Insights into the direct formation of [Ca₂₄Al₂₈O₆₄]⁴⁺(4e⁻) and its electrical characterization

Abstract

C12A7:e− electrides are potentially useful in various technological applications. However, it usually needs to be synthesized through a complicated multistep process under severe conditions. Therefore, the search is on for a more facile and direct process that occurs under milder conditions. Here, a facile and efficient synthesis strategy has been developed for the rapid production of highly conductive C12A7:e− directly from commercially available chemical ingredients of CaO, Al2O3, and Al powders at 1200°C in a 10−2 Pa vacuum for 20 minutes using SPS process. The electron concentration in the as‐prepared C12A7:e− was enhanced up to 2.13 × 1021 cm−3 by simply regulating the addition amounts of Al, covering IM transition. The electronic structure results indicated the formation of homogeneous trapped electrons in the lattice. Further thermal analyses illustrated that Al made a dual function of reducing agent and and reaction promoter, which remarkably reduced the formation temperature of mayenite structure. This study fills in the gaps of direct formation mechanisms of conductive mayenite phase, and provides a new perspective to regulate the resultant Ne.

Electrides: a review

“…Mayenite in the electride form does not always need to be reduced from the mineral form, it can be synthesised directly from commercially available constituents. 42 In fact, there are many different ways of making or activating mayenite, which we summarise in Table 1. However, if one does choose to start from the oxidised form of mayenite and reduce it to the electride form, the material transitions from having an Fig.…”