyte according to claim 3 , wherein at least 1 mol % of the boron cluster salts comprise two halogen atoms.

5 . The electrolyte according to claim 1 , wherein is less than 10 mol % of the boron cluster salts comprise a single halogen atom.

6 . The electrolyte according to claim 5 , wherein at least 30 mol % of the boron cluster salts comprise two halogen atoms and at least 30 mol % of the boron cluster salts comprise three halogen atoms.

7 . The electrolyte according to claim 6 , wherein at least 1 mol % of the boron cluster salts comprise four halogen atoms.

8 . The electrolyte according to claim 1 , wherein greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts comprise two halogen atoms.

9 . The electrolyte according to claim 1 , wherein greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts comprise three halogen atoms.

10 . The electrolyte according to claim 1 , wherein greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts comprise four halogen atoms.

11 . The electrolyte according to claim 1 , wherein greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts are non-halogenated.

12 . The electrolyte according to claim 1 , wherein an anodic stability of the composite salt mixture and/or the halogenated boron cluster salt is at least 10% greater than an anodic stability of a parent halogen-free boron cluster salt.

13 . The electrolyte according to claim 1 , wherein the composite salt mixture and/or the halogenated boron cluster salt comprises a phase transition temperature between a non-superionic conducting phase and a superionic conducting phase transition that is less than a non-superionic conducting phase to superionic conducting phase transition temperature of a parent halogen-free boron cluster salt.

14 . The electrolyte according to claim 13 , wherein the phase transition temperature of the composite salt mixture and/or the halogenated boron cluster salt is at least 20° C. less than the non-superionic conducting phase to superionic conducting phase transition temperature of the parent halogen-free boron cluster salt.

15 . The electrolyte according to claim 14 , wherein the phase transition temperature for the composite salt mixture and/or the halogenated boron cluster salt is at least 30° C. less than the non-superionic conducting phase to superionic conducting phase transition temperature of the parent halogen-free boron cluster salt.

16 . An electrolyte comprising:

a composite salt mixture comprising:

a plurality of boron cluster salts comprising a halogenated boron cluster salt with a cation and a halogenated boron cluster anion, the cation selected from the group consisting of Li + , Na + , Mg 2+ , Ca 2+ , Zn 2+ and Al 3+ , and the halogenated boron cluster anion having a structure of:

[CB (y−1) H (y−z−i) R z X i ] − , [C 2 B (y−2) H (y−t−j−1) R t X j ] − , [C 2 B (y−3) H (y−t−j) R i X j ] − , [C 2 B (y−3) H (y−t−j−1) R t X j ] 2− , [C 2 B (y−4) H (y−t−j−1) R t X j ] 2− , [CB (y−1) H (y−z) R z ] − , [C 2 B (y−2) H (y−t−1) R t ] − , [C 2 B (y−3) H (y−t) R t ] − , [C 2 B (y−3) H (y−t−1) R t ] 2− , or B y H (y−z−i) R z X i ] 2− , wherein:

y is an integer within a range of 6 to 12;

(z+i) is an integer within a range of 0 to y;

(t+j) is an integer within a range of 0 to (y−1);

X is F, Cl, Br, or I; and

R is:

 (i) a linear, branched-chain, or cyclic C1-C18 alkyl or fluoroalkyl group;

 (ii) a C6-C9 aryl or fluoroaryl group;

 (iii) a linear, branched-chain, or cyclic C1-C8 alkoxy or fluoroalkoxy group;

 (iv) a C6-C9 aryloxy or fluoroaryloxy group;

 (v) amino; and

 (vi) a substituent that combines two or more of (i)-(v);

wherein at least 90 mol % of the boron cluster salts comprise a single halogen atom.

17 . The electrolyte according to claim 16 , wherein an anodic stability of the composite salt mixture and/or the halogenated boron cluster salt is at least 10% greater than an anodic stability of a parent halogen-free boron cluster salt.

18 . The electrolyte according to claim 16 , wherein:

greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts are non-halogenated, and greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts comprise two halogen atoms;

greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts comprise three halogen atoms; and

greater than 0 mol % and less than or equal to 10 mol % of the boron cluster salts comprise four halogen atoms; or

any combination thereof.

19 . An electrochemical cell comprising:

an anode selected from the group consisting of an alkaline anode, an alkaline earth anode, an insertion anode, a conversion anode, and an organic anode;

a cathode selected from the group consisting of a metal halide cathode, an air cathode, an organic cathode, an insertion cathode, and a conversion cathode; and

an electrolyte with a composite salt mixture comprising:

a plurality of boron cluster salts comprising a halogenated boron cluster salt with a cation and a halogenated boron cluster anion, the cation selected from the group consisting of Li + , Na + , Mg 2+ , Ca 2+ , Zn 2+ and Al 3+ , and the halogenated boron cluster anion having a structure of:

[CB (y−1) H (y−z−i) R z X i ] − , [C 2 B (y−2) H (y−t−j−1) R t X j ] − , [C 2 B (y−3) H (y−t−j) R i X j ] − , [C 2 B (y−3) H (y−t−j−1) R t X j ] 2− , [C 2 B (y−4) H (y−t−j−1) R t X j ] 2− , [CB (y−1) H (y−z) R z ] − , [C 2 B (y−2) H (y−t−1) R t ] − , [C 2 B (y−3) H (y−t) R t ] − , [C 2 B (y−3) H (y−t−1) R t ] 2− , or B y H (y−z−i) R z X i ] 2− , wherein:

y is an integer within a range of 6 to 12;

(z+i) is an integer within a range of 0 to y;

(t+j) is an integer within a range of 0 to (y−1);

X is F, Cl, Br, or I; and

R is:

 (i) a linear, branched-chain, or cyclic C1-C18 alkyl or fluoroalkyl group;

 (ii) a C6-C9 aryl or fluoroaryl group;

 (iii) a linear, branched-chain, or cyclic C1-C8 alkoxy or fluoroalkoxy group;

 (iv) a C6-C9 aryloxy or fluoroaryloxy group;

 (v) amino; and

 (vi) a substituent that combines two or more of (i)-(v);

wherein less than 10 mol % of the boron cluster salts comprise a single halogen atom.

20 . The electrochemical cell according to claim 19 , at least 30 mol % of the boron cluster salts comprise two halogen atoms and at least 30 mol % of the boron cluster salts comprise three halogen atoms.