Thermionic cathode with a graphene sealing layer and method of making the same
According to an embodiment of the present disclosure, a thermionic cathode includes: a cathode body having an outer surface, and a sealing layer including one or more graphene sheets on the outer surface of the cathode body. According to another embodiment of the present disclosure, a method for manufacturing a thermionic cathode includes: depositing a sealing layer including one or more graphene sheets on an outer surface of a cathode body.
1. A method for manufacturing a thermionic cathode, the method comprising:
providing a cathode body, the cathode body having an outer surface, and
depositing a sealing layer comprising 1 to 20 graphene sheets on the outer surface of the cathode body,
wherein the graphene sheets conform to the outer surface of the cathode body.
2. The method of claim 1 , wherein the depositing of the sealing layer comprises depositing the sealing layer directly onto the outer surface of the cathode body utilizing chemical-vapor-deposition.
3. The method of claim 2 , wherein the cathode body has a planar shape, a cylindrical shape, a helical shape or an irregular shape.
4. The method of claim 1 , wherein the depositing of the sealing layer comprises:
co-depositing a dopant and carbon on the outer surface of the cathode body to form a doped graphene sheet.
5. The method of claim 4 , wherein the dopant is intercalated into cells of honey comb shaped crystal lattices of the doped graphene sheet.
6. A method for manufacturing a thermionic cathode, the method comprising:
depositing a sealing layer comprising 1 to 20 graphene sheets on an outer surface of a cathode body,
wherein the depositing of the sealing layer comprises:
depositing a graphene layer on a carrier substrate to form a graphene layer-carrier laminate,
applying a polymer film on the graphene layer to form a polymer film-graphene layer-carrier laminate,
removing the carrier substrate from the polymer film-graphene layer-carrier laminate to form a polymer film-graphene layer laminate,
attaching the polymer film-graphene layer laminate on the outer surface of the cathode body, and
removing the polymer film from the polymer film-graphene layer laminate, and
wherein the thermionic cathode comprises the sealing layer and the cathode body.
7. The method of claim 6 , further comprising removing a native oxide layer from the carrier substrate prior to the depositing of the graphene layer.
8. The method of claim 6 , wherein the carrier substrate is a Cu foil or a Ni foil.
9. The method of claim 6 , wherein the depositing of the graphene layer comprises a chemical-vapor-deposition process.