Effect of Li-vacancy and Ag-doping on thermoelectric performance of LiCoO2 prepared by spark plasma sintering

Effect of Li-vacancy and Ag-doping on the thermoelectric performance of LiCoO2 has been investigated in this research. Series of Li1−xCoO2 (x = 0, 0.05, 0.1 and 0.2) and Li1−x−yAgyCoO2 (x = 0.05; y = 0, 0.01, 0.02, 0.05) LiCoO2-based bulks with high density have been synthesized by solid-state reaction combined with SPS. The introduction of both Li-vacancy and Ag-doping did not change the main phase structure of LiCoO2, except for little changes of lattice parameters and some second phases. Compared with LiCoO2, both the Li-vacancy and Ag-doping introduced to LiCoO2 have resulted in a significantly enhancement of carrier concentration, thus increasing the electrical conductivity and PF. Due to the enhanced scattering of phonons by the defects introduced by Ag-doing and the Ag second phase by excessive doping, the κ of samples with Li-vacancy reduced. And all samples possessed relative low κ below 4 WK−1m−1 at high temperatures. Finally, Li0.95CoO2 and Li0.93Ag0.02CoO2 respectively got ZT value of 0.065 and 0.18 at 1000 K, nearly three times and six times higher than 0.037 of LiCoO2, indicating that introduction of moderate Li-vacancy and Ag-doping can effectively optimize the thermoelectric performance of LiCoO2-dased materials.

[1]  Gang Chen,et al.  Routes for high-performance thermoelectric materials , 2018, Materials Today.

[2]  Wei Zhang,et al.  Influence of the phase transformation in NaxCoO2 ceramics on thermoelectric properties , 2018, Ceramics International.

[3]  Mofasser Mallick,et al.  Enhancing Thermoelectric Figure-of-Merit of Polycrystalline NayCoO2 by a Combination of Non-stoichiometry and Co-substitution , 2018, Journal of Electronic Materials.

[4]  T. Fang,et al.  In situ deformation and mechanical properties of bismuth telluride prepared via zone melting , 2018 .

[5]  Y. Yoon,et al.  Characterization of LiCoO2/multiwall carbon nanotubes with garnet-type electrolyte fabricated by spark plasma sintering for bulk-type all-solid-state batteries , 2017 .

[6]  Mofasser Mallick,et al.  Giant Enhancement in High-Temperature Thermoelectric Figure-of-Merit of Layered Cobalt Oxide, LiCoO2, Due to a Dual Strategy-Co-Substitution and Lithiation. , 2017, Inorganic chemistry.

[7]  A. Mukhopadhyay,et al.  Spark plasma sintered/synthesized dense and nanostructured materials for solid-state Li-ion batteries: Overview and perspective , 2014 .

[8]  G. J. Snyder,et al.  High thermoelectric figure of merit in heavy hole dominated PbTe , 2011 .

[9]  R. Donelson,et al.  Power factor enhancement in Zn-doped Na0.8CoO2 , 2011 .

[10]  S. Kikkawa,et al.  Impact of lithium composition on the thermoelectric properties of the layered cobalt oxide system LixCoO2 , 2011, 1104.2419.

[11]  Weishu Liu,et al.  High-performance nanostructured thermoelectric materials , 2010 .

[12]  W. S. Liu,et al.  Experimental studies on anisotropic thermoelectric properties and structures of n-type Bi2Te2.7Se0.3. , 2010, Nano letters.

[13]  Ming Wang,et al.  Thermoelectric properties of c-axis oriented Ni-substituted NaCoO2 thermoelectric oxide by the citric acid complex method , 2009 .

[14]  L. Bell.  Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems , 2008, Science.

[15]  M. Jiang,et al.  Na-Site Doping of NaCo2O4 Thermoelectric Materials , 2007 .

[16]  S. Sakurada,et al.  Effect of Ti substitution on the thermoelectric properties of (Zr,Hf)NiSn half-Heusler compounds , 2005 .

[17]  K. Kushida,et al.  Mott-type hopping conduction in the ordered and disordered phases of LiCoO2 , 2004 .

[18]  C. Nan,et al.  Synthesis and thermoelectric properties of (NaxCa1−x)3Co4O9 ceramics , 2003 .

[19]  S. Katsuyama,et al.  Thermoelectric Properties of (Na1‐yMy)xCo2O4 (M: K, Sr, Y, Nd, Sm and Yb; y = 0.01≈0.35). , 2003 .

[20]  Yang Shao-Horn,et al.  Atomic resolution of lithium ions in LiCoO2 , 2003, Nature materials.

[21]  S. Katsuyama,et al.  Thermoelectric properties of (Na1−yMy)xCo2O4 (M=K, Sr, Y, Nd, Sm and Yb; y=0.01∼0.35) , 2003 .

[22]  R. Funahashi,et al.  Exploration of n-type oxides by high throughput screening , 2002, Twenty-First International Conference on Thermoelectrics, 2002. Proceedings ICT '02..

[23]  I. Terasaki.  Transport properties and electronic states of the thermoelectric oxide NaCo2O4 , 2002, cond-mat/0207315.

[24]  Kazuo T. Nakamura,et al.  High-Temperature Thermoelectric Properties of NaxCoO2-δ Single Crystals , 2001 .

[25]  T. Takeuchi,et al.  Thermoelectric properties of spark plasma sintered Ca2.75Gd0.25Co4O9 ceramics , 2001 .

[26]  P. Hagenmuller,et al.  Sur de nouveaux bronzes oxygénés de formule NaχCoO2 (χ1). Le système cobalt-oxygène-sodium , 1973 .

[27]  G. Vineyard,et al.  Semiconductor Thermoelements and Thermoelectric Cooling , 1957 .

[28]  T. Tritt,et al.  Introduction Thermoelectric Phenomena: Background and Applications Thermoelectric Materials, Phenomena, and Applications: a Bird's Eye View Thermoelectric Materials, Phenomena, and Applications: a Bird's Eye View Seebeck and Peltier Effects Definition and Description of the Figure of Merit and Therm , 2022 .