A method for manufacturing a first hybrid binder-free electrode for electrochemical energy storage devices, preferably for electrochemical supercapacitors, said first hybrid binder-free electrode comprising, preferably consisting of, a conductive metal substrate and carbon nanotubes attached to the conductive metal substrate, wherein each carbon nanotube has only one single-crystal metal nanoparticle positioned at its tip with a metal nitride top layer, the method comprising the following subsequent steps: a) growing carbon nanotubes, preferably multi-walled carbon nanotubes, in a processing chamber using a tip-growth mechanism, wherein each carbon nanotube has only one single-crystal metal nanoparticle positioned at its tip, on a conductive metal substrate in a direction perpendicular to the surface of the conductive metal substrate, wherein the metal of the single-crystal metal nanoparticles and the metal of the conductive metal substrate are the same; b) providing the conductive metal substrate with the carbon nanotubes thereon, as obtained in step (a), in a processing chamber wherein the conductive metal substrate with the carbon nanotubes thereon is arranged on a conductive substrate holder that is not grounded, and evacuating said processing chamber to a pressure below 10 Pa; c) supplying nitrogen-containing gas to the evacuated processing chamber of step (b) to obtain a partial pressure of the nitrogen-containing gas of between 10 Pa and 100 Pa; d) creating a plasma inside the processing chamber using a high-frequency plasma generator; e) allowing the single-crystal metal nanoparticles at the tips of the carbon nanotubes to interact with the nitrogen-containing plasma inside the processing chamber for a time period of between 5 and 105 s, leading to the formation of a metal nitride layer on top of the single-crystal metal nanoparticles; f) turning off the high-frequency plasma generator; and g) assuring that the temperature of the processing chamber drops below a threshold value, preferably below 35 °C, and subsequently venting the processing chamber to atmospheric pressure, wherein no binder is applied during the process. a) growing carbon nanotubes, preferably multi-walled carbon nanotubes, in a processing chamber using a tip-growth mechanism, wherein each carbon nanotube has only one single-crystal metal nanoparticle positioned at its tip, on a conductive metal substrate in a direction perpendicular to the surface of the conductive metal substrate, wherein the metal of the single-crystal metal nanoparticles and the metal of the conductive metal substrate are the same; b) providing the conductive metal substrate with the carbon nanotubes thereon, as obtained in step (a), in a processing chamber wherein the conductive metal substrate with the carbon nanotubes thereon is arranged on a conductive substrate holder that is not grounded, and evacuating said processing chamber to a pressure below 10 Pa; c) supplying nitrogen-containing gas to the evacuated processing chamber of step (b) to obtain a partial pressure of the nitrogen-containing gas of between 10 Pa and 100 Pa; d) creating a plasma inside the processing chamber using a high-frequency plasma generator; e) allowing the single-crystal metal nanoparticles at the tips of the carbon nanotubes to interact with the nitrogen-containing plasma inside the processing chamber for a time period of between 5 and 105 s, leading to the formation of a metal nitride layer on top of the single-crystal metal nanoparticles; f) turning off the high-frequency plasma generator; and g) assuring that the temperature of the processing chamber drops below a threshold value, preferably below 35 °C, and subsequently venting the processing chamber to atmospheric pressure,