Advanced electrospinning nanomaterials:From spinning fabrication techniques to electrochemical applications

Fuel cells,rechargeable metal–air batteries,metal-ion batteries,and supercapacitors have been regarded as prospective energy sources technologies to replace the fossil energy.Moreover,electrochemical sensors also have been successfully developed as promising platforms for detecting pollutants,drug analysis,and healthcare monitoring.Electrospinning is a scalable and suitable technique to design and fabricate diverse nanofibers and their nanocomposites for key components in electrochemical applications.Herein,a comprehensive review of electrospinning,from the technological innovations to the novel electrospun composite nanofibers,is provided.More importantly,the recent advances on the diverse components of electrochemical devices are highlighted,followed with the detailed discussion about the corresponding enhancement mechanism based on the electrospun nanomaterials.Finally,the currently faced challenges on the fabrication of electrospun nanomaterials are raised and a brief perspective for the future development of electrospun nanomaterials-based electrochemical applications is prospected.

APPLICATIONS AND MANUFACTURE OF THE MICROSCALE LONG-OPTICAL-PATH ELECTROCHEMICAL CELL WITH A PLUG-IN THIN-LAYER ELECTRODE

The construction and characteristics of a microscale long-optical-path electrochemi- cal cell with a plug-in thin-layer electrode are described.Using ferricyanide as the test species,the thermodynamic parameters of electron transfer processes are determined at car- bon,plantinum,and gold electrodes.

Electrochemical Determination of Rate Constants for Reactions of OH and its Application in the Evaluation of Anti-Oxidant Actions of Rheum

A single-sweep oscillopolarographic procedure is descrital which allows detethenahon of rateconstants for reachons of oH. For a wide range of compounds, the results fit well with rate constantspreviously obtained with other methods. Rate constants for reactions of six kinds of active compoundscontalned in rheum, a tradihonal Chinese herb, have been deteboned by this method. Rcationmechanism ha5 also been discussed.

Amorphous vanadium oxides for electrochemical energy storage

Vanadium oxides have attracted extensive interest as electrode materials for many electrochemical energy storage devices owing to the features of abundant reserves,low cost,and variable valence.Based on the in-depth understanding of the energy storage mechanisms and reasonable design strategies,the performances of vanadium oxides as electrodes for batteries have been significantly optimized.Compared to crystalline vanadium oxides,amorphous vanadium oxides(AVOs)show many unique properties,including large specific surface area,excellent electrochemical stability,lots of defects and active sites,fast ion kinetics,and high elasticity.This review gives a comprehensive overview of the recent progress on AVOs for different energy storage systems,such as alkali metal ion batteries,multivalent ion batteries,and supercapacitors with a special focus on the preparation strategies.The basic mechanisms for energy storage performance improvements of AVOs as compared to their crystalline counterparts are also introduced.Finally,challenges faced by AVOs are discussed and future development prospects are also proposed.This review aims to provide a comprehensive knowledge of AVOs and is expected to promote the development of high-performance electrodes for batteries.

Thermal Hydrolysis Synthesis and Characterization of Monoclinic Metahewettite CaV_6O_(16)·3H_2O

Monoclinic metabewettite CaV6O16·3H2O has been fabricated via thermal hydrolysis of calcium vanadate （Ca10V6O25）. High purity calcium vanadate precipitate, featuring colnmn structure with surface area of 8.61 m2/g, can be obtained by reacting sodium 0rthovanadate （Na3VO4） with calcium oxide at 90 ℃ for 2 h. By acidification of calcium vanadate in hot water at pH of 1.0-3.0, the monoclinic metabewettite crystals with uniform particle distribution, layered structure and nonporous structure can be fabricated. With the well crystallized layered structure, CaV6O16·3H2O may be a potential cathode material for secondary batteries as well as super capacitor materials.

V_(2)CT_(x) MXene and its derivatives:synthesis and recent progress in electrochemical energy storage applications

With the continuous development of two-dimensional (2D) transition metal carbides and nitrides(collectively referred to as MXene).Nowadays,more than 70 MXene materials have been discovered,and the number is still increasing.Among them,the V_(2)CT_(x) MXene has attracted considerable attentions due to its outstanding physical and chemical properties.In this review,we mainly discussed the emerging V_(2)CT_(x) MXene and its derivative systems in various energy storage devices.Firstly,an introduction of the V-based MXene and its derivatives along with their synthetic methodologies is provided,then we summarize their applications in specific energy storage devices,such as metal (Li,Na,K,Mg,Zn and Al) ion batteries,lithium-sulfur batteries,supercapacitors and metal-ion capacitors.Finally,the main challenges and future perspectives existing in V-based MXene and its derivatives are reasonably put forward.