Graphitic carbon nitride nanosheet electrode-based high-performance ionic actuator.

Guan Wu,Cédric Plesse,Ying Hu,Giao T M Nguyen,Wei Chen,Xueli Chen,Jingjing Zhao,Yang Liu,Frédéric Vidal,Vincent Whoehling

doi:10.1038/ncomms8258

Abstract

Ionic actuators have attracted attention due to their remarkably large strain under low-voltage stimulation. Because actuation performance is mainly dominated by the electrochemical and electromechanical processes of the electrode layer, the electrode material and structure are crucial. Here, we report a graphitic carbon nitride nanosheet electrode-based ionic actuator that displays high electrochemical activity and electromechanical conversion abilities, including large specific capacitance (259.4 F g−1) with ionic liquid as the electrolyte, fast actuation response (0.5±0.03% in 300 ms), large electromechanical strain (0.93±0.03%) and high actuation stability (100,000 cycles) under 3 V. The key to the high performance lies in the hierarchical pore structure with dominant size <2 nm, optimal pyridinic nitrogen active sites (6.78%) and effective conductivity (382 S m−1) of the electrode. Our study represents an important step towards artificial muscle technology in which heteroatom modulation in electrodes plays an important role in promoting electrochemical actuation performance.

Highlights

Ionic actuators have attracted attention due to their remarkably large strain under low-voltage stimulation
There has been little substantial progress in elaborating the relation between electrochemical processes to the mechanical bending motion of ionic actuators. This implies that the improvement of the electrochemical activity of carbon electrodes by nitrogen doping and understanding how the nitrogen doping influences the mechanical bending motion of the actuators are necessary to identify the role of electrochemical activation in promoting the development of electrochemical actuation performance
In the present study, motivated by the physicochemical effects caused by nitrogen doping, we develop an ionic actuator based on a hierarchically porous graphitic carbon nitride (g-CN) nanosheet electrode

Summary

Introduction

Ionic actuators have attracted attention due to their remarkably large strain under low-voltage stimulation. Among the various electrochemical actuators, ionic polymer metal composite (IPMC) actuators, which are composed of a layer of polymer electrolyte sandwiched between electrodes, have emerged as promising candidates due to their large actuation deformation and air working stability under low voltage[7,8,9] They store electrical energy in a double interface and convert it into mechanical output by reversible ion intercalation and deintercalation of electrodes[10,11]. The electrodes, including like low-dimensional carbon materials with porous networks, large specific surface areas (SSAs) and high electrical conductivity, which preserve larger capacitance and allow more ion storage, present high-performance electrochemical–mechanical behaviour[12,13,14,15,16]. We believe that our results will play a guiding role in the design of electrochemically active electrode materials to achieve a higher performance electrochemical actuator

Methods

Results

Conclusion