Method for synthesis of solvent-free lithium boron cluster based salts
AssigneeToyota Motor Engineering & Manufacturing North America, Inc.
InventorsOscar Tutusaus, Rana Mohtadi
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Abstract
An effectively solvent-free alkali metal or alkali earth metal closo-borate salt is prepared in the presence of a non-aqueous solvent where the solvent can be removed to levels below one mole percent of the salt. The process involves the exchange of cations with a closo-borate anion via an acid-base process or a metathesis process. The solvent is removed from the alkali metal or alkali earth metal closo-borate salt by heating. The temperature can be greater than the melting point of the salt but lower than temperatures where decomposition occurs.
Claims20
A process for preparing a solvent-free alkali metal or alkali earth metal closo-borate salt, the process comprising:
- providing a first salt consisting of a first salt cation and a closo-borate;
- providing a second salt consisting of an alkali metal or an alkali earth metal and a second salt anion;
- providing at least one solvent;
- combining the first salt, the second salt, and the at least one solvent to form an alkali metal or alkali earth metal closo-borate;
- isolating the alkali metal or alkali earth metal closo-borate;
- and
- removing the at least one solvent by heating and/or vacuum the alkali metal or alkali earth metal closo-borate salt wherein the at least one solvent is present in an amount less than one mole percent of a solvent-free alkali metal or alkali earth metal closo-borate, wherein the alkali metal or alkali earth metal closo-borate has a structure:
- M(CmBiH(m+i)−jZjZn
- wherein:
- M is Li, Na, K, Cs, Rb, Be, Mg, Ca, or Sr;
- n is 1 or 2;
- m is 0, 1, or 2;
- m+i is 6 to 12;
- j is 0 to m+i−1;
- and Z is F, Cl, Br, I, alkyl, alkoxy, arylalkyl, aryl, aryloxy, or alkylaryl, wherein any non-halogen Z is partially or completely fluorinated.
An electrochemical device, the electrochemical device comprising:
- a solid-state electrolyte comprising an alkali metal or alkali earth metal closo-borate of the structure:
- M(CmBiH(m+i)−jZj)n
- wherein:
- M is Li, Na, K, Cs, Rb, Be, Mg, Ca, or Sr;
- n is 1 or 2;
- m is 0, 1, or 2;
- m+i is 6 to 12;
- j is 0 to m+i−1;
- and Z is F, Cl, Br, I, alkyl, alkoxy, arylalkyl, aryl, aryloxy, or alkylaryl, wherein any non-halogen Z can be partially or completely fluorinated;
- an anode comprising an alkali metal or alkali earth metal of equal atomic number as a cation of the alkali metal or alkali earth metal closo-borate;
- and
- a cathode, wherein the solid-state electrolyte is free of water and has less than one mole percent of an organic solvent relative to the alkali metal or alkali earth metal closo-borate.
Dependencies are inferred from the claim text.