Enhanced energy density and electric cycling reliability via MnO2 modification in sodium niobate‐based relaxor dielectric capacitors

Abstract

Sodium niobate (NaNbO 3 )-based dielectrics have received much attention for energy storage applications due to their low-cost, lightweight, and nontoxic nature. The field-induced metastable ferroelectric phase in NaNbO 3 -based dielectrics, however, leads to a large hysteresis of the polarizationelectric field (P-E) loops and hence deteriorate the energy storage performance. In this study, the hysteresis was successfully reduced by introducing Bi 3+ and Ti 4+ into A-site and B-site of NaNbO 3 , respectively. MnO 2 addition was added to further increase the ceramic density and enhance the cycling reliability. As a result, a high recoverable energy density of 4.3 J/cm 3 and a high energy efficiency of 90% were simultaneously achieved in the ceramic capacitor at an applied electric field of 360 kV/cm. Of particular importance is that the ceramic capacitor exhibits a stable energy storage properties over a wide temperature range of −70 to 170 °C, with much improved electric cycling reliability up to 10 5 cycles.

Excellent Energy Storage Properties Achieved in Sodium Niobate-Based Relaxor Ceramics through Doping Tantalum

“…The parameter τ 0.9 denotes the time needed for discharging 90% of the stored energy, which is 4.28 μs at 300 kV/cm, demonstrating that Ta15 is potential for high-power application. Figure (f) shows the comparison of the energy storage performance between Ta15 and other NN-based relaxor ceramics. − ,− Ta15 exhibits comprehensive energy storage properties with both high W rec and η, which are superior to most of the NN-based relaxors.…”

“…The advantages and disadvantages of the four kinds of typical dielectrics, namely, linear dielectrics (LDs), ferroelectrics (FEs), relaxor ferroelectrics (RFEs), and antiferroelectrics (AFEs), are well summarized in the literature. − Among them, RFEs are considered to process the most comprehensive energy storage properties (both high W rec and high η ), which originates from their high permittivity, slim P - E loop, and medium BDS. , Guided by the regulations restricting the usage of toxic element lead, many researchers paid their attention to the lead-free relaxors for energy storage applications. Most of the studied lead-free relaxor ceramics are based on BaTiO 3 (BT), − (Na 0.5 Bi 0.5 )­TiO 3 (NBT), − BiFeO 3 (BF), − and NaNbO 3 (NN). − However, the η values of some studied ceramics are not high enough (<85%), which may originate from the increased dielectric loss and/or leakage current at the high electric field. The relatively low η indicates the accumulated heat generated by the dissipating energy may be significant during repeated charge/discharge cycles and can somewhat limit the BDS and the device reliability.…”

“…Our previous work showed that the (Na 0.8 Bi 0.1 )(Nb 0.9 Ti 0.1 )O 3 ceramics exhibited typical relaxor characteristics such as diffuse dielectric peaks and slim P-E loops. 20 In this work, Ta 5+ cations were used to substitute the Nb 5+ cations to reduce the dielectric loss and improve the volume resistivity, which was valid and adopted in other niobate ceramics. 26−29 For energy storage applications, the improved volume resistivity of ceramics is expected to benefit both energy efficiency and BDS.…”

A novel relaxor (Bi,Na,Ba)(Ti,Zr)O3 lead‐free ceramic with high energy storage performance

“…36,[46][47][48][49][50][51][52][53][54] The optimized 0.55BNT-0.45BZT ceramic demonstrates a large W rec (=2.62 J/cm 3 ), ultrahigh ƞ (>92%), and excellent thermal stability (<±8%) in a broad temperature span of −30 to 180°C simultaneously, which is much more superior in comparison to those reported lead-free energy storage ceramics such as BaTiO 3 (BT), Bi 0.5 Na 0.5 TiO 3 (BNT), NaNbO 3 (NN), AgNbO 3 (AN) systems etc. 18,46,48,51,52,55 A recently developed 0.65(BNT-BKT)-0.35SBT complex ceramic exhibits an energy storage ability with high W rec of up to 4.06 J/cm 3 (ƞ = 87.3%), while relatively low thermal stability results in a small W rec (~1.71 J/cm 3 ) and ƞ (81.7%) at 160°C. 52 The satisfactory thermal stability for present (1x)BNT-xBZT ceramics could be due to the PNR-dominated relaxations that greatly reduce the extensive diffusion phase transition temperatures and decrease the polarization hysteresis but maintain the large polarization in a broad temperature range.…”

Excellent Energy Storage Performance in NaNbO3-Based Relaxor Antiferroelectric Ceramics Under a Low Electric Field

“…Despite the decreases in P m , W rec increases when 0.025 ≤ x ≤ 0.075 due to the P-E curve becomes slender and long, thereby broadening the integral area and increasing W rec . Such changes in P-E curves caused by the transition from the antiferroelectric P phase to antiferroelectric R phase are helpful to improve the energy storage performance [49][50][51][52]. Subsequently, the W rec and η of NN-BST-xTa ceramics are compared with several representative leadfree ceramics for energy storage reported recently at low E (Fig.…”