Use of hydroquinone to precondition manganese dioxide for use in rechargeable electrochemical cells

摘要

A method of preconditioning manganese dioxide for use in a rechargeable alkaline electrochemical cell. The method includes the step of contacting unreduced manganese dioxide (e.g., electrolytic manganese dioxide) with a solution of hydroquinone in an environment having a pH greater than or equal to 5 that is essentially free of dissolved oxygen to partially reduce the unreduced manganese dioxide to manganese dioxide generally represented by the formula MnOx wherein x is between about 1.80 and about 1.92. Partially reducing the manganese dioxide to an oxidation state in this range before the cell is finally assembled and sealed lessens the degree by which the capacity of the cell is decreased as the cell is cycled and improves the overall performance of the cell. Also provided are preconditioned manganese dioxide suitable for use in a rechargeable alkaline electrochemical cell, a method of forming a rechargeable alkaline electrochemical cell containing a cathode having manganese dioxide as its active ingredient, and a rechargeable alkaline electrochemical cell.