Material and device properties modification by electrochemical charge injection in the absence of contacting electrolyte for either local spatial or final states
View Patent ↗In some embodiments, the present invention is directed to processes for the combination of injecting charge in a material electrochemically via non-faradaic (double-layer) charging, and retaining this charge and associated desirable properties changes when the electrolyte is removed. The present invention is also directed to compositions and applications using material property changes that are induced electrochemically by double-layer charging and retained during subsequent electrolyte removal. In some embodiments, the present invention provides reversible processes for electrochemically injecting charge into material that is not in direct contact with an electrolyte. Additionally, in some embodiments, the present invention is directed to devices and other material applications that use properties changes resulting from reversible electrochemical charge injection in the absence of an electrolyte.
1. A device having tunable response that comprises:
(a) a nanostructured electrode component C of a first electrochemical electrode and an electrode component D of a second electrochemical electrode;
(b) an ionic ally conducting material that is substantially electronically nonconducting that connects said first and said second electrochemical electrodes; and
(c) a means of providing a voltage between said first and said second electrochemical electrodes, wherein
(i) the electrode component C is not in direct contact with an electrolyte,
(ii) the electrode component C has an achievable capacitance of above about 0.1 F/g for substantially non-faradaic charging,
(iii) the major volume fraction of C does not function predominately as a catalyst,
(iv) properties changes of the electrode component C in response to predominately non-faradaically injected charge are used to achieve device performance, and (v) the device is operable for use as an electron emission device, and wherein,
(A) the device response is at least partially effected by a change in the degree of non-faradaic charge injection in the electrode component C, and
(B) the nanostructured electrode component C comprises a nanofiber.
2. The device of claim 1 , wherein electrochemical charge injection into said nanofiber causes a variation in field emission.
3. The device of claim 2 , wherein said nanofiber is a nanotube that is opened in a region selected from the group consisting of an end region, a side wall region, and combinations thereof.
4. The device of claim 3 , wherein the nanotube is electronically contacted with an electronically conducting material that is intercalated with ions, and wherein the open region is located in a material comprising mobile ions that are sufficiently small in size so as be capable of fitting inside said nanotube.
5. The device of claim 3 , wherein the nanotube changes field emission properties as a result of electrochemically inserting ions inside the volume of said nanotube.
6. The device of claim 5 , wherein the ions electrochemically inserted in the nanotube are at least 10 times more numerous than those electrochemically deposited on the exterior surface of said nanotube.
7. A device having tunable response that comprises:
(a) a nanostructured electrode component C of a first electrochemical electrode and an electrode component D of a second electrochemical electrode;
(b) an ionic ally conducting material that is substantially electronically nonconducting that connects said first and said second electrochemical electrodes; and
(c) a means of providing a voltage between said first and said second electrochemical electrodes, wherein
(i) the electrode component C is not in direct contact with an electrolyte,
(ii) the electrode component C has an achievable capacitance of above about 0.1 F/g for substantially non-faradaic charging,
(iii) the major volume fraction of C does not function predominately as a catalyst,
(iv) properties changes of the electrode component C in response to predominately non-faradaically injected charge are used to achieve device performance, and
(v) the device is operable for use as an electron emission device, and wherein,
(A) the device response is at least partially effected by a change in the degree of non-faradaic charge injection in the electrode component C, and
(B) the device is operable for use as a cold cathode in devices selected from the group consisting of a flat panel display, a lighting fixture, an electron microscope, a discharge tube for over-voltage protection, and combinations thereof.