Preparation of copper silver vanadium oxide from γ-phase SVO starting material
View Patent ↗The current invention relates to the preparation of an improved cathode active material for non-aqueous lithium electrochemical cell. In particular, the cathode active material comprises ε-phase silver vanadium oxide prepared by using a γ-phase silver vanadium oxide starting material. The reaction of γ-phase SVO with a silver salt produces the novel ε-phase SVO possessing a lower surface area than ε-phase SVO produced from vanadium oxide (V 2 O 5 ) and a similar silver salt as starting materials. Consequently, the low surface area ε-phase SVO material provides an advantage in greater long-term stability in pulse dischargeable cells.
1. A cathode for an electrochemical cell, the cathode comprising an electrode active material characterized as prepared from γ-phase silver vanadium oxide having the formula Ag 1.2 V 3 O 8.1 mixed with C u O to form a reaction mixture heated to at least one reaction temperature in an oxidizing atmosphere to produce Cu 0.2 Ag 0.8 V 2 O 5.6 having a BET surface area of about 0.31 m 2 /gram.
2. The cathode of claim 1 wherein the reaction mixture is heated to the at least one reaction temperature in a range from about 300° C. to about 550°C.
3. The cathode of claim 1 wherein the reaction mixture is heated to the at least one reaction temperature for about 5 hours to about 30 hours.
4. The cathode of claim 1 further comprising a binder and a conductive material.
5. A nonaqueous electrochemical cell, comprising:
a) an anode;
b) a cathode containing an electrode active material characterized as having been prepared from a mixture of γ-phase silver vanadium oxide having the formula Ag 1.2 V 3 O 8.1 and CuO forming a reaction mixture heated to at least one reaction temperature in an oxidizing atmosphere to produce CU 0.2 Ag 0.8 V 2 O 5.6 having a BET surface area of about 0.31 m 2 /gram; and
c) a non-aqueous electrolyte activating the anode and the cathode; and
d) a separator material electrically insulating the anode from the cathode, and of a porosity to allow for electrolyte flow.
6. The electrochemical cell of claim 5 wherein the anode is comprised of lithium.
7. The electrochemical cell of claim 5 wherein the reaction mixture is heated to the at least one reaction temperature in a range from about 300° C. to about 550°C.
8. The electrochemical cell of claim 5 wherein the reaction mixture is heated to the at least one reaction temperature for about 5 hours to about 30 hours.