MnO2 was added to 0.75Pb(Zr0.47Ti0.53)O-3-0.25Pb(Zn1/3Nb2/3)O-3 (0.75PZT-0.25PZN) ceramics in order to make a high-power piezoelectric material. The Mn4+ ion produced a defect dipole consisting of an Mn4+ ion and an oxygen vacancy that transformed the 0.75PZT-0.25PZN ceramics into hard materials. The Q(m) value significantly increased with the addition of MnO2 and reached a value of 1680 for the 1.5 mol% MnO2-added 0.75PZT-0.25PZN ceramic. Moreover, this specimen exhibited a high k(p) of 0.53 with a epsilon T-3/epsilon(0) of 1518. Additionally, the 1.5 mol% MnO2-added 0.75PZT-0.25PZN ceramics sintered at 900 degrees C for 4 h also exhibited high piezoelectric properties of Q(m)=1115, k(p)=0.50, and epsilon T-3/epsilon(0)=1537.