Investigation on transition behavior and electrical properties of (K0.5Na0.5)1-xLixNb0.84Ta0.1Sb0.06O3 around polymorphic phase transition region

(K0.5Na0.5)1-xLixNb0.84Ta0.1Sb0.06O3 (KNLNTS) lead free ceramics with different Li concentration were fabricated by conventional solid-state reaction method. By increasing Li ions in KNLNTS, the grains grow up and the crystal structure changes from orthorhombic to tetragonal. When 0.03 ≤ x ≤ 0.05, the ceramics structure lays in PPT region. Polarization versus electric field (P-E) hysteresis loops at room temperature show good ferroelectric properties and the remnant polarization decreases by increasing Li content while coercive electric keeps almost unchanged. In PPT region, taking x = 0.04 as an example, the sample shows excellent dielectric properties: the dielectric constant is 1159 and loss tangent is 0.04, while the piezoelectric constant d33 is 245 pC/N and kp is 0.44 at room temperature, it is promising for (K0.5Na0.5)1-xLixNb0.84Ta0.1Sb0.06O3 with 4 at. % Li to substitute PZT.