Dual-aligned porous electrodes for enhanced hydrogen evolution in alkaline water electrolysis

The efficiency of water electrolysis is significantly affected by the bubbles on the surface and inside the electrode.To enhance the gas-liquid transfer within the porous electrodes,we developed an innovative design termed dual-aligned porous electrode(D-APE),achieved by integrating magnetic alignment with freeze casting techniques.This paper investigates the hydrogen evolution performance of porous electrodes prepared using four different methods:evaporation,magnetic-aligned evaporation,freeze casting,and dual-aligned methods.The findings demonstrate that the magnetic-aligned process effectively alters the electrode structure,resulting in improved hydrogen evolution performance.Notably,among all the examined electrodes,the D-APE exhibits the highest hydrogen evolution performance,with further enhancements observed with prolonged the time of magnetic alignment.Furthermore,a comparison is made between electrodes prepared using the freeze casting method and the dual-aligned method at various thickness.The results show that the thinner D-APE exhibits excellent hydrogen evolution performance at high current density.Moreover,the D-APE demonstrates significantly improved material utilization rates compared to the conventional freeze casting method,offering promising prospects for enhancing the efficiency of water electrolysis.

Ultra-sensitive and wide applicable strain sensor enabled by carbon nanofibers with dual alignment for human machine interfaces

Flexible strain sensors with high sensitivity,wide detection range,and low detection limit have continuously attracted great interest due to their tremendous application potential in areas such as health/medical-care,human-machine interface,as well as safety and security.While both of a high sensitivity and a wide working range are desired key parameters for a strain sensor,they are usually contrary to each other to be achieved on the same sensor due to the tightly structure dependence of both of them.Here,a flexible strain sensor with both high sensitivity and wide strain detection range is prepared based on the design of an integrated membrane containing both of parallel aligned and randomly aligned carbon nanofibers(CNFs).The parallel aligned CNF membrane(p-CNF)exhibits a low strain detection limit and high sensitivity,while the random aligned CNF membrane(r-CNF)exhibits a large strain detection range.Taking the advantages of both p-CNF and r-CNF,the strain sensor with stacked p-CNF and r-CNF(p/r-CNF)exhibits both high sensitivity and wide working range.Its gauge factor(GF)is 1,272 for strains under 0.5%and 2,266 for strain from 70%to 100%.At the same time,it can work in a wide strain range of 0.005%to 100%,fulfilling the requirements for accurately detecting full-range human motions.We demonstrated its applications in the recognition of facial expressions and joint movements.Furtherly,we constructed an intelligent lip-language recognition system,which can accurately track phonetic symbols and may help people with language disabilities,proving the potential of this strain sensor in health management and medical assistance.Besides,we foresee that the dual-alignment structure design of the p/r-CNF strain sensor may also be applied in the design of other high performance sensors.