High performance lead‐free piezoelectric ceramics are of great importance to the sustainable development of the environment. To obtain excellent comprehensive performance KNN‐based lead‐free piezoelectric ceramics, a lattice distortion strategy combined with domain configuration was designed in (1 − x)K0.5Na0.5Nb0.95Sb0.05O3–xCaHfO3 ((1 − x)KNNS–xCH) system by introduced Ca2+ into the A‐site and Hf4+ into the B‐site. The results demonstrated that the rhombohedral–orthorhombic–tetragonal polymorphic phase boundary (PPB) was constructed in 0.02 ≤ x ≤ 0.04 and significant lattice distortion occurred in R‐ and T‐phase. Moreover, the 0.97KNNS–0.03CH sample exhibited excellent electrical performance (e.g., kp ∼ 43.8%, d*33 ∼ 478.6 pm/V, and d33 ∼ 392 pC/N) together with a high Curie temperature (TC ∼ 295°C) profited from the PPB and domain configurations. The ceramics also showed the optimal thermal stability, which was beneficial to promote the development of KNN‐based ceramics.

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