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Morphogenesis, commonly found in leaves, [1-3] flowers, [4,5] cones, [6] seed pods [7,8] and other biological systems, is typically driven by differential growth, swelling, or shrinkage [6,9,10] that occurs within multilayered components of species. For example, the opening and closing of pine cones are attributed to the tissue's self-bending, which undergoes three states of humidity-driven deformation. [6] As these morphological changes in nature result from the variation of the surrounding environment, it is desirable to mimic these natural examples to fabricate multilayered structures that can spontaneously respond to various external stimuli, such as temperature, pH, biochemical enzymes, magnetic fields, and solvent composition, [11-14] which can find a variety of applications, such as semiconductor nanotubes, [15-18] soft robotics, [19-22] snapping surface, [23] and micro/ nanoelectromechanical systems. [24-26] For a multilayer structure, the misfit strain across layers can lead to some interesting phenomena such as multistability, where more than one stable state exists with the same boundary conditions or control parameters of the system. One specific case is called neutral stability, in which the system can stay stable at each point in a continuous path of shape change. In such a case, the system is said to have zero stiffness because the potential energy of the system keeps unchanged during the shape change and theoretically no external force is needed. Various cases that incorporate neutrally stable (zero stiffness) systems have been studied. Guest et al. [27,28] discovered neutral stability of a heated copper beryllium strip, the shape of which depended on the residual stresses. The strip has zero stiffness for finite deformation along

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Ceramic‐based dielectric capacitor are highly suitable for pulsed power applications due to their high power density and excellent reliability. However, the ultrahigh applied electric field limit their applications in integrated electronic devices. In this work, (1−x){0.96(Bi0.5Na0.5)(Ti0.995Mn0.005)O3‐0.04BiAlO3}‐xNaNbO3 (BNT‐BA‐xNN, x = 0, 0.04, 0.08, 0.12, and 0.16) ternary ceramics were designed to achieve excellent energy storage properties. It was found that the introduction of NaNbO3 (NN) effectively increase the difference (ΔP) between Pmax and Pr, resulting in an obvious enhancement of the energy storage properties. High recoverable energy storage density, responsivity, and power density, that is, Wrec = 2.01 J/cm3, ξ = Wrec/E = 130.69 J/(kV⋅m2), and PD = 25.59 MW/cm3, accompanied with superior temperature stability were realized at x = 0.14 composition. In addition, the thermal stable dielectric properties of the sample can be prominently improved with increasing NN content. The temperature coefficient of capacitance (TCC) of x = 0.16 composition is lower than 15% over the temperature range from 49°C to 340°C, with a high dielectric permittivity of 1647 and a low dielectric loss (0.0107) at 150°C. All these features show that the BNT‐BA‐xNN ceramics are promising materials for energy storage application.

Bi 0.5 Na 0.5 )TiO 3 (BNT)-based ferroelectric ceramics have drawn extensive attention because of their excellent electrical properties and interesting depolarization behavior. However, the poor thermal stability of electrical properties limits their practical application. In this work, the effect of sintering temperature (T s ) on the depolarization behavior of BNT-based ceramics was systematically investigated. It is found that the depolarization temperature T d determined from pyroelectric measurement tends to decrease with increasing T s , which indicates that lower T s defers the ferroelectricrelaxor (FE-RE) phase transition. However, for the samples sintered at higher T s (such as 1180°C), although the T d is reduced, the thermal stability is better compared with the sample sintered at lower T s (1100°C) because the diffuse behavior of the FE-RE phase transition is suppressed. According to these results, we propose that the thermal stability of electrical properties for BNT-based ceramics is not only related to high T d , but also to the diffuse degree of phase transition. K E Y W O R D Sbismuth titanates, ferroelectricity/ferroelectric materials, lead-free ceramics 1 | INTRODUCTION (Bi 0.5 Na 0.5 )TiO 3 (BNT)-based ferroelectric ceramics have drawn extensive attention because of their large polarization, giant electro-strain, excellent energy storage performance, and interesting depolarization behavior. [1][2][3][4][5][6] Since BNT-based ceramics have made great progress in electrical properties in recent decades, BNT-based ceramics are considered to How to cite this article: