Investigation of the thermoelectric properties of La2CuO4 ceramics with the addition of Ag

Thermoelectric properties of polycrystalline La 2 CuO 4 with (x = 0.0, 0.02, 0.05, 0.10, 0.15, 0.20) have been examined. For this, the samples have been synthesised via solid-state reaction (SSR) technique. For microstructural analysis of investigated pellets, X-ray diffraction and scanning electron microscopy have been performed. The electrical resistivity and Seebeck coefficient of the investigated samples have been measured with the help of an in-house fabricated setup, capable to measure the resistivity and thermopower between 100 and 400 K with ±3% experimental uncertainty. The electrical resistivity reveals a semiconducting nature for pristine pellets. However, a transition to metallic nature of electrical resistivity is observed for Sr doping concentration ≥ 0.02. The Seebeck coefficient (S) of investigated pellets is found to be positive, which indicates holes type conduction. Apart from that, a gradual decrease in the Seebeck coefficient has also been noticed as Sr dose increases. Again, the sample with Sr concentration x = 0.02 is found to be the best with a maximum power factor value (6.947 μW/cm K 2 ) at 165 K, which is a positive sign for future applicability of LSCO-based oxide materials for energy harvesting applications below room temperature.

Section: Resultssupporting

confidence: 65%

β \cos θ = \frac{italickλ}{D} + ε (4 \sin θ),

where k is the shape factor and β is the full width at half maxima.…”

Section: Resultsmentioning

confidence: 60%

Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

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Thermoelectric properties of Sr‐doped LSCO for energy harvesting applications below room temperature

Saif

Tripathi

2022

Thermoelectric properties of La_1.96Sr_0.04CuO₄ for energy harvesting and storage applications

Saif,

Tripathi

2023

The polycrystalline pellet of La2‐xSrxCuO4 with x = 0.04, has been sintered using the solid‐state reaction process. X‐ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) have been carried out for microstructural characterizations. The transport properties (electrical and thermal) of La2‐xSrxCuO4 for x = 0.04 have been investigated in the temperature range between 15 and 300 K with the aid of a closed‐cycle refrigerator (CCR). The DC four‐probe resistivity measurement confirms a decrease in resistivity with increasing temperature below 200 K. However, above 200 K, an increase in resistivity with temperature (metallic behaviour) has been noticed due to charge carrier localization. The Hall measurement conveys hole‐type conduction and phonon‐dominated mobility with carrier concentration ~1018/cm3, which lie somewhere between non‐degenerate and degenerate limit. The Seebeck coefficient also confirms hole type conduction and its temperature dependence can be explained in the light of the model applicable for mixed‐valence heavy fermions systems. The steady‐state method for thermal conductivity measurement has been employed. The plot of thermal conductivity (λ) as a function of temperature (T) shows a hump‐like structure at around 65 K, which may be attributed to an increase in the quasi‐particle mean free path. Further, the electronic and lattice (phononic) contributions to thermal conductivity have been separated using electrical conductivity data with the help of the Wiedemann‐Franz law. Our analysis confirms the phononic dominance in the thermal conductivity of the investigated sample. The figure of merit (ZT) estimated from the experimental data has a maximum value of 0.086 at 290 K and hence shows its inherent energy harvesting properties that can further be stored in a battery or capacitor.

Enhanced Thermoelectric Performance of La_1.98Sr_0.02Cu_0.94Co_0.06O₄ by Multiwalled Carbon Nanotubes Addition

Saif,

Tripathi

2024

Effect of multiwalled carbon nanotubes (MWCNTs) addition on thermoelectric properties of polycrystalline LSCCO (La1.98Sr0.02Cu0.94Co0.06O4) has been examined. The samples have been synthesized via the solid‐state reaction technique. Micro‐structural and surface morphology of the synthesized pellets have been investigated using X‐ray diffraction and Field Emission Scanning Electron Microscopy, respectively. The electrical resistivity and Seebeck coefficient of investigated pellets have been measured using a custom‐built apparatus between 300 and 450 K. Nevertheless, the transient heat transfer technique has been adopted for thermal conductivity measurement. The addition of MWCNTs significantly enhances the electrical conductivity and reduces the thermal conductivity of LSCCO. This results in a remarkable improvement in the figure of merit in spite of the reduction in Seebeck coefficient with MWCNTs addition. The maximum ZT value ~0.07 is achieved at 323 K for 0.05 wt% MWCNTs‐loaded LSCCO, which is ~28 times that of pristine LSCCO. The enhanced thermoelectric performance is attributed to the increased carrier concentration, reduced grain size, and improved interface phonon scattering due to MWCNTs addition. Our results demonstrate the potential of MWCNTs as an effective additive to enhance the thermoelectric properties of LSCCO‐based materials.