Coated carbon nanotube array electrodes

An electrical energy storage device comprising:

• an electrically conducting carbon nanotube electrode comprising a plurality of carbon nanotubes in a three-dimensional array;
• and
• an electrically conducting material that is present as a uniform surface coating on the surface of individual nanotubes,
• wherein a majority of said nanotubes are randomly aligned within a series of mutually parallel planes in a manner so as to be packed densely enough to produce multiple points of contact thereamong, whereby electrical continuity is established throughout said three-dimensional array.

A method of preparing an electrically conductive aligned carbon nanotube array comprising the steps of:

• contacting a carbon nanotube substrate comprising a plurality of substantially linear mutually aligned carbon nanotubes with a monomeric compound capable of forming an electrically conducting polymeric material that is dissolved in an aqueous or organic solvent containing an electrolyte material such that said carbon nanotube substrate functions as a first electrode in an electrochemical cell;
• introducing a second electrode material to form a second electrode in the electrochemical cell;
• and
• applying an electrical potential between the first electrode and the second electrode to cause an electrochemical polymerization of the monomeric compound to the corresponding electrically conducting polymer whereby said electrically conducting polymer provides an adherent surface coating on the individual carbon nanotubes.