Self-ordered nanotubes of titanium oxides and titanium alloy oxides for energy storage and battery applications

Abstract

The present disclosure provides oxide nanotubes formed by anodizing and oxidatively-annealing a titanium or titanium allow substrate with or without ultrasonication. If desired, carbon nanotubes may be grown in the oxide nanotubes. The substrates show improved specific capacity and charge-discharge rates for use as an electrode in lithium-ion batteries.

1 - 20 . (canceled) 
     
     
         21 . A method of manufacturing an anodized and oxidatively-annealed titanium oxide or for energy storage, comprising: anodizing a titanium substrate under conditions sufficient to form an anodized titanium oxide having a plurality of self-ordered oxide nanotubes on the anodized surface; and annealing the oxide nanotubes in a controlled oxidizing atmosphere to produce an anodized and oxidatively-annealed titanium oxide substrate having a surface area sufficient to incorporate ions for energy storage. 
     
     
         22 . The method of  claim 21 , wherein the anodizing step comprises electrochemically anodizing the titanium material in an aqueous or non-aqueous electrolyte solution containing a fluoride salt. 
     
     
         23 . The method of  claim 22 , wherein the non-aqueous solution is a polyhydric alcohol selected from the group consisting of glycerol, ethylene glycol, diethylene glycol, and mixtures thereof. 
     
     
         24 . The method of  claim 22 , wherein the electrolyte solution further comprises a complexing agent. 
     
     
         25 . The method of  claim 21 , wherein the anodizing step further comprises ultrasonicating the electrolyte solution during anodization. 
     
     
         26 . The method of  claim 21 , further comprising the steps of:
 electrodepositing a plurality of catalyst particles in the oxide nanotubes to provide nucleation sites for carbon nanotube growth, and growing carbon nanotubes at the nucleation sites by introducing a carbon source, hydrogen gas, and an inert gas onto the titanium oxide or titanium alloy oxide substrate under chemical vapor deposition process conditions.   
     
     
         27 . A method of manufacturing an anodized titanium alloy oxide substrate, comprising: anodizing a titanium alloy substrate under conditions sufficient to form anodized titanium alloy oxide having a plurality of self-ordered oxide nanotubes on the anodized surface; and annealing the oxide nanotubes in a controlled gaseous atmosphere to produce an anodized titanium alloy oxide substrate. 
     
     
         28 . The method of  claim 27 , wherein the anodizing step comprises electrochemically anodizing the titanium alloy material in an aqueous or non-aqueous electrolyte solution containing a fluoride salt. 
     
     
         29 . The method of  claim 28 , wherein the non-aqueous solution is a polyhydric alcohol is selected from the group consisting of glycerol, ethylene glycol, diethylene glycol, and mixtures thereof. 
     
     
         30 . The method of  claim 27 , wherein the electrolyte solution further comprises a complexing agent. 
     
     
         31 . The method of  claim 27 , wherein the anodizing step further comprises ultrasonicating the electrolyte solution during anodization.