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Abstract

Disclosed is a positive electrode that has a low equivalent weight and high cell voltage and consequently a high specific energy, and a high discharge rate pulse capability. Also disclosed are methods for fabricating active-sulfur-based composite electrodes, and battery cells incorporating such electrodes. The batteries of this invention are preferably rechargeable and operate at high sulfur utilization over many cycles. Positive electrodes according to the present invention are composed of at least two electrochemically active materials: an 'active-sulfur' material, and a second electrochemically active material having a higher discharge rate than the active-sulfur component. The active-sulfur component is also oxidizing with respect to the higher discharge rate material. In operation, the active-sulfur component of the positive electrode discharges to satisfy power demands below its maximum discharge rate. The high discharge rate (but relatively low capacity) material is discharged to satisfy power demands that exceed the active-sulfur's discharge rate. The high discharge rate material in the positive electrode may be effectively recharged (or 'regenerated') chemically by oxidation by the active-sulfur material during a 'resting' phase, that is, when the power demands on a battery cell in which the cathode is incorporated are low enough that they may be met without exceeding the maximum discharge rate of the active-sulfur component of the positive electrode.

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First Claim