Enhanced figure of merit in La0.95Sr0.05CoO3/Ag nanocomposites

Insights into the Classification of Nanoinclusions of Composites for Thermoelectric Applications

“…The concentration of the nanoinclusions should be calculated to an optimum level such that the composite should have a negotiable effect on electrical transport and a maximum impact on reducing κ . Nanoinclusion concentrations around 5–6 wt % are estimated as optimized to form uniform dispersoids around the grain boundaries and form into a composite structure with maximum TE performance. , For example, adding 3 vol % Ag nanoinclusions in the oxide matrix increases the κ twice and reduces the overall ZT . With the increasing nanoinclusion concentration, their corresponding inclusion size also increases, negatively affecting the material ZT , that is, reducing the mean free path of the electrons and the PF .…”

“…However, the distribution of nanoinclusions also affects their mechanical properties as finely dispersed nanoinclusions have more significant reinforcement and strengthening properties . However, the sintering temperature plays a crucial role in distributing the nanoinclusions such as inclusion growth, clustering, or fine dispersion; therefore, controlling the sintering time, temperature, and rate signifies the distribution of the nanoinclusions. ,, …”

“…The size and shape of the metallic nanoinclusions affect the energy filtering effect . The composite’s enhanced κ is due to the electron thermal conductivity contribution from the metallic nanoinclusions. ,,, Metallic inclusions such as Cu, ,, Fe, , Zn, , B, Pt, Ag, ,,,, Bi, , Au, W, Si, ,, Sn, Ge, Yb, Te, and In , were used to improve the thermoelectric properties.…”

“…58,59 For example, adding 3 vol % Ag nanoinclusions in the oxide matrix increases the κ twice and reduces the overall ZT. 24 With the increasing nanoinclusion concentration, their corresponding inclusion size also increases, negatively affecting the material ZT, that is, reducing the mean free path of the electrons and the PF. 52 The addition of a high concentration of nanoinclusions causes an agglomerate at the grain boundaries during sintering and has detrimental effects on the thermoelectric performance.…”

“…Phonon scattering strongly occurs when the phonon wavelengths are comparable to the nanoparticles’ size, which would play a vital role because in this range the phonon frequencies typically cannot be effectively scattered by either point defects or grain boundaries . Nanoinclusions-associated interface boundaries scatter high-frequency phonons, whereas the induced structural defects and fine grain boundaries scatter short- and mid-frequency phonons, respectively. , Advantageously, these nanoinclusions also act as back stress points during densification, which makes some percentage of enhancement in porosity as compared to pristine materials, that is also attributed to the reduced κ. − …”