LITHIUM METAL BATTERY SOLVENT
An electrolyte composition comprising a fluoroamino solvent and a lithium salt comprised of boron dissolved in the fluoroamino solvent, the fluoroamino solvent being a fluoroacetamide or fluoroimide may be used as an electrolyte in a secondary battery. The electrolyte composition is useful for lithium ion batteries having an anode comprised of lithium metal and the electrolyte may be present in a lean amount.
1 . A composition comprising a fluoroamino solvent and a lithium salt comprised of boron dissolved in the fluoroamino solvent, the fluoroamino solvent being a fluoroacetamide or fluoroimide, wherein the fluoroamino solvent comprises 10% to 90% by volume of the solvent.
2 . The composition of claim 1 , wherein the fluoroamino solvent is comprised of a fluoracetamide represented by:
or fluoroimide represented by:
where each R 1 is F, H, or alkyl having 1 to 12 carbons with at least one R 1 being F and R 2 is an alkyl, alkenyl, substituted alkyl or substituted akenyl having 1 to 12 carbons.
3 . (canceled)
4 . The composition of claim 2 , wherein each R 1 is F.
5 . The composition of claim 2 , wherein at least one R 2 is cyclic, branched or linear or both R 2 s form a fused cyclic ring.
6 . (canceled)
7 . (canceled)
8 . (canceled)
9 . The composition of claim 1 further comprising a second solvent.
10 . The composition of claim 9 , wherein the second solvent is comprised of a linear or cyclic carbonate.
11 . A composition of claim 10 , wherein the second solvent is comprised of a cyclic carbonate.
12 . The composition of claim 10 , wherein the second solvent has at least one F.
13 . The composition of claim 10 , wherein the second solvent is comprised of one or more of methyl (2,2,2-trifluoroethyl) carbonate, ethylene carbonate, fluoroethylene carbonate, difluoroethylene carbonate, 4-(2,2,3,3,4,4,5,5,5-nonafluoropentyl)-1,3-dioxolan-2-one (NFPEC), and 4-((2,2,3,3-tetrafluoropropoxy)methyl)-1,3-dioxolan-2-one (HFEEC).
14 . (canceled)
15 . The composition of claim 1 , wherein the fluoroamino solvent comprises at least 50% by volume of the solvent.
16 . (canceled)
17 . The composition of claim 1 , wherein the lithium salt comprised of boron is comprised of at least one electron withdrawing group —F or —CF 3 bonded to the boron.
18 . The composition of claim 17 , wherein the lithium salt comprised of boron is comprised of one or more boron salts represented by:
where R 3 is a substituted or unsubstituted aliphatic group having from 1 to 20 carbon atoms.
19 . The composition of claim 18 , wherein at least two adjacent R 3 s are a substituted cyclic aliphatic group of 5 to 8 atoms.
20 . (canceled)
21 . (canceled)
22 . The composition of claim 18 , wherein there are at least two boron salts.
23 . The composition of claim 22 , wherein each of the boron salts has a fluoro group bonded to the boron.
24 . The composition of claim 23 , wherein at least one of the salts has at least two adjacent R 3 s that are a substituted cyclic aliphatic group of 5 to 8 atoms
25 . (canceled)
26 . (canceled)
27 . The composition of claim 22 , wherein one of the boron salts is one that has a cyclic substituted aliphatic group and it is present in an amount of least 50% by mole of the lithium salt comprised of boron in the composition.
28 . The composition of claim 27 , wherein the boron salt having the cyclic substituted aliphatic group is lithium difluoro(oxalato)borate or lithium bis(oxalato)borate and the other boron salt is lithium tetrafluoroborate.
29 . (canceled)
30 . (canceled)
31 . A secondary battery comprised of the composition of claim 1 .
32 . The secondary battery of claim 31 , wherein the secondary battery is comprised of an anode comprising a lithium metal.
33 . (canceled)
34 . (canceled)