Method of making silver vanadium oxyfluorides for nonaqueous lithium electrochemical cells
View Patent ↗An electrochemical cell comprising a lithium anode and a fluorinated silver vanadium oxide cathode activated with a nonaqueous electrolyte is described. The fluorinated silver vanadium oxide is of the formula Ag 4 V 2 O 11-x F x , wherein x ranges from about 0.02 to about 0.3.
1. A method for providing a cathode active material, comprising the steps of:
a) providing a silver-containing ingredient selected from the group consisting of Ag, Ag 2 O, Ag 2 CO 3 , AgNO 3 , AgNO 2 , Ag 2 O 2 , AgVO 3 , and Ag (CH 3 CO 2 );
b) providing a vanadium-containing compound selected from the group consisting of V 2 O 5 , NH 4 VO 3 , AgVO 3 , VO, VO 1.27 , VO 2 , V 2 O 4 , V 2 O 3 , V 3 O 5 , V 4 O 9 , and V 6 O 13 ;
c) providing a fluorine-containing compound selected from the group consisting of AgF, VOF 3 , and mixtures thereof;
d) mixing the silver-containing ingredient, the vanadium-containing compound and the fluorine-containing compound together;
e) heating the mixture to obtain fluorinated silver vanadium oxide as a cathode active material;
f) providing a solution of an organic solvent having the fluorinated silver vanadium oxide mixed therein thereby forming an admixture paste;
g) subjecting the paste to at least one pressing step thereby forming a cathode sheet;
h) removing any residual solvent material from the cathode sheet;
i) subjecting the cathode sheet to a forming means that serves to provide at least one cathode plate having a desired geometric shapes; and
j) laminating at least one of the thusly formed cathode plates on at least one side of a current collector.
2. The method of claim 1 wherein step (f) further comprises the addition of binder and conductor materials.
3. The method of claim 1 wherein step (f) further comprises selecting the solvent material from the group consisting of water and an inert organic material.
4. The method of claim 1 wherein step (d) further comprises mixing the silver-containing material and the vanadium-containing material in a mole ratio of about 1:2.
5. The method of claim 1 wherein step (d) further comprises providing the silver: vanadium: fluorine at a molar ration of 2:4:0.4.
6. The method of claim 1 wherein step (e) further comprises heating the mixture of the silver-containing material, the vanadium-containing material and the fluorine-containing material to a temperature of from about 250° C. to about 400° C.
7. The method of claim 5 wherein step (e) further comprises heating the mixture of the silver-containing material, the vanadium-containing material and the fluorine-containing material for about 0.5 hour to about 24 hours.