An Anionic Framework-Enabled Ion-Anchoring Strategy for Frequency-Tolerant Electrochemical Actuation

and actuator displacement retention. A higher electrostatic potential enables stable operation over a broader frequency range, whereas a lower electrostatic potential reduces stability but yields larger bending displacement, thereby allowing a tunable balance between stability and displacement amplitude to meet diverse application needs. In addition, the actuator maintains stable performance over a relative humidity range of 40-70%, ensuring reliable operation in biofluid-like environments. Notably, the actuator mimics the contraction behavior of the human Achilles tendon and maintains stable, repeatable responses under varied rhythmic conditions, highlighting its potential for next-generation soft robotics.