A Healable and Mechanically Enhanced Composite with Segregated Conductive Network Structure for High‑Efficient Electromagnetic Interference Shielding

It is still challenging for conductive polymer composite-based electromagnetic interference(EMI)shielding materials to achieve long-term stability while maintaining high EMI shielding effectiveness(EMI SE),especially undergoing external mechanical stimuli,such as scratches or large deformations.Herein,an electrostatic assembly strategy is adopted to design a healable and segregated carbon nanotube(CNT)/graphene oxide(GO)/polyurethane(PU)composite with excellent and reliable EMI SE,even bearing complex mechanical condition.The negatively charged CNT/GO hybrid is facilely adsorbed on the surface of positively charged PU microsphere to motivate formation of segregated conductive networks in CNT/GO/PU composite,establishing a high EMI SE of 52.7 dB at only 10 wt%CNT/GO loading.The Diels–Alder bonds in PU microsphere endow the CNT/GO/PU composite suffering three cutting/healing cycles with EMI SE retention up to 90%.Additionally,the electrostatic attraction between CNT/GO hybrid and PU microsphere helps to strong interfacial bonding in the composite,resulting in high tensile strength of 43.1 MPa and elongation at break of 626%.The healing efficiency of elongation at break achieves 95%when the composite endured three cutting/healing cycles.This work demonstrates a novel strategy for developing segregated EMI shielding composite with healable features and excellent mechanical performance and shows great potential in the durable and high precision electrical instruments.

Stretchable, self‐healable, and breathable biomimetic iontronics with superior humidity‐sensing performance for wireless respiration monitoring

Stretchable,self‐healing,and breathable skin‐biomimetic‐sensing iontronics play an important role in human physiological signal monitoring and human–computer interaction.However,previous studies have focused on the mimicking of skin tactile sensing(pressure,strain,and temperature),and the development of more functionalities is necessary.To this end,a superior humidity‐sensitive ionic skin is developed based on a self‐healing,stretchable,breathable,and biocompatible polyvinyl alcohol–cellulose nanofibers organohydrogel film,showing a pronounced thickness‐dependent humidity‐sensing performance.The as‐prepared 62.47‐μm‐thick organohydrogel film exhibits a high response(25,000%)to 98%RH,excellent repeatability,and long‐term stability(120 days).Moreover,this ionic skin has excellent resistance to large mechanical deformation and damage,and the worn‐out material can still retain its humidity‐sensing capabilities after self‐repair.Humidity‐sensing mechanism studies show that the induced response is mainly related to the increase of proton mobility and interfacial charge transport efficiency after water adsorption.The superior humidity responsiveness is attributed to the reduced thickness and the increased specific surface area of the organohydrogel film,allowing real‐time recording of physiological signals.Notably,by combining with a self‐designed printed circuit board,a continuous and wireless respiration monitoring system is developed,presenting its great potential in wearable and biomedical electronics.

Design of multifunctional polymeric binders in silicon anodes for lithium‐ion batteries

Silicon(Si)is a promising anode material for lithium‐ion batteries(LIBs)owing to its tremendously high theoretical storage capacity(4200 mAh g−1),which has the potential to elevate the energy of LIBs.However,Si anodes exhibit severe volume change during lithiation/delithiation processes,resulting in anode pulverization and delamination with detrimental growth of solid electrolyte interface layers.As a result,the cycling stability of Si anodes is insufficient for commercialization in LIBs.Polymeric binders can play critical roles in Si anodes by affecting their cycling stability,although they occupy a small portion of the electrodes.This review introduces crucial factors influencing polymeric binders'properties and the electrochemical performance of Si anodes.In particular,we emphasize the structure–property relationships of binders in the context of molecular design strategy,functional groups,types of interactions,and functionalities of binders.Furthermore,binders with additional functionalities,such as electrical conductivity and self‐healability,are extensively discussed,with an emphasis on the binder design principle.

Repairable,Recyclable,and Regenerable Macrocycle Organic Polymer

Covalent/metal organic frameworks are highly attractive due to their tunable structure and properties,and broad applications in multiple fields.However,they still suffer from numbers of drawbacks including low solubility,harsh synthesis and fabrication,and low mechanical flexibility.Herein,we report a new organic framework consisting of macrocycles and organic frames in its periodic structure,and denote it as macrocycle organic polymer(MOP).The size-tunable macrocycles containing peripheral furan units are synthesized by anionic ring-opening polymerization,which undergo a reversible Diels-Alde reaction with bismaleimide to generate/degrade MOPs at given temperatures.Relying on above features,MOPs exhibit excellent flexibility,healable ability and recycle ability.Interestingly,owing to the“living”nature of anionic ring-opening polymerization,MOPs can self-grow into bigger sizes in the presence of monomer and catalysis,analogs to the living creatures.Moreover,their high porosity and rich thioether structure enable them as good metal ion absorbers and promising applications in wearable electronics.