Construction of MXene interlayer conductive ion transport channel by polypyrrole-coated cellulose nanofibers for ultralow voltage high-performance ionic soft actuators

Ionic soft actuators are extensively utilized in soft robotics and intelligent flexible devices due to their low-voltage actuation capability. MXene(Ti3C2Tx) has potential value as an electrode material for ionic soft actuators owing to its high conductivity and large specific surface area. However, the actuation performance of its ionic soft actuator is limited by poor extensibility and low capacitance caused by the stacking effect. Here, a high-performance ionic soft actuator with MXene\polypyrrole-coated cellulose nanofibers (CNF@PPy) is reported. While gaining high flexibility of the electrode due to the great mechanical property of CNF, the fast conductive transport channel is constructed by doping CNF@PPy between MXene layers, which not only effectively reduces the loss of conductive properties and drastically improves the ion migration rate, but also prevents MXene from stacking and has additional chemical active sites, significantly increasing its ion storage capacity. Consequently, the actuator exhibits excellent actuation performance at the 0.5 V ultralow voltage: 0.79 % bending strain, 6 s rapid response, and 91.03 % high durability after 5 hours. Additionally, the potential for the actuating core of advanced flexible electronic devices is demonstrated by the application of flexible forceps and the flexible electronic eye. •MXene interlayer conductive ion transport channels are constructed by CNF@PPy.•CNF@PPy can reduce the loss of conductivity and increase the ion migration rate.•CNF@PPy can prevent the stacking of MXene and improve their ion storage capacity.•High actuation performance of the MXene/CNF@PPy actuator at ultralow voltages has been exhibited.