Single-wall carbon nanotubes for hydrogen storage or superbundle formation

Abstract

A method of processing single-walled carbon nanotubes (SWNTs) in the formation of superbundles or for use in hydrogen storage, or both, is provided comprising the steps of mixing a SWNT substrate in a solvent solution into a suspension, and agitating the suspension using an ultrasonic energy means.

1 . A method of processing single-walled carbon nanotubes (SWNTs) for use in the formation of superbundles or hydrogen storage or both comprising the steps of: 
 (a) mixing a SWNT substrate in a solvent solution into a suspension; and    (b) agitating the suspension using an ultrasonic energy means.    
     
     
         2 . The process of  claim 1  wherein the solvent is a dilute acid or an oxidizing solution.  
     
     
         3 . The process of  claim 1  further comprising settling the suspension for a time sufficient to form an agglomeration of the bundles.  
     
     
         4 . The process of  claim 1  wherein the solvent is selected from a group consisting of deionized water, toluene, hexane, or alcohol.  
     
     
         5 . The process of  claim 1  wherein the solvent consists essentially of 50:50 methanol and water mixture.  
     
     
         6 . The process of  claim 1  wherein agitating comprises approximately 20 minutes at an ultrasonic power of about 90 Watts 1 cm 2 .  
     
     
         7 . The process of  claim 1  wherein agitating further comprises applying ultrasonic energy to the suspension in a flowing state.  
     
     
         8 . The process of  claim 1  wherein agitating further comprises applying ultrasonic energy to the suspension in a static state.  
     
     
         9 . The process of  claim 1  wherein the substrate is a micro crystalline graphite.  
     
     
         10 . The process of  claim 1  wherein the substrate comprises greater than 98% SWNTs by weight.  
     
     
         11 . The process of  claim 1  wherein the substrate is an impure SWNT material.  
     
     
         12 . The process of  claim 1  wherein the substrate is a multi-walled carbon nanotube material.  
     
     
         13 . The process of  claim 2  wherein the dilute acid consists essentially of HNO 3 .  
     
     
         14 . The process of  claim 2  further comprising degassing at an elevated temperature and absorbing hydrogen at an ambient temperature and pressure.  
     
     
         15 . The process of  claim 3  wherein the bundles range in size from 0.4-1 microns in diameter and 5-10 microns in length.  
     
     
         16 . The process of  claim 3  wherein the bundles comprise an essentially pure SWNTs, consisting essentially of, in percent by weight: SWNT's greater than 98%; and metal less than 0.5% wherein the SWNT's adsorb 2.0 to 7.0% hydrogen.  
     
     
         17 . The process of  claim 13  wherein the dilute acid solution is about SM HNO 3 .  
     
     
         18 . The process of  claim 14  wherein agitation comprises 16 hours at 90 W/cm 2  and the degass proceeds at a temperature of about 825 K, the hydrogen adsorption comprising approximately 6.5 wt %.  
     
     
         19 . The process of  claim 14  wherein the hydrogen is adsorbed on at least two adsorption sites, the sites capable of desorption at about 370 and 630 K.  
     
     
         20 . The process of  claim 14  wherein ambient conditions comprise room temperature and 500 torr.  
     
     
         21 . The process of  claim 14  wherein agitation comprises a time in the range of 20 minutes-24 hours using a sonication power in the range of 25-280 W/cm 2 , the final absorption capacity of the bundles having a range of 2-7 wt %.