Enhancing the injected electron concentration and thermionic emission property in C12A7:e− ceramic via Al site Zr doping. - Luo, Zhuang; Zhang, Xin; Xiao, Yixin; Liu, Weikang; Han, Shangru; Ju, Shanshan; Liu, Nan; Liu, Yanqin; Lu, Qingmei (Journal of the American Ceramic Society, 2022)