University of California

Duke University

Xintek, Inc.

Chunsheng Du

Otto Z Zhou

Jie Liu

Bo Gao

Qi Qiu

Ning Pan

Cheng Qian

Carbon nanotube material having an outer diameter less than 10 nm and a number of walls less than ten are disclosed. Also disclosed are an electron field emission device including a substrate, an optionally layer of adhesion-promoting layer, and a layer of electron field emission material. The electron field emission material includes a carbon nanotube having a number of concentric graphene shells per tube of from two to ten, an outer diameter from 2 to 8 nm, and a nanotube length greater than 0.1 microns. One method to fabricate carbon nanotubes includes the steps of (a) producing a catalyst containing Fe and Mo supported on MgO powder, (b) using a mixture of hydrogen and carbon containing gas as precursors, and (c) heating the catalyst to a temperature above 950&#xb0; C. to produce a carbon nanotube. Another method of fabricating an electron field emission cathode includes the steps of (a) synthesizing electron field emission materials containing carbon nanotubes with a number of concentric graphene shells per tube from two to ten, an outer diameter of from 2 to 8 nm, and a length greater than 0.1 microns, (b) dispersing the electron field emission material in a suitable solvent, (c) depositing the electron field emission materials onto a substrate, and (d) annealing the substrate.

Method of synthesizing small-diameter carbon nanotubes with electron field emission properties

One embodiment of the present invention provides a process for fabricating an electrode for a capacitor using carbon nanotubes (CNTs), wherein the electrode comprises a metal substrate and a layer of active material (CNTs) coated onto the metal substrate. Specifically, the process starts by dispersing CNTs in a solvent to form a suspension. Next, the CNTs are charged in the suspension. The metal substrate is then immersed in the suspension. Next, the CNTs are deposited onto the metal substrate using electrophoretic deposition (EPD) to form the layer of active material on the metal substrate. In particular, the layer of active material is formed on the metal substrate without using a binder, which effectively reduces contact resistance between the active material and the metal substrate.

High power density supercapacitors with carbon nanotube electrodes

Growing community of inventors

Davis, CA, United States of America

Chunsheng Du