Substituted lithium phosphates and solid electrolytes therefrom
AssigneeE. I. Du Pont de Nemours and Company
InventorBarry Edward Taylor
Life of this patent
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Abstract
Lithium phosphates are provided which have the formula: Li.sub.1.sub.-2x.sub.-y.sub.+z Mg.sub.x M.sub.2.sub.-y.sup.4.sup.+ M.sub.y.sup.5.sup.+ (P.sub.1.sub.-z/3 Si.sub.z/3 O.sub.4).sub.3.q(Li.sub.2 O) wherein M.sup.4.sup.+ is at least one of zirconium and hafnium; M.sup.5.sup.+ is at least one of niobium and tantalum; x is 0 to about 0.15; y is 0 to about 0.5; z is 0 to about 0.3; q is 0 to about 0.2; and 2x+y-z is at least -0.1. These substituted lithium phosphates are useful as solid electrolytes in electrochemical cells such as galvanic cells and electrolytic cells.
Claims16
A lithium phosphate of the formula:
- Li.sub.1.sub.-2x.sub.-4.sub.+z Mg.sub.x M.sub.2.sub.-y.sup.4.sup.+ M.sub.y.sup.5.sup.+ (P.sub.1.sub.-2/3 Si.sub.2/3 O.sub.4).sub.3.sup.. q(Li.sub.2 O)
- wherein
- M.sup.4.sup.+ is at least one of zirconium and hafnium;
- M.sup.5.sup.+ is at least one of niobium and tantalum;
- x is 0 to about 0.15;
- y is 0 to about 0.5;
- z is 0 to about 0.3;
- q is 0 to about 0.2;
- and
- 2x+y=z is at least -0.1 and at least one of x, y and z is not equal to 0.
In an electrochemical device having:
- a. two electrodes, one of which is lithium, LiA1 or LiHg amalgam;
- b. a solid electrolyte separating the two electrodes;
- and
- c. connecting electrical conductor to complete an electrical circuit between the two electrodes;
- the improvement wherein the solid electrolyte consists essentially of a lithium phosphate of the formula:
- Li.sub.1.sub.-2x.sub.-y.sub.+z Mg.sub.x M.sub.2.sub.-y.sup.4.sup.+ M.sub.y.sup.5.sup.+ (P.sub.1.sub.-z/3 Si.sub.z/3 O.sub.4).sub.3.sup.. q(Li.sub.2 O)
- wherein
- M.sup.4.sup.+ is at least one of zirconium and hafnium;
- M.sup.5.sup.+ is at least one of niobium and tantalum;
- x is 0 to about 0.15;
- y is 0 to about 0.5;
- z is 0 to about 0.3;
- q is 0 to about 0.2;
- and
- 2x+y-z is at least -0.1.
Dependencies are inferred from the claim text.