Aprotic electrolyte capacitors and methods of making the same
First Claim
1. An electrolyte comprising a solution of (a) at least one salt selected from the group consisting of alkali metal salts, transition metal salts, ammonium and ammonium derivative salts, zinc salts, cadmium salts, mercury salts, lead salts, bismuth salts and thallium salts of (b) at least one acid selected from the group consisting of monobasic, dibasic and tribasic acids (c) in an aprotic solvent substantially free of protic impurities,said aprotic solvent having polar groups which impart high solvation power to said solvent andwherein said polar groups are free of labile hydrogen atoms.
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Abstract
An electrolyte for use in a capacitor or a battery comprising a solution of (a) at least one salt selected from the group consisting of alkali metal salts, transiton metal salts, ammonium and ammonium derivatives salts, zinc salts, cadmium salts, mercury salts, lead salts, bismuth salts and thallium salts of (b) at least one acid selected from the group consisting of monobasic, dibasic and tribasic acids (c) in an aprotic solvent substantially free of protic impurities. The acid may be selected from the group consisting of perchloric acid, tetraflouboric acid, thiocyanic acid, trifluoromethanesulphonic acid and haloid acids. The salts may be selected from the group consisting of partial esters of at least one of boric, sulphuric and phosphoric acid reacted with compounds containing an alcohol group or may be an alkali metal tetrafluroborate. The capacitor is stable and has improved linearity, working voltage, capacitance per unit area, shelf life size, leakage current, and internal series resistance. The electrolyte is formed by purifying the aprotic solvent so that it is free of protic impurities and dissolving one or more salts therein. If the salt contains water of hydration, the solution is dried. Electrolytic capacitors, double layer capacitors or batteries are formed.
92 Citations
17 Claims
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1. An electrolyte comprising a solution of (a) at least one salt selected from the group consisting of alkali metal salts, transition metal salts, ammonium and ammonium derivative salts, zinc salts, cadmium salts, mercury salts, lead salts, bismuth salts and thallium salts of (b) at least one acid selected from the group consisting of monobasic, dibasic and tribasic acids (c) in an aprotic solvent substantially free of protic impurities,
said aprotic solvent having polar groups which impart high solvation power to said solvent and wherein said polar groups are free of labile hydrogen atoms.
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2. An electrolyte comprising a solution of (a) at least one salt selected from the group consisting of alkali metal salts, transition metal salts, ammonium and ammonium derivative salts, zinc salts, cadmium salts, mercury salts, lead salts, bismuth salts and thallium salts of (b) at least one acid selected from the group consisting of monobasic, dibasic and tribasic acids (c) in an aprotic solvent substantially free of protic impurities,
wherein said acid is selected from the group consisting of perchloric acid, tetraflouboric acid, thiocyanic acid, trifluoromethanesulphonic acid and haloid acids.
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3. An electrolyte comprising a solution of (a) at least one salt selected from the group consisting of alkali metal salts, transition metal salts, ammonium and ammonium derivative salts, zinc salts, cadmium salts, mercury salts, lead salts, bismuth salts and thallium salts of (b) at least one acid selected from the group consisting of monobasic, dibasic and tribasic acids (c) in an aprotic solvent substantially free of protic impurities,
wherein said salts are selected from the group consisting of partial esters of at least one of boric, sulphuric and phosphoric acid reacted with compounds containing an alcohol group.
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4. An electrolyte comprising a solution of an alkali metal tetrafluroborate in an aprotic solvent substantially free of protic impurities.
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5. An electrolyte comprising a solution of a sodium salt of di(methoxytriethyleneglycol) borate in an aprotic solvent substantially free of protic impurities.
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6. An electrolyte comprising a solution of (a) at least one salt selected from the group consisting of alkali metal salts, transition metal salts, ammonium and ammonium derivative salts, zinc salts, cadmium salts, mercury salts, lead salts, bismuth salts and thallium salts of (b) at least one acid selected from the group consisting of monobasic, dibasic and tribasic acids (c) in an aprotic solvent substantially free of protic impurities,
wherein said solvent comprises at least one of the group consisting of alkyl carbonates, alkylene carbonates, alkylene glycol derivatives, dialkylene glycol derivatives, trialkylene glycol derivatives, poly(alkylene glycol) derivatives, sulphoxides, substituted amides, substituted amines, cyclic ethers, lactams, lactones, anhydrides, esters, urethanes, ureidos, nitriles, lactate esters, nitrile esters, diketones and siloxanes, wherein in any of said compounds the oxygen atoms are replaced with sulphur atoms.
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7. A method for forming an electrolyte comprising the steps of:
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purifying an aprotic solvent so that it is substantially free of protic impurities, dissolving a salt in the solvent to form a solution, impregnating the solution into an etched aluminum anode foil, providing a conductive cathode; assembling said cathode to said impregnated anode; providing between said anode and said cathode a low conductivity spacer with openings therein, to thereby form a capacitor. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for forming an electrolyte comprising the steps of:
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purifying an aprotic solvent so that it is substantially free of protic impurities, and dissolving a salt in the solvent to form a solution; preparing a paste of high surface area carbon particles, forming at least one electrode from said paste; and placing said at least one electrode in contact with said electrolyte to form at least part of a double layer capacitor.
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Specification