Chloride-free electrolyte for a magnesium battery and a method to convert a magnesium electrolyte to a chloride-free electrolyte
AssigneeToyota Motor Engineering & Manufacturing North America, Inc.
InventorsJohn G. MULDOON, Claudiu B. BUCUR
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Abstract
A method to prepare a chloride free magnesium electrolyte salt is provided. According to the method a water stable borate or carborate anion is converted to metal salt of an alkali metal or silver by an ion exchange and then converted to a chloride free magnesium salt by another ion exchange. A chloride free magnesium salt suitable as an electrolyte for a magnesium battery and a magnesium battery containing the chloride free magnesium electrolyte are also provided.
Claims29
A method to prepare a magnesium salt of formula (I):
- [A]2Mg(Solvent)y (I)
- wherein
- Solvent is a nonaqueous solvent comprising an ether oxygen and y is an integer of 2 to 6, and
- A is at least one of a water stable borate anion or carborate anion,
- the method comprising:
- at least one ion exchange operation of Mg2+ for a metal ion M+ in the nonaqueous solvent (Solvent) according to the equation (c):
- 2(A−M+)+MgBr2→A2Mg(Solvent)y+2MBr(s) (c)
- wherein M+ is at least one selected from the group consisting of Li+, Na+, K+ Rb+, Cs+ and Ag+.
A method to prepare a magnesium salt of formula (VII):
- [(C6F5)3B(C6H5)]2Mg(THF)6 (VII)
- wherein THF is a tetrahydrofuran molecule, and
- Ph is a C6H5— group,
- the method comprising:
- ion exchange of Mg for Ag in THF according to the equation:
- 2((C6H5)B(C6F5)3)Ag+MgBr2→((C6H5)B(C6F5)3)2Mg(THF)6+2AgBr
- and removal of the AgBr from the magnesium salt of formula (VII).
A method to prepare a magnesium salt of formula (VIII):
- [(Mes)3B(C6H5)]2Mg(THF)6 (VIII)
- wherein
- THF is a tetrahydrofuran molecule,
- Ph is a C6H5— group, and
- Mes is a 3,5-dimethylphenyl group,
- the method comprising:
- ion exchange of Mg for Ag in THF according to the formula:
- 2((C6H5)B(Mes)3)Ag+MgBr2→((C6H5)B(C6H5)3)2Mg(THF)6+2AgBr
- and removal of the AgBr from the magnesium salt of formula (VIII).
A magnesium electrolyte salt of formula (I):
- [A]2Mg(Solvent)y (I)
- wherein
- Solvent is a nonaqueous solvent comprising an ether oxygen and y is an integer of 2 to 6,
- A is at least one of a water stable borate anion or carborate anion, and
- the magnesium electrolyte salt is free of chlorides.
A magnesium battery, comprising:
- a negative electrode comprising magnesium;
- a positive electrode;
- a solvent;
- and
- a magnesium electrolyte of formula (I):
- [A]2Mg(Solvent)y (I)
- wherein
- Solvent of formula (I) is a nonaqueous solvent comprising an ether oxygen and y is an integer of 2 to 6,
- A is at least one of a water stable borate anion or carborate anion, and
- the magnesium electrolyte is free of chlorides.
Dependencies are inferred from the claim text.