Vertically aligned carbon nanotube arrays as electrodes

Abstract

Embodiments of the present disclosure pertain to electrodes that include a plurality of vertically aligned carbon nanotubes and a metal associated with the vertically aligned carbon nanotubes. The vertically aligned carbon nanotubes may be in the form of a graphene-carbon nanotube hybrid material that includes a graphene film covalently linked to the vertically aligned carbon nanotubes. The metal may become reversibly associated with the carbon nanotubes in situ during electrode operation and lack any dendrites or mossy aggregates. The metal may be in the form of a non-dendritic or non-mossy coating on surfaces of the vertically aligned carbon nanotubes. The metal may also be infiltrated within bundles of the vertically aligned carbon nanotubes. Additional embodiments pertain to energy storage devices that contain the electrodes of the present disclosure. Further embodiments pertain to methods of forming said electrodes by applying a metal to a plurality of vertically aligned carbon nanotubes.

What is claimed is: 
     
         1 - 5 . (canceled) 
     
     
         6 . A method comprising:
 wetting carbon nanotubes with an electrolyte, the electrolyte having a concentration of ions of a metal, to form electrolyte-wetted carbon nanotubes;   providing a counter electrode of the metal in contact with the electrolyte; and   applying a voltage between the electrolyte-wetted carbon nanotubes and the counter electrode, the voltage inducing a current between the electrolyte-wetted carbon nanotubes and the counter electrode;   wherein the current between the electrolyte-wetted carbon nanotubes and the counter electrode electrochemically strips the metal from the counter electrode and plates the metal stripped from the counter electrode onto the electrolyte-wetted carbon nanotubes to form a coating of the metal over and between the carbon nanotubes.   
     
     
         7 . The method of  claim 6 , wherein the metal consists essentially of lithium. 
     
     
         8 . The method of  claim 6 , further comprising applying the current between the carbon nanotubes and the counter electrode at a current density of from one to ten milliamps per centimeter squared. 
     
     
         9 . The method of  claim 6 , further comprising holding the current constant while inducing the current between the carbon nanotubes and the counter electrode. 
     
     
         10 . The method of  claim 6 , further comprising separating the counter electrode from the carbon nanotubes using a membrane and the electrolyte. 
     
     
         11 . The method of  claim 10 , further comprising replacing the counter electrode with a cathode. 
     
     
         12 . The method of  claim 11 , wherein the cathode comprises sulfur. 
     
     
         13 . The method of  claim 11 , further comprising assembling the cathode and the carbon nanotubes coated with the metal into an electrochemical cell. 
     
     
         14 . The method of  claim 13 , wherein the electrochemical cell includes the membrane. 
     
     
         15 . The method of  claim 13 , wherein the electrochemical cell includes the electrolyte. 
     
     
         16 . The method of  claim 6 , wherein the concentration of the ions of the metal is 4M lithium. 
     
     
         17 . The method of  claim 6 , wherein the carbon nanotubes are aligned. 
     
     
         18 . The method of  claim 6 , further comprising growing the carbon nanotubes from a substrate. 
     
     
         19 . A method comprising:
 wetting carbon nanotubes with an electrolyte, the electrolyte having a concentration of ions of a metal, to form electrolyte-wetted carbon nanotubes; and   plating the metal from the electrolyte onto the electrolyte-wetted carbon nanotubes to form a coating of the metal over and between the carbon nanotubes.   
     
     
         20 . The method of  claim 19 , further providing a counter electrode in contact with the electrolyte. 
     
     
         21 . The method of  claim 20 , wherein the counter electrode comprises the metal. 
     
     
         22 . The method of  claim 20 , wherein the counter electrode comprises a surface in contact with the electrolyte, and wherein the surface consists essentially of lithium. 
     
     
         23 . The method of  claim 20 , further comprising a separator between the carbon nanotubes and the counter electrode. 
     
     
         24 . The method of  claim 20 , further comprising inducing a current between the electrolyte-wetted carbon nanotubes and the counter electrode, the current electrochemically stripping the metal from the counter electrode and plating the metal stripped from the counter electrode onto the electrolyte-wetted carbon nanotubes to plate the metal over and between the carbon nanotubes. 
     
     
         25 . The method of  claim 24 , further comprising applying the current between the carbon nanotubes and the counter electrode at a current density of from one to ten milliamps per centimeter squared. 
     
     
         26 . The method of  claim 19 , further comprising forming a solid electrolyte interphase over the coating of the metal. 
     
     
         27 . The method of  claim 19 , wherein the coating of the metal lacks dendrites or mossy aggregates. 
     
     
         28 . The method of  claim 19 , wherein the metal consists essentially of lithium.