Structural and Electric Properties of MnO2-Doped KNN-LT Lead-Free Piezoelectric Ceramics

Abstract

Structural, ferroelectric, dielectric, and piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xmol%MnO2 lead-free piezoelectric ceramics with 0.0 ≤ x ≤ 0.3 were studied. The ceramic samples were synthesized through the conventional solid-state reaction method. The MnO2 addition can reduce the sintering temperature of KNLNT ceramics. Compared with undoped KNLNT ceramic, the piezoelectric measurements showed that piezoelectric properties of K0.5Na0.5NbO3-LiTaO3-xMnO2 were improved (d33 = 251 pC/N) when x = 0.1. In addition, KNLNT-xMnO2 ceramics have larger Pr(20.59~21.97 μC/cm2) and smaller Ec(10.77~6.95 kV/cm), which indicates MnO2 has excellent softening property, which improves the ferroelectric properties of KNLNT ceramics This work adds relevant information regarding of potassium sodium niobate K0.5Na0.5NbO3 (KNN) when doped Li, Ta, Mn at the B-site.

The preparation of MnO2-doped NaNbO3-based lead-free ceramics with enhanced energy storage performance and attractive electrocaloric effect

“…Based on a few researches, some of the Mn 4+ ions can be reduced to Mn 3+ ions stably at high temperatures of 1100 °C-1200 °C. 25) The ionic radius of Mn 4+ (0.53 nm CN = 6) and Mn 3+ (0.65 nm CN = 6) indicated that the dopants were suitable for B-site substitution. The replacement of Nb 5+ (0.64 nm CN = 6) and Mg 2+ (0.72 nm CN = 6) led to a movement to higher 2θ angles.…”

“…22) Usually, high W rec of lead-free ceramics is always induced by the application of large electric field, which depends on some factors including the existence of second phase, grain size and porosity. 23,24) Thus, apart from chemical modification, sintering aids are attractive to improve electrical properties, which can decrease sintering temperature to inhibit the volatility of alkaline elements, such as MnO 2 , 25,26) CuO 27,28) and NiO. 29,30) MnO 2 is not only an effective sintering aid for densification, but an acceptor dopant for improving electrical properties.…”

Achieving excellent mechanical and electrical properties in transition metal oxides and rare earth oxide‐doped KNN‐based piezoceramics

“…26 Deng et al reported that the addition of MnO 2 can enhance the piezoelectric properties and increase the density of KNN-based ceramics. 27 Li et al simultaneously introduced ZnO and CuO into KNN-based ceramics, 28 and found that the mechanical quality factor Q m was significantly improved from 82 to 427 and dielectric loss tan δ was markedly decreased from 2.46% to 0.64%. Another frequently utilized dopant in KNN-based ceramics is rare earth oxide, which can modify the photoluminescence properties, inhibit growth of grains, and also improve the piezoelectric performance.…”

“…Deng et al. reported that the addition of MnO 2 can enhance the piezoelectric properties and increase the density of KNN‐based ceramics 27 . Li et al.…”

Weakening Effect of Mn on the Oxygen Vacancies of KNN-BZT-Mn Ceramic with Improved Energy Storage Performance

“…Furthermore, the MnO 2 with appropriate content is conducive to the improvement of sintering and energy storage properties of KNN-based ceramics in some reported research. 24,25 Therefore, in this work, the MnO 2 is added in 0.85K 0.5 N 0.5 NbO 3 −0.15BiZn 0.5 Ti 0.5 O 3 ceramic and 0.1 mol% MnO 2 is designed based on our preliminary experiment. The corresponding energy storage performances are investigated to address the mechanism of performance enhancement.…”