Wearable and stretchable conductive polymer composites for strain sensors:How to design a superior one?

Wearable and stretchable strain sensors have potential values in the fields of human motion and health monitoring,flexible electronics,and soft robotic skin.The wearable and stretchable strain sensors can be directly attached to human skin,providing visualized detection for human motions and personal healthcare.Conductive polymer composites(CPC)composed of conductive fillers and flexible polymers have the advantages of high stretchability,good flexibility,superior durability,which can be used to prepare flexible strain sensors with large working strain and outstanding sensitivity.This review has put forward a comprehensive summary on the fabrication methods,advanced mechanisms and strain sensing abilities of CPC strain sensors reported in recent years,especially the sensors with superior performance.Finally,the structural design,bionic function,integration technology and further application of CPC strain sensors are prospected.

Sodium-Coordinated Polymeric Phthalocyanines as Stable High-Capacity Organic Anodes for Sodium-Ion Batteries

Sodium-ion batteries(SIBs)have attracted considerable interest as an alternative to lithium-ion batteries owing to their similar electrochemical performance and superior long-term cycle stability.Organic materials are regarded as promising anode materials for constructing SIBs with high capacity and good retention.However,utilization of organic materials is rather limited by their low energy density and poor stability at high current densities.To overcome these limitations,we utilized a novel polymeric disodium phthalocyanines(pNaPc)as SIB anodes to provide stable coordination sites for Na ions as well as to enhance the stability at high current density.By varying the linker type during a one-pot cyclization and polymerization process,two pNaPc anodes with O-(O-pNaPc)and S-linkers(S-pNaPc)were prepared,and their structural and electrochemical properties were investigated.The O-pNaPc binds Na ions with a lower binding energy compared with S-pNaPc,which leads to more facile Na-ion coordination/dissociation when engaged as SIB anode.The use of O-pNaPc significantly improves the redox kinetics and cycle stability and allows the fabrication of a full cell against Na_(3)V_(2)(PO_(4))_(2)F_(3)/C cathode,which demonstrates its practical application with high energy density(288 Wh kg^(-1))and high power density(149 W kg^(-1)).

Chemical modification of ordered/disordered carbon nanostructures for metal hosts and electrocatalysts of lithium-air batteries

Although lithium-air batteries(LABs)are considered the promising alternative of existing lithium–ion batteries owing to their high energy density of 11680 W h kg^(-1),their practical applications are limited by the technical issues,such as unstable solid electrolyte interface and dendrite formation from metal anode and insufficient bifunctional activities and durability from cathode catalyst.In order to resolve these bottlenecks,carbon nanostructures have been investigated owing to their high surface area,excellent electrical conductivity,electrochemical stability,and various modification chemistries.Herein,we comprehensively review a recent progress on the design of carbon nanostructures for their applications into metal hosts,protection layers,and bifunctional electrocatalysts of LABs.The correlation between the crystalline,electronic,porous,and chemical structures and the electrochemical properties of carbon nanomaterials are discussed depending on their classification and characteristics.Various chemical modifications,such as morphological control,hierarchical architecturing,heteroatom incorporation,and the formation of composites,for the improved electrochemical performances of anode and cathode will be also addressed.Furthermore,we deal with the perspectives for the ongoing obstruction and future guidance.