Energy & Environmental Science
·
2024
·Vol. 17
·期 4
·1416-1425
·
IF 32.4
Jingdan Lei,Hexige Wuliji,Qingyong Ren,Xiaowen Hao,Hongliang Dong,Heyang Chen,Tian-Ran Wei,Jiawei Zhang,Pengfei Qiu,Kunpeng Zhao,Xun Shi
Advanced thermoelectric technology requires high-performance materials with exceptional electrical performance for large power output during service. AB2Sb2-type Zintl phases, especially Mg3Sb2, have attracted great attention recently because of the advantages of high-performance, low-cost and nontoxic components. Currently, remarkably high thermoelectric figures of merit zT values of 1.7–1.9 are reported in n-type Mg3Sb2-based materials, but they are quite low in p-type materials because of the small valence band degeneracy Nv and relatively high band effective mass . Here, we propose a band shaping strategy to effectively enhance the material's electrical transports. Through alloying Zn at the Mg2 sites of Mg3Sb2, double band degeneracy is achieved. Further alloying Yb at the Mg1 sites, band edge effective mass is greatly reduced. Combining the optimized carrier concentration by Li doping, the maximum power factor and zT values are increased to 15.9 μW cm−1 K−2 and 1.4, respectively, superior to those of the vast majority of reported p-type AB2Sb2 Zintl phases. This work demonstrates that band edge shaping is very successful for the optimization of electrical transport and thermoelectric performance in semiconductors.
研究领域:
凝聚态物理
·
材料科学
·
半导体物理
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Zhe Xu,Xiao-Lei Shi,Yibo Zhang,Jisheng Liang,Meng Li,Chengyan Liu,Lei Miao,Siqi Liu,Shihao Wang,Qi Zhou,Jie Gao,Zhongwei Zhang,Wei-Di Liu,Ying Peng,Jun-Liang Chen,Zhi-Gang Chen
Owing to the non-toxicity and low cost, Mg 3 Sb 2 -based Zintls are promising candidates for mid-temperature thermoelectric applications. However, the thermoelectric performance of p-type Mg 3 Sb 2 is significantly lower than that of n-type ones. Here, we achieve simultaneous optimization of the band structure and enhanced phonon scattering through the combined doping of Na at the cation site and Bi at the anion site, leading to a competitive figure of merit, ZT of 0.73 at 773 K and a maximum theoretical energy conversion efficiency of 6.5 % at a temperature difference of 450 K. First-principles calculations indicate that Na and Bi co-doping effectively narrows the band gap and shifts the Fermi level into the valence band, thereby increasing the hole carrier concentration. This ensures a relatively high Seebeck coefficient and improved electrical conductivity, resulting in an excellent power factor of 7.5 µW cm −1 K −2 . Additionally, by adjusting the amount of Bi nanoprecipitates in the matrix, the heterogeneous interfaces significantly enhance phonon scattering and markedly reduce the lattice thermal conductivity (0.52 W m −1 K −1 ), collectively leading to the high thermoelectric performance. Furthermore, by pairing n-type Mg 3.18 Y 0.02 Sb 1.5 Bi 0.49 Se 0.01 , a double-leg thermoelectric device achieves an energy conversion efficiency of 4.1 % with a temperature difference of 390 K.
研究领域:
材料科学
·
热电材料
✓ 已验证
DOI
高影响因子
ACS Applied Energy Materials
·
2024
·
IF 5.4
Chunbo Yang,Xiang Yan,Weiwei Gao,Yang Xia,Hongjie Liu,Liuyi Hu,Wenlong Song,Wenkui Zhang,Xinhui Xia,Hui Huang
Two-dimensional (2D) silicon nanomaterial is a promising anode for lithium-ion batteries (LIBs) due to its large specific area, short ion transport path, and minimized volume expansion. However, its batch utilization is greatly limited by complicated synthesis procedures and time or energy consumption. Herein, we report a facile strategy to construct a kind of Si@C–Fe3O4 lamellar composite with enhanced performance as a LIB anode material. The 2D Si nanosheets are thermally exfoliated from the layered Zintl compound CaSi2 reacting with CO2, followed by surface coating of the C–Fe3O4 layer via the decomposition of ferrocene. Throughout 100 cycles, the as-synthesized Si@C–Fe3O4 composite maintains a stable specific capacity of 1000 mA h g–1 at 0.2 A g–1 with a subtle decay. Compared to 2D Si nanosheets, the composite exhibits better specific capacity and rate capability, particularly at high rates. It is found that C–Fe3O4 is an efficient and low-cost component for enhancing the lithium storage capability of Si-based anodes. We expect that this study will provide a simple and scalable path to the practical fabrication of Si-based anodes toward high-performance LIBs.
研究领域:
材料科学
·
电化学
·
纳米材料
·
能源存储
·
固体化学
·
电池技术
✓ 已验证
DOI
高影响因子
Small
·
2023
·Vol. 20
·期 3
·2306251
·
IF 13.3
Muchun Guo,Ming Liu,Jianbo Zhu,Yuke Zhu,Fengkai Guo,Wei Cai,Yongsheng Zhang,QinYong Zhang,Jiehe Sui
Chemical bonds determine electron and phonon transport in solids. Tailoring chemical bonding in thermoelectric materials causes desirable or compromise thermoelectric transport properties. In this work, taking an example of CaMg 2 Bi 2 with covalent and ionic bonds, density functional theory calculations uncover that element Zn, respectively, replacing Ca and Mg sites cause the weakness of ionic and covalent bonding. Electrically, Zn doping at both Ca and Mg sites increases carrier concentration, while the former leads to higher carrier concentration than that of the latter because of its lower vacancy formation energy. Both doping types increase density-of-state effective mass but their mechanisms are different. The Zn doping Ca site induces resonance level in valence band and Zn doping Mg site promotes orbital alignment. Thermally, point defect and the change of phonon dispersion introduced by doping result in pronounced reduction of lattice thermal conductivity. Finally, combining with the further increase of carrier concentration caused by Na doping and the modulation of band structure and the decrease of lattice thermal conductivity caused by Ba doping, a high figure-of-merit ZT of 1.1 at 823 K in Zn doping Ca sample is realized, which is competitive in 1–2–2 Zintl phase thermoelectric systems.
研究领域:
材料科学
·
凝聚态物理
·
无机化学
·
能源材料
·
热电转换
✓ 已验证
DOI
高影响因子
ACTA MATERIALIA
·
2025
·
IF 9.3
Xiang Wei,Minhui Yuan,Meng Jiang,Huang Gong,Jing Shuai,Jiayi Ye,Lianjun Wang,Qihao Zhang,Wan Jiang
Zintl-phase thermoelectrics with CaAl 2 Si 2 -type structures exhibit desirable “phonon-glass electron-crystal” behavior. However, the development of environmentally friendly p-type counterparts remains challenging. While n-type Mg 3 Sb 2 -based compounds have achieved high figures of merit ( zT > 2.0), their integration with non-Zintl systems is hindered by thermal and chemical mismatches. Moreover, many existing p-type Zintl compounds rely on toxic (Cd, Pb) or scarce (Yb, Ge) elements, restricting their scalability and sustainability. Here, we report a scalable, rare-earth- and toxicity-free p-type Zintl compound, Ca 0.5 Mg 1.297 Ag 0.003 Zn 1.2 Sb 2 , developed via targeted Mg-site substitution. First-principles calculations reveal that Ca substitution at Mg1 sites induces beneficial electronic structure modifications, including bandgap widening, valence band sharpening, and an indirect-to-direct bandgap transition, collectively enhancing carrier mobility (50 cm 2 ·V -1 ·s -1 ) and strengthening carrier-phonon scattering at elevated temperature. Simultaneously, trace Ag doping at Mg2 sites precisely tunes the carrier concentration by nearly one order of magnitude, achieving improved electrical conductivity while maintaining ultralow thermal conductivity. As a result, the optimized compound achieves a peak zT of 0.81 at 773 K and an average zT of 0.50 over 300–773 K. These results demonstrate a chemically stable, sustainable, and high-performing Zintl platform, offering a promising strategy for advancing eco-friendly thermoelectric technologies.
研究领域:
材料科学
·
热电学
·
固体物理
·
能量转换
·
电子结构
✓ 已验证
产品关联
DOI
高影响因子
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