Enhanced Thermoelectric Properties of WS2/Single-Walled Carbon Nanohorn Nanocomposites

Ji Hoon Kim,Sang Won Lee,Seung-Yong Lee,Keun Soo Kim,Cheol-Min Yang,Seunggun Yu,Yoong Ahm Kim

doi:10.3390/cryst10020140

Abstract

Recently, two-dimensional tungsten disulfide (WS2) has attracted attention as a next generation thermoelectric material due to a favorable Seebeck coefficient. However, its thermoelectric efficiency still needs to be improved due to the intrinsically low electrical conductivity of WS2. In the present study, thermoelectric properties of WS2 hybridized with highly conductive single-walled carbon nanohorns (SWCNHs) were investigated. The WS2/SWCNH nanocomposites were fabricated by annealing the mixture of WS2 and SWCNHs using a high-frequency induction heated sintering (HFIHS) system. By adding SWCNHs to WS2, the nanocomposites exhibited increased electrical conductivity and a slightly decreased Seebeck coefficient with the content of SWCNHs. Hence, the maximum power factor of 128.41 μW/mK2 was achieved for WS2/SWCNHs with 0.1 wt.% SWCNHs at 780 K, resulting in a significantly improved thermoelectric figure of merit (zT) value of 0.027 compared to that of pristine WS2 with zT 0.017.

Highlights

As resources are finite and technologies advance, it is necessary to address issues impacting the global environment and energy to protect environmental degradation and achieve renewable energy [1,2,3]
Thermoelectric WS2 /single-walled carbon nanohorns (SWCNHs) nanocomposites were fabricated by physically mixing two-dimensional
WS2 /SWCNH nanocomposites, the SWCNHs were homogeneously dispersed at the interfaces of the aggregated WS2 flakes without the unnecessary formation of secondary phases

Summary

Introduction

As resources are finite and technologies advance, it is necessary to address issues impacting the global environment and energy to protect environmental degradation and achieve renewable energy [1,2,3]. Thermoelectric materials, which directly convert thermal energy into electrical energy, have been intensively studied. The conversion efficiency of thermoelectric energy is represented by a dimensionless value referred to as the figure of merit (zT) as per the following equation [4]: zT = (σ S2 κ−1 ) T (1). Where σ is the electrical conductivity; S is Seebeck coefficient; κ is thermal conductivity; and T is absolute temperature. Several studies have focused on designing thermoelectric materials based on Crystals 2020, 10, 140; doi:10.3390/cryst10020140 www.mdpi.com/journal/crystals. It is necessary to develop novel thermoelectric materials containing non-toxic earth-abundant elements and achieve superior performance and high thermoelectric efficiency in a wide temperature range

Methods

Results

Conclusion