Argyrodites with a general chemical formula of A 8 BX 6 (A = Cu, Ag; B = Si, Ge, Sn; and X = S, Se, and Te) are known for the intimate interplay among mobile ions, electrons, and phonons, which yields rich material physics and materials chemistry phenomena. In particular, the coexistence of fast ionic conduction and promising thermoelectric performance in

An alternative strategy to create optimum band shape for superior thermoelectric performance by utilizing stereochemically active lone pair electrons is proposed, which has been demonstrated in the Ag6Ge10(1−x)Ga10xP12.