An ionotronic device functions by a hybrid circuit of mobile ions and mobile electrons. Hydrogels are stretchable, transparent, ionic conductors that can transmit electrical signals of high frequency over long distance, enabling ionotronic devices such as artificial muscles, skins and axons. Moreover, ionotronic luminescent devices, ionotronic liquid crystal devices, touchpads, triboelectric generators, artificial eels and gel–elastomer–oil devices can be designed based on hydrogels. In this Review, we discuss first-generation hydrogel ionotronic devices and the challenges associated with the mechanical properties and the chemistry of the materials. We examine how strong and stretchable adhesion between hydrophilic and hydrophobic polymer networks can be achieved, how water can be retained in hydrogels and how to design hydrogels that resist fatigue under cyclic loads. Finally, we highlight applications of hydrogel ionotronic devices and discuss the future of the field.

电离电子器件通过移动离子和移动电子的混合电路来工作。水凝胶是可拉伸的，透明的离子导体，可以在远距离传输高频电信号，从而使诸如人造肌肉，皮肤和轴突等离子电子设备成为可能。此外，可以基于水凝胶设计离子电致发光设备，离子电致液晶设备，触摸板，摩擦发电机，人造鳗鱼和凝胶-弹性体-油设备。在这篇评论中，我们讨论了第一代水凝胶离子电子设备以及与材料的机械性能和化学性质相关的挑战。我们研究了亲水性和疏水性聚合物网络之间如何实现牢固而可拉伸的粘合，如何将水保留在水凝胶中以及如何设计在周期性载荷下抵抗疲劳的水凝胶。最后，我们重点介绍了水凝胶离子电子设备的应用，并讨论了该领域的未来。