Search

The growing demand for flexible, biocompatible, and environmentally friendly power sources for wearable devices has led to an increased interest in alternative technologies. Among them, reverse electrodialysis (RED) stands out as a promising renewable energy technology, harnessing salinity gradients between seawater and river water to generate electricity. Although RED has a high potential as a power source, conventional RED designs face challenges in increasing power density, stability, and versatility particularly when it is miniaturised for portable applications. Owing to its serially stacked structure, RED can only provide very small currents to the external load, as the internal resistance increases proportionally with the number of membranes. Additionally, RED may produce an unstable voltage output because the current cannot bypass blockages or broken circuits through alternative pathways. In this study, we address these challenges by introducing a novel parallel structure, four-way diffusion compact RED (cRED), which enhances the stability while increasing the power density by reducing the total volume. Theoretical properties of various forms of parallel-connected series RED (pRED) and cRED were investigated. cRED can achieve up to twice higher volumetric power density compared to pRED due to its compact structure. Furthermore, cRED exhibits superior voltage stability and current amplification to those of conventional series designs. The advancement enables the utilisation of the miniaturised RED as a power source, preventing waste from conventional batteries where only a small power is required, offering a compact, versatile, and sustainable alternative for renewable energy generation, promising environmentally friendly energy solutions. [ABSTRACT FROM AUTHOR]

Room temperature ionic liquids (RT-ILs) are promising electrolytes for electrocatalysis. Understanding the effects of the electrode–electrolyte interface structure on electrocatalysis in RT-ILs is important. Ultrafast mass transport of redox species in N-methyl-N-ethyl-pyrrolidinium polybromide (MEPBr2n+1) enabled evaluation of the reorganization energy (λ), which reflects the solvation structure in the inner Helmholtz plane (IHP). λ was achieved by fitting the electron transfer rate-limited voltammogram at a Pt ultramicroelectrode (UME) to the Marcus–Hush–Chidsey model for heterogeneous electron transfer kinetics. However, it is time-consuming or even impossible to prepare electrode materials, including alloys of numerous compositions in the form of UME, for each experiment. Herein, we report a method to evaluate the λ of MEPBr2n+1 by scanning electrochemical cell microscopy (SECCM), which allows high throughput electrochemical measurements using a single electrode with high spatial resolution. Fast mass transport in the nanosized SECCM tip is critical for achieving heterogeneous electron transfer-limited voltammograms. Furthermore, investigating λ on a high-entropy alloy materials library composed of Pt, Pd, Ru, Ir, and Ag suggests a negative correlation between λ and the work function. Given that the potential of zero charge correlates with the work function of electrodes, this can be attributed to the surface-charge sensitive ionic structure in the IHP of MEPBr2n+1, modulating the solvation energy of the redox-active species in the IHP. [ABSTRACT FROM AUTHOR]

High‐entropy alloys (HEAs), especially in the form of compositional complex solid solutions (CCSS), have gained attention in the field of electrocatalysis. However, exploring their vast composition space concerning their electrocatalytic properties imposes significant challenges. Scanning electrochemical cell microscopy (SECCM) offers high‐speed electrochemical analysis on surface areas with a lateral resolution down to tens of nm. However, high‐precision piezo positioners often used for the motion of the tip limit the area of SECCM scans to the motion range of the piezo positioners which is typically a few tens of microns. To bridge this experimental gap, the study proposes a long‐range SECCM system with a rapid gas‐exchange environmental cell for high‐throughput electrochemical characterization of 100 mm diameter HEA thin‐film material libraries (ML) obtained by combinatorial co‐sputtering. Due to the gas–liquid interface at the positioned SECCM droplet on the sample, high‐throughput evaluation under industrial current density conditions becomes feasible. This allows the direct correlation between electrocatalytic activity and material composition with high statistical reliability. The multidimensional data obtained accelerates materials discovery, development, and optimization. [ABSTRACT FROM AUTHOR]