Selective Dissolution‐Derived Nanoporous Design of Impurity‐Free Bi2Te3 Alloys with High Thermoelectric Performance. Issue 14 (12th January 2023)

• Record Type: Journal Article
• Authors: Lee, Seunghyeok; Jung, Sung‐Jin; Park, Gwang Min; Na, Min Young; Kim, Kwang‐Chon; Hong, Junpyo; Lee, Albert S.; Baek, Seung‐Hyub; Kim, Heesuk; Park, Tae Joo; Kim, Jin‐Sang; Kim, Seong Keun
• Is Part Of: Small. Volume 19:Issue 14(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-01-12
• Subjects: Bi 2Te 3 -- KCl -- porous materials -- selective dissolution -- thermoelectrics; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202205202
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Thermoelectric technology, which has been receiving attention as a sustainable energy source, has limited applications because of its relatively low conversion efficiency. To broaden their application scope, thermoelectric materials require a high dimensionless figure of merit (ZT). Porous structuring of a thermoelectric material is a promising approach to enhance ZT by reducing its thermal conductivity. However, nanopores do not form in thermoelectric materials in a straightforward manner; impurities are also likely to be present in thermoelectric materials. Here, a simple but effective way to synthesize impurity‐free nanoporous Bi0.4 Sb1.6 Te3 via the use of nanoporous raw powder, which is scalably formed by the selective dissolution of KCl after collision between Bi0.4 Sb1.6 Te3 and KCl powders, is proposed. This approach creates abundant nanopores, which effectively scatter phonons, thereby reducing the lattice thermal conductivity by 33% from 0.55 to 0.37 W m −1 K −1 . Benefitting from the optimized porous structure, porous Bi0.4 Sb1.6 Te3 achieves a high ZT of 1.41 in the temperature range of 333–373 K, and an excellent average ZT of 1.34 over a wide temperature range of 298–473 K. This study provides a facile and scalable method for developing high thermoelectric performance Bi2 Te3 ‐based alloys that can be further applied to other thermoelectric materials. Abstract : A simple yet effective approach of selective dissolution of KCl alone after milling an intermixed Bi0.4 Sb1.6 Te3 and KCl powder to create numerous nanopores in Bi2 Te3 ‐based alloys is presented. The nanoporous structure significantly reduces the lattice thermal conductivity by 36%, and this consequently results in high thermoelectric performance (ZTmax : 1.41) without introducing impurities.