Electrical Energy Storage from Low-Grade Heat Using Reduced Graphene Oxide-Carbon Nanotube Composite Materials

Area of Science:

• Materials Science
• Energy Harvesting
• Nanotechnology

Background:

• Low-grade heat conversion to electricity is crucial for energy efficiency.
• Nanoporous carbon materials offer promising thermoelectric properties.
• Developing advanced materials for thermal energy harvesting is an active research area.

Purpose of the Study:

• To synthesize and characterize a reduced graphene oxide (RGO) and carbon nanotube (CNT) composite for thermoelectric applications.
• To investigate the thermoelectric performance of the RGO-CNT composite in a symmetrical thermoelectric cell.
• To evaluate the impact of CNT content and KCl concentration on thermoelectric properties and energy conversion efficiency.

Main Methods:

• Synthesis of a reduced graphene oxide and carbon nanotube composite with a microporous structure.
• Construction of a symmetrical thermoelectric cell for thermal energy harvesting.
• Measurement of thermoelectric voltage, internal resistance, and capacitance under varying temperature differences and KCl concentrations.

Main Results:

• The RGO-CNT composite exhibited a linear relationship between temperature difference and generated voltage.
• Thermoelectric performance significantly improved with increasing CNT content.
• A maximum thermoelectric coefficient of 4.17 mV/°C was achieved with 0.1 M KCl and RGO-5%CNTs.
• CNT incorporation reduced internal resistance and increased equivalent capacitance, enhancing discharge power and efficiency.

Conclusions:

• The RGO-CNT composite demonstrates superior thermoelectric performance compared to pure RGO.
• CNT content is a key factor in optimizing thermoelectric properties for efficient thermal energy harvesting.
• The developed composite holds potential for practical applications in converting low-grade heat into storable electrical energy.