Rapid Proton‐Transfer‐Induced Alkylamine Functionalization of MXene for High‐Force Electrochemical Actuators

Ti 3 C 2 T x MXene films are promising electrodes for low‐voltage supercapacitor‐like electrochemical actuators (ECAs). However, the little intralayer strain and instability of MXene sheets limit the actuation performance and shelf life of MXene‐based ECAs. Here we demonstrate that hydrophobic alkylamines, such as tetradecylamine (TDA), readily functionalize MXene sheets via a rapid proton transfer reaction within minutes, simultaneously enhancing both the in‐plane actuation strain and stability of the MXene film. The remarkably improved actuation of the TDA‐functionalized MXene film can be attributed to the higher inter‐edge expansion/contraction of hydrophobic TDA‐MXene sheets enabled by the co‐insertion/extraction of protonated TDA (TDAH + ) ions with hydrated lithium ions. The assembled bending ECA can generate a peak‐to‐peak strain difference of 0.997% under a triangular voltage of ±1 V and a blocking force up to 207 times its weight under DC 1 V. Furthermore, the designed soft tweezer can grasp an object of 20.3 times its weight and then hold it securely under 0 V. This study opens a new avenue for developing high‐performance ECAs.