High‐Performance Hierarchical Black‐Phosphorous‐Based Soft Electrochemical Actuators in Bioinspired Applications

Abstract

Bioinspired methods allowing artificial actuators to perform controllably are potentially important for various principles and may offer fundamental insight into chemistry and engineering. To date, the main challenges persist regarding the achievement of large deformation in fast response‐time and potential‐engineering applications in which electrode materials and structures limit ion diffusion and accumulation processes. Herein, a novel electrochemical actuator is developed that presents both higher electromechanical performances and biomimetic applications based on hierachically structured covalently bridged black phosphorous/carbon nanotubes. The new actuator demonstrates astonishing actuation properties, including low power consumption/strain (0.04 W cm−2 %−1), a large peak‐to‐peak strain (1.67%), a controlled frequency response (0.1–20 Hz), faster strain and stress rates (11.57% s−1; 28.48 MPa s−1), high power (29.11 kW m−3), and energy (8.48 kJ m−3) densities, and excellent cycling stability (500 000 cycles). More importantly, bioinspired applications such as artificial‐claw, wings‐vibrating, bionic‐flower, and hand actuators have been realized. The key to high performances stems from hierachically structured materials with an ordered lamellar structure, large redox activity, and electrochemical capacitance (321.4 F g−1) for ions with smooth diffusion and flooding accommodation, which will guide substantial progress of next‐generation electrochemical actuators.

High‐Performance Ionic‐Polymer–Metal Composite: Toward Large‐Deformation Fast‐Response Artificial Muscles

“…After the voltage was switched on, the IPMC rapidly bent to the largest angle with a rapid increase in current across the sample, originated from the fast charge of the electric double layer. The further ion diffusion into the electrode networks was combined with a gradual decrease in current, which provided a high actuation performance …”

“…Jho et al have fabricated ultrathick ion‐exchange membranes by hot‐pressing stacked Nafion films, which can improve the output forces of the IPMC actuators . On the other hand, novel electrode materials and fabrication methods were investigated to improve the conductivities and stabilities of the electrode layers so that the IPMC actuators can respond faster and operate longer . For example, metal electrodes fabricated by electroless plating instead of electroplating usually exhibit higher conductivities owing to the dense structures of the metal nanoparticles produced by the gradual electroless plating .…”

Hierarchical Micro‐Mesoporous Carbon‐Framework‐Based Hybrid Nanofibres for High‐Density Capacitive Energy Storage

“…With the rapid development of portable electronic devices and the electronic needs of new smart applications, [1] the ability to exploit high-performance flexible energy-storage materials to steadily power electronic devices is highly desirable. [2] Particularly,h ighlighting the innovative characteristics of wearable,s elf-powered, and deformable energy supplies are of significance.A mong various flexible energy storage materials,f lexible supercapacitors (FSCs), especially those fibre-assembled FSCs (FFSCs) have emerged as promising candidates because of their higher power density, faster charge/discharge rate, [1b, 3] longer cycling life, [4] together with lightweight, [5] high weavability [6] and larger deformable compatibility.…”

Recent Advances in Chemical Functionalization of 2D Black Phosphorous Nanosheets

“…For covalent functionalization, improving the selectivity (e.g., edges or defects or certain sites/domains selectively functionalized, Figure ), will hold the potential to precisely control the properties of BPNSs. On the other hand, building functionalized BPNSs based 3D hierarchical nanostructures can be a useful way to prevent the aggregation of BPNSs and thus the properties of BPNSs can be fully utilized (Figure ) . Further issues regarding to how the charge transfer happens and how the charges are spatially distributed between BPNSs and functional units, still need to be fully understood at the fundamental level …”