Hydrogels have been widely used for various applications, and thus addressing the challenges associated with the design of sustainable hydrogels has become an important issue. However, little attention has been devoted toward the design of crosslinkers which are often toxic, lack self-healing capabilities, and derived from petrochemicals. Herein, novel cyclodextrin topological nanoparticles (TNPs) have been constructed. These TNPs were found to possess crosslinking capabilities and the corresponding TNPs-crosslinked hydrogels showed excellent mechanical performances with a high stretchability of 1860 % and stress of 180 kPa and good anti-fatigue abilities. These hydrogels could be readily recycled and used for modular assembly and disassembly in various shapes and could serve as flexible strain sensors to monitor human activities with a sensing range of 0-1800 %, controllable sensitivity, and good fatigue resistance. These topological nanoparticles can inspire the design of novel physical crosslinkers for novel flexible strain sensors, tough and self-healing hydrogels, and soft robotics.

The development of transparent and flexible sensors suitable for the full-range monitoring of human activities is highly desirable, yet presents a daunting challenge due to the need for a combination of properties such as high stretchability, high sensitivity, and good linearity. Gradient structures are commonly found in many biological systems and exhibit excellent mechanical properties. Here, we report a novel surface-confined gradient conductive network (SGN) strategy to construct conductive polymer hydrogel-based stain sensors (CHSS). This CHSS showed an ultrahigh stretchability of 4000% strain, transparency above 90% at a wavelength of 600 nm, as well as skin-like Young's modulus of 40 kPa. Impressively, the sensitivity was improved to 3.0 and outstanding linear sensing performance was achieved simultaneously in the ultrawide range of 0% to 4000% strain with a high R-square value of 0.994. With the help of SGN strategy, this CHSS was able to monitor both large-scale and small-scale human motions and activities. This SGN strategy can open a new avenue for the development of novel flexible strain sensors with excellent mechanical, transparent, and sensing performance for full-range monitoring of human activities.

Flexible solid-state rechargeable batteries have attracted extensive attention for their potential to accommodate the deep integration of humans and flexible electronics. To achieve a wide operating temperature range of -20 to 70 degrees C as well as good flexibility and safety, a novel flexible and rechargeable solid-state aqueous Zn-air battery was developed and is reported herein. This battery possessed temperature-resistance, long-term stability, excellent flexibility and mechanical properties, low interfacial resistance, and good safety. The Zn-air battery exhibited a power density of 11.8 mW cm(-2), a specific capacity of 663.25 mA h g(-1), and a gravimetric energy density of 769.37 W h kg(-1) at 1 mA cm(-2). and 25 degrees C. During operation at 0 and -20 degrees C, the maximum output power density retentions of the battery were 80.13% and 67.87%, respectively, compared with that at 25 degrees C. Furthermore, the battery could consistently power a timer under various conditions, including temperatures of -30 and 70 degrees C as well as exposure to the flame of an alcohol burner and being subjected to impacts, cutting, or bending. Notably, the battery was able to operate in these scenarios without developing smoke and blast phenomena, thus demonstrating that this battery has significant potential for future applications in safely wearable and flexible electronics that could be employed in harsh temperature environments. These applications would have relevance in a wide variety of fields, such as electric vehicles, aerospace technology, and the military.

A controllable Co doping strategy is introduced to significantly activate more catalytic sites for Mn-based materials and anchor Co-Mn nanoparticles on the N-doped carbon nanotube (N-CNT) substrates. The as-synthesized CoMn2O4/N-CNTs exhibit excellent ORR catalytic performance with large limited current density and positive half-wave potential, even outperforming the Pt/C catalysts. The outstanding ORR activity allows the CoMn2O4/N-CNTs to directly serve as the cathode electrode in a liquid/solid state Zn-air battery, demonstrating large power density and robust stability.