HIGH VOLTAGE RECHARGEABLE MAGNESIUM CELLS HAVING A NON-AQUEOUS ELECTROLYTE
A electrochemical cell having an non-aqueous electrolyte is provided. The properties of the electrolyte include high conductivity, high Coulombic efficiency, and an electrochemical window that can exceed 3.5 V vs. Mg/Mg +2 . The use of the electrolyte promotes the electrochemical deposition and dissolution of Mg without the use of any Grignard reagents, other organometallic materials, tetraphenyl borate, or tetrachloroaluminate derived anions. Other Mg-containing electrolyte systems that are expected to be suitable for use in secondary batteries are also described.
1 . A method of preparing a non-aqueous electrolyte solution for use in an electrochemical cell, comprising the step of reacting a magnesium halide and a magnesium salt of formula MgZ 2 , where Z is a polyatomic monovalent anion, in a solvent.
2 . The method of claim 1 , wherein Z is a polyatomic monovalent anion selected from the group of polyatomic monovalent anions described in Table I, or mixtures thereof.
3 . The method of claim 1 , wherein said magnesium halide is magnesium chloride, said magnesium salt is Mg[N(CF 3 SO 2 ) 2 ] 2 , and said solvent is THF, DME, ethyl diglyme, butyl diglyme, or a mixture thereof.
4 . The method of claim 1 , wherein a magnesium halide:MgZ 2 ratio is in the range from 4:1 to 1:4.
5 . The non-aqueous electrolyte solution of claim 1 , wherein a magnesium halide:MgZ 2 ratio is in any proportion between 4:1 and 1:1.
6 . The method of claim 1 , further comprising the step of conditioning said non-aqueous electrolyte solution by electrochemical polarization.
7 . An electrochemical cell, comprising:
a non-aqueous electrolyte solution comprising:
at least one organic solvent; and
at least one electrolytically active, soluble, inorganic Magnesium (Mg) salt complex represented by the formula Mg n+1 X (2*n) Z 2 in which n is in the range from one-quarter to four, X is a halide, and Z is an inorganic polyatomic monovalent anion;
a magnesium anode and
a cathode capable of magnesium intercalation, conversion, or displacement reaction.
8 . The electrochemical cell of claim 7 , wherein said magnesium anode is selected from the group consisting of Mg metal, Anatase TiO 2 , rutile TiO 2 , Mo 6 S 8 , FeS 2 , TiS 2 , and MoS 2 .
9 . The electrochemical cell of claim 7 , wherein said Mg alloy is selected from the group of Mg alloys consisting of AZ31, AZ61, AZ63, AZ80, AZ81, AZ91, AM50, AM60, Elektron 675, ZK51, ZK60, ZK61, ZC63, M1A, ZC71, Elektron 21, Elektron 675, Elektron, and Magnox.
10 . The electrochemical cell of claim 7 , wherein said magnesium intercalation cathode is selected from the group consisting of Chevrel phase Mo 6 S 8 , MnO 2 , CuS, Cu 2 S, Ag 2 S, CrS 2 , VOPO 4 , a layered structure compound, a spinel structured compound, a zinc blende structure, a rock salt structured compound, a NASICON structured compound, a Cadmium iodide structured compound, an Olivine structured compound, a Tavorite structured compound, a pyrophosphate, a monoclinic structured compound, and a fluoride.
11 . The electrochemical cell of claim 10 , wherein said layered structure compound is selected from the group consisting of TiS 2 , V 2 O 5 , MgVO 3 , MoS 2 , MgV 2 O 5 , and MoO 3 .
12 . The electrochemical cell of claim 10 , wherein said spinel structured compound is selected from the group consisting of CuCr 2 S 4 , MgCr 2 S 4 , MgMn 2 O 4 , MgNiMnO 4 , and Mg 2 MnO 4 .
13 . The electrochemical cell of claim 10 , wherein said NASICON structured compound is selected from the group consisting of MgFe 2 (PO 4 ) 3 and MgV 2 (PO 4 ) 3 .
14 . The electrochemical cell of claim 10 , wherein said Olivine structured compound is selected from the group consisting of MgMnSiO 4 and MgFe 2 (PO 4 ) 2 .
15 . The electrochemical cell of claim 10 , wherein said Tavorite structured compound is Mg 0.5 VPO 4 F.
16 . The electrochemical cell of claim 10 , wherein said pyrophosphate is selected from the group consisting of TiP 2 O 7 and VP 2 O 7 .
17 . The electrochemical cell of claim 10 , wherein said fluoride is selected from the group consisting of MgMnF 4 and FeF 3 .