Regenerated hydrogel electrolyte towards an all-gel supercapacitor

Electrolyte regeneration is an important goal for environmental protection and sustainable development efforts.Herein,we report a facile strategy inspired by the transformation of edible dough from flour to regenerate hydrogel electrolytes from their dehydrated copolymer granules(CGs)via direct addition of water or salt solution.With the aid of heating,this procedure is efficient,relatively quick,and easily implemented.The dehydrated CGs are lightweight,reusable and stable under long-term storage.Even after 5 cycles of dehydration and regeneration,the regeneration efficiency of the hydrogel electrolytes,as evaluated based on retention of mechanical strength,is over 60%.The regenerated electrolytes possess considerable ionic conductivity,reprocessability,and 3D-printability.Furthermore,an all-gel supercapacitor assembled from the regenerated hydrogel electrolyte and activated carbon electrode with CGs as binder demonstrates excellent interfacial compatibility.The assembled all-gel supercapacitor can maintain 98.7% of its original specific capacitance after 100 bending tests,and can operate in a wide temperature range spanning from-15 to 60°C.This work may provide a new access to the development of renewable materials for various applications in the fields of intelligent devices,wearable electronics and soft robotics.

Dynamic assembly and biocatalysis-selected gelation endow self-compartmentalized multienzyme superactivity

Cellular metabolism in multiple organelles utilizes compartmentalized multienzyme efficient catalysis to realize substance metabolism, energy conversion and immune defenses. The convenient and biomimetic design of artificial multienzymes has become an emerging research topic. Herein, we employ a facile enzyme-initiated radical polymerization to self-anchor multienzyme in cell-like hydrogels with mesoscale compartments. The dynamic assembly of glucose oxidase/cytochrome c(GOx/Cyt c) with methacrylate-modified hyaluronic acid can form nanoaggregates, where only the bound enzyme pairs with the adjacent position can catalyze the polymerization to compartmentalize multienzymes within hydrogel. Consequently, the cascade enzymes within hydrogel display 33.9 times higher activity compared to free enzymes, as well as excellent thermostability and multiple recyclability. The mechanism study indicates that the compartmental effect of the hydrogel and the anchoring effect of Cyt c synergistically enhance GOx/Cyt c activity. According to the density functional theory(DFT) calculation, Cyt c activity increment originates from its ligand changes of Fe(Ⅲ) porphyrin, which has a smaller energy barrier of the catalytic reaction.This study provides a promising strategy for autonomous colocalization of multienzyme in biocompatible hydrogels which can be potentially applied in cascade enzyme induced catalysis applications.

Spatiotemporally-regulated multienzymatic polymerization endows hydrogel continuous gradient and spontaneous actuation

There are several natural materials which have evolved functional gradients,ingeniously attaining maximal efficacy from limited components.Herein,we utilized the spatiotemporal distribution of initiator acetylacetone to regulate the multienzyme polymerization and fabricate a chitosan-polymer hydrogel.The temporal priority order of acetylacetone was higher than phenolmodified chitosan by density functional theory calculation.The acetylacetone within the gelatin could gradually diffuse spatially into the chitosan hydrogel to fabricate the composite hydrogel with gradient network structure.The gradient hydrogel possessed a transferring topography from the two-dimensional pattern.A continuously decreased modulus along with acetylacetone diffusion was confirmed by atomic force microscope-based force mapping experiment.The water-retaining ability of various regions was confirmed by low-field nuclear magnetic resonance(NMR)and thermogravimetric analysis(TG)analysis,which led to the spontaneous actuation of gradient hydrogel with maximum 1821°/h curling speed and 227°curling angle.Consequently,the promising gradient hydrogels could be applied as intelligent actuators and flexible robots.