Three-Dimensional Graphene Sheet-Carbon Veil Thermoelectric Composite with Microinterfaces for Energy Applications

Area of Science:

• Materials Science
• Nanotechnology
• Energy Harvesting

Background:

• Three-dimensional graphene (3DG) composites offer tunable properties for advanced applications.
• Current synthesis methods for 3DG composites are diverse, with ongoing research into optimizing their performance and fabrication.

Purpose of the Study:

• To develop a novel method for creating 3D graphene sheet (3DGS) and carbon veil (CV) composites (3DGS-CV).
• To characterize the structural, electrical, and thermoelectric properties of the new 3DGS-CV composite.
• To demonstrate the potential applications of the 3DGS-CV composite in thermoelectric power generation and temperature monitoring.

Main Methods:

• Synthesis of 3D graphene sheets (3DGS) via chemical vapor deposition (CVD).
• Fabrication of 3DGS-CV composites by joining 3DGS with commercial carbon veil (CV) using cold rolling.
• Comprehensive characterization including SEM, Raman mapping, XRD, electrical resistance, tensile strength, and Seebeck coefficient measurements.

Main Results:

• Cold rolling facilitated the extrusion of 3DGS into CV pores, creating microinterfaces.
• The extruded 3D graphene maintained its pristine-like characteristics, evidenced by unchanged Raman 2D peak and Seebeck coefficient.
• In-plane thermoelectric devices utilizing p-type 3DGS and n-type CV couples achieved a Seebeck coefficient of 32.5 μV K^-1.
• The 3DGS-CV composite exhibited excellent stability in high relative humidity, unlike many other thermoelectric materials.
• The composite demonstrated a thin, flexible profile with good moisture and thermal stability, suitable for scalable fabrication.

Conclusions:

• The developed cold rolling technique offers a scalable method for producing 3DGS-CV composites with desirable properties.
• The 3DGS-CV composite shows significant potential for thermoelectric power generation due to its tunable properties and stability.
• The material's flexibility, stability, and ease of fabrication make it suitable for practical applications such as temperature monitoring in Li-ion batteries and large-area temperature mapping.