Study on the Thermal Conductivity of Mannitol Enhanced by Graphene Nanoparticles for Thermoelectric Power Generation

Abstract

The existing thermoelectric materials are greatly affected by the temperature environment, which can provide better power output in a stable temperature environment by using composite phase change material with enhanced heat conduction. The graphene is dispersed in the liquid mannitol to make the nanomixed material. Test results show that the thermal conductivity of mannitol increased from 0.7 Wm-1 K-1 to 2.07 Wm-1 K-1, 179.73% times as much. The effective thermal conductivity of mannitol can be increased to 8.4236 Wm-1 K-1 by using a graphite foam with a porosity of 0.9. After adding 1 wt.% and 5 wt.% graphene particles, the effective thermal conductivity increased to 8.73 Wm-1 K-1 and 9.63 Wm-1 K-1, respectively. The simulation results in a large heat source environment show that mannitol with improved thermal conductivity can ensure the stable operation of the thermoelectric material in the optimal temperature environment for 120 s, and the open-circuit voltage is maintained at about 6.5 V in that time.