Rapid Photothermal Responsive Conductive MXene Nanocomposite Hydrogels for Soft Manipulators and Sensitive Strain Sensors.

Stimulus-responsive hydrogels are of great significance in soft robotics, wearable electronic devices, and sensors. Near-infrared (NIR) light is considered an ideal stimulus as it can trigger the response behavior remotely and precisely. In this work, a smart flexible stimuli-responsive hydrogel with excellent photothermal property and decent conductivity are prepared by incorporating MXene nanosheets into the physically cross-linked poly(N-isopropyl acrylamide) hydrogel matrix. Because of outstanding photothermal effect and dispersion of MXene, the composite hydrogel exhibits rapid photothermal responsiveness and excellent photothermal stability under the NIR irradiation. Furthermore, the anisotropic bilayer hydrogel actuator shows fast and controllable light-driven bending behavior, which can be used as a light-controlled soft manipulator. Meanwhile, the hydrogel sensor exhibits cycling stability and good durability in detecting various deformation and real-time human activities. Therefore, the present study involving the fabrication of MXene nanocomposite hydrogels for potential applications in remotely controlled actuator and wearable electronic device provides a new method for the development of photothermal responsive conductive hydrogels.

Environment-friendly degradable zinc-ion battery based on guar gum-cellulose aerogel electrolyte.

With the vigorous development of electronics and the increasingly prominent problem of environmental pollution, it is particularly important to exploit environmentally friendly electronic devices. Transient electronics represent a kind of device that once the specified functions have completed can completely or partially disappear through physical or chemical actions. In this work, we introduce a novel guar gum-cellulose aerogel (GCA) membrane based on natural biomaterials and successfully use it as an electrolyte film to fabricate a degradable zinc-ion battery (DZIB). All components of the prepared DZIBs can be successfully degraded or disintegrate in phosphate-buffered saline (PBS) containing a solution of proteinase K after approximately 40 days. This electrolyte film has a high ionic conductivity of approximately 4.73 × 10-2 S cm-1 and a good mechanical stress property. When applied to DZIB, the production of zinc dendrites can be restrained, leading to the battery showing excellent electrochemical performance. The battery exhibits a specific capacity of 309.1 mA h g-1 at a current density of 308 mA g-1 after 100 cycles and a steady cycling ability (100% capacity retention after 200 cycles). More importantly, the electrochemical performance of DZIB is better than that of transient batteries reported in the past, taking a solid step in the field of transient electronics in the initial stage.

Implantable and Biodegradable Micro-Supercapacitor Based on a Superassembled Three-Dimensional Network Zn@PPy Hybrid Electrode.

Transient supercapacitors (TSCs), a new type of advanced supercapacitor (SC) that can completely dissolve with environmentally and biologically benign byproducts in vivo after performing their specified function, have broad application prospects in the fields of green electronics, implantable devices, personalized medicine, military security, and other fields. However, research on TSCs is still in its infancy, and there are still many challenges to be solved, such as the complex preparation process and low energy density. Herein, we report a facile superassembly manufacturing method for an implantable and fully biodegradable three-dimensional network Zn@PPy hybrid electrode by screen printing and electrochemical deposition. The produced superassembled interdigital pseudocapacitor exhibits superior electrochemical performances due to the high capacitances and excellent rate performances of the pattern Zn@PPy electrode and NaCl/agarose electrolyte. An optimized biodegradable SC exhibits a maximum energy density of 0.394 mW h cm-2 and can be fully degraded in vivo in 30 days without any adverse effects in the host organism. This work provides a new platform for transient electronic technology for diverse implantable electronic applications.