[Ca24Al28O64]4+(4e-) are directly and quickly synthesized by self-reduction of C12H10Ca3O14 + Al2O3 without any reducing agent

C12H10Ca3O14 + Al2O3 powders are used as precursors, and the dense [Ca24Al28O64](4+)(4e(-)) (C12A7:e(-)) ceramic block with high electron density is quickly synthesized in one step under a spark plasma sintering (SPS) process with a temperature of 1000 degrees C and a time of 5 minutes. The microstructure and composition analysis results show that the synthesized C12A7:e(-) is dense (99.7%), has no defects, and no impurities are introduced. The electronic structure analysis results show that the electron concentration of the sample is 2 x 10(21) cm(-3). This method realizes the self-reduction of the sample through the CO gas generated during the sintering process, avoids the introduction of impurities, and dramatically simplifies the process. These results provide a potential path for the rapid fabrication of a large number of C12A7:e(-) with high electron concentration and provide a basis for its practical applications such as cold cathode fluorescent lamp and catalyst carrier.