Double chromate compositions for use as positive active material in batteries

Abstract

Novel double chromate compositions having the general formula: MBi(Cr.sub.x O.sub.y).sub.2, wherein M is silver or thallium and x is 1 and y is between about 3.7 and 4 or x is 2 and y is 7. Methods of making MBi(Cr.sub.x O.sub.y).sub.2 are characterized by reacting silver dichromate or thallium dichromate with a bismuth salt to provide equal numbers of silver or thallium atoms and bismuth atoms. Non-stoichiometric compositions wherein y is less than 4 and greater than or equal to about 3.7 are obtained by heating MBi(CrO.sub.4).sub.2 to a temperature between about 200.degree. C. and about 425.degree. C., the resulting product having an unchanged radio crystallographic structure. These double chromate compositions have particular utility in batteries as active positive material. Due to the steadiness of discharge voltage and duration of discharge of batteries employing these double chromate compositions, such batteries are especially adapted for use in clocks and in cardiostimulators or pacemakers.

Dependencies are inferred from the claim text.