Mechanoelectric transduction based on piezoionic polarization mechanisms diverges from piezoelectric polarization, and is promising for various human-interfaced applications; yet, strategies are urgently demanded to enrich the device design beyond the state-of-the-art d31 mode and also to enhance the electrical outputs. Herein, inspired by the mechanoionic conversion of natural articular cartilage, we realize a d33 piezoionic hydrogel with multi-gradient structure and enhance its output by more than an order of magnitude. The geometry and modulus gradients are designed to amplify the deformation-induced convective ionic current, and the charge gradient is introduced to enlarge the cation-anion transfer rate difference. By synergizing with these three gradients, a multi-gradient piezoionic hydrogel exhibits significantly improved electrical outputs under uniform compression, achieving a d33 coefficient of 27.9 μC N−1. Then, piezoionic hydrogel arrays are fabricated for the demonstration of applications in self-powered electrostimulation-promoted wound healing. Therefore, we present general principles and practical materials-engineering approaches for enhancing piezoionic effect of hydrogels, which will greatly promote its future applications.

中文翻译：

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一种具有生物启发多梯度结构的 d33 压离子水凝胶，用于增强机械离子子转导


基于压离子极化机制的机械电转导与压电极化不同，有望用于各种人机界面应用;然而，迫切需要策略来丰富设备设计，超越最先进的 D31 模式，并提高电气输出。在此，受天然关节软骨机械离子转化的启发，我们实现了具有多梯度结构的 d33 压离子水凝胶，并将其输出提高了一个数量级以上。几何梯度和模量梯度的设计是为了放大变形诱导的对流离子流，并引入电荷梯度以扩大阳离子-阴离子转移速率差。通过与这三个梯度协同作用，多梯度压离子水凝胶在均匀压缩下表现出显着改善的电输出，达到 27.9 μC N-1 的 d33 系数。然后，制造了压离子水凝胶阵列，用于演示在自供电电刺激促进伤口愈合中的应用。因此，我们提出了增强水凝胶压离子效应的一般原理和实用的材料工程方法，这将极大地促进其未来的应用。