Electronic and Thermoelectric Properties of V2O5, MgV2O5, and CaV2O5

Abstract

Developing new thermoelectric materials with high performance can broaden the thermoelectric family and is the key to fulfill extreme condition applications. In this work, we proposed two new high-temperature thermoelectric materials—MgV2O5 and CaV2O5—which are derived from the interface engineered V2O5. The electronic and thermoelectric properties of V2O5, MgV2O5, and CaV2O5 were calculated based on first principles and Boltzmann semi-classical transport equations. It was found that although V2O5 possessed a large Seebeck coefficient, its large band gap strongly limited the electrical conductivity, hence hindering it from being good thermoelectric material. With the intercalation of Mg and Ca atoms into the van der Waals interfaces of V2O5, i.e., forming MgV2O5 and CaV2O5, the electronic band gaps could be dramatically reduced down to below 0.1 eV, which is beneficial for electrical conductivity. In MgV2O5 and CaV2O5, the Seebeck coefficient was not largely affected compared to V2O5. Consequently, the thermoelectric figure of merit was expected to be improved noticeably. Moreover, the intercalation of Mg and Ca atoms into the V2O5 van der Waals interfaces enhanced the anisotropic transport and thus provided a possible way for further engineering of their thermoelectric performance by nanostructuring. Our work provided theoretical guidelines for the improvement of thermoelectric performance in layered oxide materials.

Mn0.26V2O5·nH2O Nanoribbons with Fast Ion Diffusion Channels and High Electrical Conductivity for Intercalation Pseudocapacitive Zn2+ Storage

“…As shown in Figure S4, a mixture state of Mn 2+ and Mn 3+ suggests that part of Mn 2+ was oxidized to Mn 3+ by V 5+ , which can greatly improve the electrical conductivity of MVOH-2 due to the Mn doping effect as noted in the recent study . The four-point probe shows that the conductivity of MVOH-2 is 633.2 S m –1 , much higher than those of Zn 0.25 V 2 O 5 ·0.85H 2 O (46 S m –1 ) and Ca 0.24 V 2 O 5 ·0.83H 2 O (185 S m –1 ), as well as commercial V 2 O 5 (∼10 –2 S m –1 ) . The high conductivity will accelerate the electron transfer from the electrode to the external circuit, thereby boosting the kinetics of MVOH-2.…”

Interplay of Thermal and Electronic Effects in the Mott Transition of Nanosized VO2 Phase Change Memory Devices

“…For the metal electrodes we used the built-in values of κ Au = 311W/mK and κ Ti = 21.9W/mK for the thermal conductivity and σ Au = 45.6 · 10 6 S/m and σ Ti = 2.6 · 10 6 S/m for the electrical conductivity. In case of the V 2 O 5 layer, σ normalV 2 normalO 5 = 0.04 S/m value was taken from the literature, whereas the electrical conductivity of the VO 2 layer was deduced from the experimental R–T curve (see Figure e). The COMSOL simulations were performed with 2, 3, 5, and 10 nm grid size in the active region, yielding less than 0.5% difference in the simulated current and temperature values.…”

“…S/m value was taken from the literature, 63 whereas the electrical conductivity of the VO 2 layer was deduced from the experimental R−T curve (see Figure 2e). The COMSOL simulations were performed with 2, 3, 5, and 10 nm grid size in the active region, yielding less than 0.5% difference in the simulated current and temperature values.…”

Recent Achievements in Experimental and Computational Studies of Positive Electrode Materials for Nonaqueous Ca- and Al-Ion Batteries

“…The high band gap thus leads to low electronic conductivity. Cation doping in V 2 O 5 shifts the Fermi levels to higher energy and midgap states because of the electron transfer from the cation to V 2 O 5 , which enhances the electronic conductivity. , …”