Directional Confinement Governed Ion Transport for Efficient Actuation

Ionic transport kinetics in electrolytes are a key determinant of ionic actuator performance. Conventional random porous electrolytes are constrained by porosity and tortuosity, leading to an intrinsic limitation in ion mobility within the Bruggeman framework. Here, structural anisotropy is introduced to establish a unified framework that analyzes ion transport from random diffusion to directionally confined regimes. To validate this concept, anisotropic electrolytes with oriented channels are fabricated via directional freeze-drying. These structures exhibit pronounced directional dependence, with through-plane ion mobility twice higher than that of the disordered counterparts, leading to significantly enhanced ionic actuator performance and mitigating the inherent trade-off between strain and blocking force. Moreover, the directional confinement effect is observed across multiple polymer systems, highlighting the critical role of structural anisotropy in regulating ion transport and offering a framework for enhancing electrolyte performance through microstructural design. This strategy enables environmentally robust and stable operation of soft electrochemical actuators for grippers and biomimetic robotics.