Organic phosphate additives for nonaqueous electrolyte in alkali metal electrochemical cells

In combination with an implantable medical device requiring at least one current pulse for a medical device operating function, an electrochemical cell which is dischargeable to deliver the current pulse while exhibiting reduced voltage delay, the cell which comprises:

• a) an anode comprising an alkali metal;
• b) a solid cathode of electrically conductive material;
• and
• c) a nonaqueous electrolyte activating the anode and the cathode, the nonaqueous electrolyte comprising:
• i) a phosphate additive having the general formula (R.sup.1 O)P(.dbd.O)(OR.sup.2)(OR.sup.3), wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different and they can be a hydrogen atom or an organic group, with at least one of them being an unsaturated organic ground containing 2 to 13 carbon atoms and having the formula CR.sup.4 R.sup.5 R.sup.6 with at least R.sup.4 being an aromatic substituent or an unsaturated organic or inorganic group and wherein if any of the remaining groups of R.sup.1, R.sup.2 and R.sup.3 is a saturated organic group, the saturated organic group contains 1 to 13 carbon atoms;
• and
• ii) an alkali metal salt dissolved therein, wherein the alkali metal of the salt is the same as the alkali metal comprising the anode, and wherein the activated anode and cathode provide the electrochemical cell dischargeable to deliver at least one current pulse for the medical device operating function, wherein the current pulse is of an electrical current of a greater amplitude than that of a prepulse current immediately prior to the pulse such that the pulse one end potential minus the pulse one minimum potential is less than about 0.2 volts.

An electrochemical cell which is dischargeable to deliver a current pulse while exhibiting reduced voltage delay, which comprises:

• a) an anode comprising an alkali metal;
• b) a solid cathode of electrically conductive material;
• and
• c) a nonaqueous electrolyte activating the anode and the cathode, the nonaqueous electrolyte comprising:
• i) a first solvent selected from the group consisting of an ester, an ether and a dialkyl carbonate, and mixtures thereof;
• ii) a second solvent selected from the group consisting of a cyclic carbonate, a cyclic ester and a cyclic amide, and mixtures thereof;
• iii) a dibenzyl phosphate additive present in the electrolyte at a concentration up to about 0.20M;
• and
• iv) an alkali metal salt dissolved therein, wherein the alkali metal of the salt is the same as the alkali metal comprising the anode, and wherein the activated anode and cathode provide the electrochemical cell dischargeable to deliver at least one current pulse of electrical current of a greater amplitude than that of a prepulse current immediately prior to the pulse such that the pulse one end potential minus the pulse one minimum potential is less than about 0.2 volts.

An electrochemical cell, which comprises:

• a) an anode comprising an alkali metal;
• b) a solid cathode of electrically conductive material;
• and
• c) a nonaqueous electrolyte activating the anode and the cathode, the nonaqueous electrolyte comprising a phosphate additive having the general formula (R.sup.1 O)P(.dbd.O)(OR.sup.2)(OR.sup.3), wherein at least one of the R groups contains an sp.sup.2 hybridized carbon atom bonded to an sp.sup.3 hybridized carbon atom bonded to the oxygen atom bonded to the phosphorous atom.

In combination with an implantable medical device requiring at least one current pulse for a medical device operating function, an electrochemical cell which is dischargeable to deliver the current pulse while exhibiting reduced voltage delay, the cell which comprises:

• a) an anode comprising an alkali metal;
• b) a solid cathode of electrically conductive material;
• and
• c) a nonaqueous electrolyte activating the anode and the cathode, the nonaqueous electrolyte comprising:
• i) a phosphate additive having the general formula (R.sup.1 O)P(.dbd.O)(OR.sup.2)(OR.sup.3), wherein at least one of the R groups contains an sp.sup.2 hybridized carbon atom bonded to an sp.sup.3 hybridized carbon atom bonded to the oxygen atom bonded to the phosphorous atom;
• and
• ii) an alkali metal salt dissolved therein, wherein the alkali metal of the salt is the same as the alkali metal comprising the anode, and wherein the activated anode and cathode provide the electrochemical cell dischargeable to deliver at least one current pulse for the medical device operating function, wherein the current pulse is of an electrical current of a greater amplitude than that of a prepulse current immediately prior to the pulse such that the pulse one end potential minus the pulse one minimum potential is less than about 0.2 volts.