AC Impedence Properties of Multifunction Ceramics ZrScMo2VO12

Alternating current (AC) impedance properties of negative expansion material ZrScMo2VO12 are studied with electrochemical impedance spectroscopy. The conductivity is measured as 2.49×10-4 Ohm-1cm-1K at 673 K and 4.15×10-4 Ohm-1cm-1K at 773 K. We have also elucidated that the conduction of ZrScMo2VO12 come from defects and the co-doping of N and P type in semiconductors. The Schottky defect and Frenkel defect in the material lead to O2- ion conduction, and co-doping leads to electron conduction. And the grain boundary barrier could limit the conduction of electron and hole. This work may be useful for the application exploration of ZrScMo2VO12 in fuel cell and corresponding energy conversion fields.

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

Lithium aluminate, LiAlO2, is a material that is presently being considered as a tritium breeder material in fusion reactors and coating material in Li-conducting electrodes. Here, we employ atomistic simulation techniques to show that the lowest energy intrinsic defect process is the cation anti-site defect (1.10 eV per defect). This was followed closely by the lithium Frenkel defect (1.44 eV per defect), which ensures a high lithium content in the material and inclination for lithium diffusion from formation of vacancies. Li self-diffusion is three dimensional and exhibits a curved pathway with a migration barrier of 0.53 eV. We considered a variety of dopants with charges +1 (Na, K and Rb), +2 (Mg, Ca, Sr and Ba), +3 (Ga, Fe, Co, Ni, Mn, Sc, Y and La) and +4 (Si, Ge, Ti, Zr and Ce) on the Al site. Dopants Mg2+ and Ge4+ can facilitate the formation of Li interstitials and Li vacancies, respectively. Trivalent dopants Fe3+, Ni3+ and Mn3+ prefer to occupy the Al site with exoergic solution energies meaning that they are candidate dopants for the synthesis of Li (Al, M) O2 (M = Fe, Ni and Mn) compounds.

High electrical conductivity in Ba2In2O5brownmillerite based materials induced by design of a Frenkel defect structure

The present work presented a design paradigm for synthesis of Ba2In2O5based materials with both high electrical conductivity and small volume change which are important factors for solid-state device applications.