Air-Controlled Electrosprayed 3D Graphene/CNT/Noble Metal Nanoparticle Electrodes for Energy Storage Applications

Evan K. Lee, Sophie R. Cohen, Melanie L. George, Vesa Ibrahimi, Michael J. Williams,

Caspar C. Yi, Enoch A. Nagelli

Department of Chemistry & Life Science, United States Military Academy, West Point, New York 10996

Abstract

The enhanced electrical, thermal, chemical, and mechanical stability of graphene and carbon nanotubes (CNTs) offer an ideal platform for electrode design for energy storage applications.

Here we utilize spontaneous galvanic displacement driven by reduction potential difference to produce three-dimensional (3D) graphene-CNT-noble metal nanoparticle thin films without the use of any chemical reducing agents. A graphene-CNT slurry with a poly(acrylic acid) (PAA) binder is air-controlled electrosprayed onto copper foil to create thin film electrodes. The resulting copper supported graphene-CNT electrodes are immersed into aqueous noble metal salt solutions (HAuCl₄, K₂PtCl₄, and Na₂PdCl₄) to enable electroless noble metal nanoparticle deposition onto the 3D graphene-CNT network through a galvanic displacement reaction with copper. Scanning electron microscopy (SEM) imaging confirms that the carbon nanomaterials are integrated with noble metal nanoparticles forming an overall 3D electrode structure. Raman spectroscopy verifies the characteristic D-band, G-band, and 2D-band peaks from the graphitic structure within the 3D carbon and noble metal nanostructure. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) are used to characterize the electrochemical properties of the electrodes. We demonstrate that the use of an energy-free and spontaneous process based on the difference in thermodynamic reduction potentials as the driving force for producing carbon nanomaterial/noble metal nanostructured electrodes for batteries and fuel cells. This process is a more simple, scalable, and cost-efficient alternative to current methods for developing lightweight and catalytic electrodes for energy storage applications, such as lithium-ion batteries, lithium-air batteries, and fuel cells.

KEYWORDS: Graphene, Carbon Nanotubes, Noble Metal Nanoparticles, Batteries, Fuel Cells, Thin Film Electrodes, Energy Storage and Conversion

CONTACT: Dr. Enoch Nagelli, Department of Chemistry and Life Science, United States Military Academy, West Point, New York 10996. Email: enoch.nagelli@westpoint.edu