Synthesis of intercalatable layered stable transition metal chalcogenides and alkali metal-transition metal chalcogenides
AssigneeCombustion Engineering, Inc.
InventorDavid N. Palmer
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Abstract
Intercalatable layered or lamellar stable transition metal chalcogenides, such as CrS.sub.2, usable as cathode active materials and intercalatable layered or lamellar stable alkali metal-transition metal chalcogenides, such as LiCrS.sub.2, usable as cathode active materials as well as anode active materials are synthesized by ion implantation and annealing techniques.
Claims9
A process for treating the surface of a transition metal substrate to form into the surface an intercalatable layered stable transition metal chalcogenide having the general formula MX.sub.n where M is a transition metal selected from the group consisting of Ti, V, Cr, Fe, Zr and Nb;
- X is sulfur;
- and n is 2-3;
- which comprises:
- ion implanting sulfur at an implantation energy in the range of about 150-200 kiloelectron volts and at a saturation dosage of about 10.sup.18 sulfur atoms/cm.sup.2 into the suface of the transition metal substrate to a depth of about 1300-2200.ANG.;
- and
- annealing the sulfur-implanted substrate under a vacuum of from about 1.times.10.sup.-5 torr to about 1.times.10.sup.-6 torr at a temperature of from about 100.degree. C. to about 300.degree. C. for form about 8 hours to about 48 hours.
The process for treating the surface of a transition metal substrate to form into the surface an intercalatable layered stable alkali metal-transition metal chalcogenide having the general formula A.sub.m MX.sub.n where A is an alkali metal selected from the group consisting of lithium, sodium and potassium;
- M is a transition metal selected from the group consisting of Ti, V, Cr, Fe, Zr and Nb;
- X is sulfur;
- m is 1-4;
- and n is 2-3;
- which comprises:
- ion implanting sulfur at an implantation energy in the range of about 150-200 kiloelectron volts and at a saturation dosage of about 10.sup.18 sulfur atoms/cm.sup.2 into the surface of the transition metal substrate to a depth of about 1300-2200.ANG.;
- annealing the sulfur-implanted substrate under a vacuum of from about 1.times.10.sup.-5 torr to about 1.times.10.sup.-6 torr at a temperature of from about 100.degree. C. to about 300.degree. C. for from about 8 hours to about 48 hours;
- ion implanting the alkali metal at an implantation energy in the range of about 150-200 kiloelectron volts and at a saturation dosage of about 10.sup.18 alkali metal atoms/cm.sup.2 into the surface of the annealed sulfur-implanted substrate to a depth of about 1300-2200 .ANG.;
- and
- annealing the alkali metal-implanted substrate under a vacuum of from about 1.times.10.sup.-5 torr to about 1.times.10.sup.-6 torr at a temperature of from about 80.degree. C. to about 150.degree. C. for from about 8 hours to about 48 hours.
Dependencies are inferred from the claim text.