ELECTROLYTE SOLUTION SEQUESTERING AGENTS FOR ELECTROCHEMICALCELLS HAVING CARBONACEOUS ELECTRODES

摘要

A secondary electrochemical cell including a first electrode (4) and a counterelectrode (3) each capable of reversibly incorporating an alkali metal, an alkali metal incorporated in at least one of the electrodes and an electrolyte solution containing an organic solvent, a salt of the alkali metal and at least one sequestering agent capable of complexing with the alkali moiety of the electrolyte salt, characterized in that the first electrode includes a carbon composition having a degree of graphitization greater than about 0.40. A method for intercalating alkali metal ions into a highly graphitic carbonaceous electrode material by contacting the electrode material with an electrolyte solution of an electrolyte solvent, an alkali metal electrolyte salt and at least one sequestering agent capable of complexing with the alkali metal moiety of the electrolyte salt, which electrolyte solution is also in contact with a counterelectrode, and applying a current between the electrode material and counterelectrode so that the alkali metal ions intercalate into the electrode material from the electrolyte solution, which sequestering agent substantially prevents cointercalation of the electrolyte solvent with the alkali metal ions into the electrode material.