Electrospinning is a versatile and viable technique for generating ultrathin fibers. Remarkable progress has been made with regard to the development of electrospinning methods and engineering of electrospun nanofibers to suit or enable various applications. We aim to provide a comprehensive overview of electrospinning, including the principle, methods, materials, and applications. We begin with a brief introduction to the early history of electrospinning, followed by discussion of its principle and typical apparatus. We then discuss its renaissance over the past two decades as a powerful technology for the production of nanofibers with diversified compositions, structures, and properties. Afterward, we discuss the applications of electrospun nanofibers, including their use as "smart" mats, filtration membranes, catalytic supports, energy harvesting/conversion/storage components, and photonic and electronic devices, as well as biomedical scaffolds. We highlight the most relevant and recent advances related to the applications of electrospun nanofibers by focusing on the most representative examples. We also offer perspectives on the challenges, opportunities, and new directions for future development. At the end, we discuss approaches to the scale-up production of electrospun nanofibers and briefly discuss various types of commercial products based on electrospun nanofibers that have found widespread use in our everyday life.

Electrospinning and Electrospun Nanofibers: Methods, Materials, and Applications

Electrical energy storage (EES) is one of the most critical areas of technological research around the world. Storing and efficiently using electricity generated by intermittent sources and the transition of our transportation fleet to electric drive depend fundamentally on the development of EES systems with high energy and power densities. Supercapacitors are promising devices for highly efficient energy storage and power management, yet they still suffer from moderate energy densities compared to batteries. To establish a detailed understanding of the science and technology of carbon/carbon supercapacitors, this review discusses the basic principles of the electrical double-layer (EDL), especially regarding the correlation between ion size/ion solvation and the pore size of porous carbon electrodes. We summarize the key aspects of various carbon materials synthesized for use in supercapacitors. With the objective of improving the energy density, the last two sections are dedicated to strategies to increase the capacitance by either introducing pseudocapacitive materials or by using novel electrolytes that allow to increasing the cell voltage. In particular, advances in ionic liquids, but also in the field of organic electrolytes, are discussed and electrode mass balancing is expanded because of its importance to create higher performance asymmetric electrochemical capacitors.

Carbons and Electrolytes for Advanced Supercapacitors

This paper presents a review of the research progress in the carbon–metal oxide composites for supercapacitor electrodes. In the past decade, various carbon–metal oxide composite electrodes have been developed by integrating metal oxides into different carbon nanostructures including zero-dimensional carbon nanoparticles, one-dimensional nanostructures (carbon nanotubes and carbon nanofibers), two-dimensional nanosheets (graphene and reduced graphene oxides) as well as three-dimensional porous carbon nano-architectures. This paper has described the constituent, the structure and the properties of the carbon–metal oxide composites. An emphasis is placed on the synergistic effects of the composite on the performance of supercapacitors in terms of specific capacitance, energy density, power density, rate capability and cyclic stability. This paper has also discussed the physico-chemical processes such as charge transport, ion diffusion and redox reactions involved in supercapacitors.

Nanostructured carbon–metal oxide composite electrodes for supercapacitors: a review

Leu-M

Poly(ethylene oxide) (PEO) based materials are widely considered as promising candidates of polymer hosts in solid-state electrolytes for high energy density secondary lithium batteries. They have several specific advantages such as high safety, easy fabrication, low cost, high energy density, good electrochemical stability, and excellent compatibility with lithium salts. However, the typical linear PEO does not meet the production requirement because of its insufficient ionic conductivity due to the high crystallinity of the ethylene oxide (EO) chains, which can restrain the ionic transition due to the stiff structure especially at low temperature. Scientists have explored different approaches to reduce the crystallinity and hence to improve the ionic conductivity of PEO-based electrolytes, including blending, modifying and making PEO derivatives. This review is focused on surveying the recent developments and issues concerning PEO-based electrolytes for lithium-ion batteries.

Poly(ethylene oxide)-based electrolytes for lithium-ion batteries

Microbundles of carbon nanostructures as binder free highly conductive matrix for LiFePO4 battery cathode

Electrochemical performance of nonflammable polymeric gel electrolyte containing triethylphosphate

Nano zeolite-Y ultrafiltration (UF) membrane, with mean pore diameter of 28 nm was fabricated using a simple isostatic pressing technique. Zeolite-Y has preferential water pathways and a unique 3-D microporous structure. The zeolite-Y used in this study has an Al to Si (Al/Si) ratio of 0.07 which renders the membrane superhydrophilic with complete wetting of water in air. Whereas, when it is underwater, the membrane is superoleophobic with a contact angle of 156°. This study compared membranes with two different zeolite particle sizes, above and below 100 nm for their membrane morphology, and wetting properties, directly affecting the separation of oil-in-water separation. The membrane separation capabilities were tested for 600 mg/L of xylene, motor oil and crude oil mixture in water. There are limited studies on treating oil/water mixtures having nanoemulsions with stand-alone zeolite membranes, and thus this study provides a deeper insight on utilizing such a ceramic material for improved separation processes. A flux of 45−70 L/m2.h was obtained for the nano-zeolite membrane, depending upon the type of oil, with the motor oil giving the lowest flux due to its heavy components. The nano-zeolite membranes produced ∼ 20 % higher flux than the micro-zeolite membrane at a membrane pressure of 70 kPa. A higher flux was attributed to the higher membrane porosity and favored nano-channel pathways along the zeolite pores for the water molecules. In addition, oil rejections as high as 99.8 % with oil content as low as 1.57 ± 0.2 mg/L were obtained. Thus, the membrane was found to be very effective in nanoemulsion oil-water separation owing to its exceptional structural properties and superoleophobicity of oil under water.

Boor Singh Lalia

Papers

Microbundles of carbon nanostructures as binder free highly conductive matrix for LiFePO4 battery cathode

Electrochemical performance of nonflammable polymeric gel electrolyte containing triethylphosphate

Superhydrophilic and underwater superoleophobic nano zeolite membranes for efficient oil-in-water nanoemulsion separation

Hierarchical underwater oleophobic electro-ceramic/carbon nanostructure membranes for highly efficient oil-in-water separation

Effects of Lewis-acid polymer on the electrochemical properties of alkylphosphate-based non-flammable gel electrolyte