Premium
Lithium Doping to Enhance Thermoelectric Performance of MgAgSb with Weak Electron–Phonon Coupling
Author(s) -
Liu Zihang,
Wang Yumei,
Mao Jun,
Geng Huiyuan,
Shuai Jing,
Wang Yuanxu,
He Ran,
Cai Wei,
Sui Jiehe,
Ren Zhifeng
Publication year - 2016
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201502269
Subject(s) - materials science , condensed matter physics , doping , thermoelectric effect , phonon , thermoelectric materials , electrical resistivity and conductivity , phonon scattering , seebeck coefficient , thermal conductivity , optoelectronics , thermodynamics , physics , quantum mechanics , composite material
Despite the unfavorable band structure with twofold degeneracy at the valence band maximum, MgAgSb is still an excellent p‐type thermoelectric material for applications near room temperature. The intrinsically weak electron–phonon coupling, reflected by the low deformation potential E def ≈ 6.3 eV, plays a crucial role in the relatively high power factor of MgAgSb. More importantly, Li is successfully doped into Mg site to tune the carrier concentration, leading to the resistivity reduction by a factor of 3 and a consequent increase in power factor by ≈30% at 300 K. Low lattice thermal conductivity can be simultaneously achieved by all‐scale hierarchical phonon scattering architecture including high density of dislocations and nanoscale stacking faults, nanoinclusions, and multiscale grain boundaries. Collectively, much higher average power factor ≈25 μW cm −1 K −2 with a high average ZT ≈ 1.1 from 300 to 548 K is achieved for 0.01 Li doping, which would result in a high output power density ≈1.56 W cm −2 and leg efficiency ≈9.2% by calculations assuming cold‐side temperature T c = 323 K, hot‐side temperature T h = 548 K, and leg length = 2 mm.