In this critical review, metal oxides-based materials for electrochemical supercapacitor (ES) electrodes are reviewed in detail together with a brief review of carbon materials and conducting polymers. Their advantages, disadvantages, and performance in ES electrodes are discussed through extensive analysis of the literature, and new trends in material development are also reviewed. Two important future research directions are indicated and summarized, based on results published in the literature: the development of composite and nanostructured ES materials to overcome the major challenge posed by the low energy density of ES (476 references).

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A review of electrode materials for electrochemical supercapacitors

Li-ion battery materials: present and future

Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.

/pdf/carbon-nanotubes-present-and-future-commercial-applications-1nhq3xy4hh.pdf

Carbon Nanotubes: Present and Future Commercial Applications

Electrochemical energy storage technology is based on devices capable of exhibiting high energy density (batteries) or high power density (electrochemical capacitors). There is a growing need, for current and near-future applications, where both high energy and high power densities are required in the same material. Pseudocapacitance, a faradaic process involving surface or near surface redox reactions, offers a means of achieving high energy density at high charge–discharge rates. Here, we focus on the pseudocapacitive properties of transition metal oxides. First, we introduce pseudocapacitance and describe its electrochemical features. Then, we review the most relevant pseudocapacitive materials in aqueous and non-aqueous electrolytes. The major challenges for pseudocapacitive materials along with a future outlook are detailed at the end.

https://hal.archives-ouvertes.fr/hal-01171774/document

Pseudocapacitive oxide materials for high-rate electrochemical energy storage

Electrospinning is a highly versatile method to process solutions or melts, mainly of polymers, into continuous fibers with diameters ranging from a few micrometers to a few nanometers. This technique is applicable to virtually every soluble or fusible polymer. The polymers can be chemically modified and can also be tailored with additives ranging from simple carbon-black particles to complex species such as enzymes, viruses, and bacteria. Electrospinning appears to be straightforward, but is a rather intricate process that depends on a multitude of molecular, process, and technical parameters. The method provides access to entirely new materials, which may have complex chemical structures. Electrospinning is not only a focus of intense academic investigation; the technique is already being applied in many technological areas.

Electrospinning: A Fascinating Method for the Preparation of Ultrathin Fibers

A nanofluid electrolyte of single walled carbon nanotubes and ionic liquids can enhance the energy density, power density and cycling stability of nanotube electrodes with a surface area of 600 m2 g−1 at 5 V, by decreasing internal resistance from the bulk phase of ILs to the electrolyte/electrode interface.

Enhancing 5 V capacitor performance by adding single walled carbon nanotubes into an ionic liquid electrolyte

Hydrocarbons such as methane, ethylene, and CO with high purity (> 99.9%) have been widely used to synthesize single-walled carbon nanotubes (SWCNTs). Here, liquefied petroleum gas (LPG) was used to synthesize SWCNTs by catalytic chemical vapor deposition. The LPG converted into CNTs and other stable hydrocarbons. The BET specific surface area of SWCNT was about 583 m2/g. The as-grown SWCNT showed good graphitization. The graphitization can be further modulated by the growth temperature. Certain amount of sulfur in LPG was a promoter for SWCNT growth. Compared SWCNTs obtained from methane, more semiconductive SWCNTs were synthesized from LPG as carbon source. The LPG is in low price, thus, a methodology to lower the production cost of SWCNTs with hydrocarbon mixtures is realized.

Synthesis of single-walled carbon nanotubes from liquefied petroleum gas

Carbon nanotubes (CNTs) are promising building blocks for nanodevices owing to their superior electrical, thermal and mechanical properties. One of the key issues for their study and application is the efficient location, transfer and manipulation of individual CNTs. In this contribution, we show that the manipulation of individual suspended CNTs has been carried out on the macroscale under low magnification, using inorganic nanoparticles (NPs) as indicators. Individual ultralong CNTs can be stretched, cut, and transferred to other substrates for further characterization. Complicated CNT structures were fabricated under optical microscopes. The inorganic NPs also facilitate the manipulation and characterization of individual CNTs under a scanning electron microscope with low magnification. Additionally, the irregular NPs deposited on suspended CNTs can also make the outer shell of the suspended CNTs display torsion or rotation around the inner shells when placed in a flow of gas, making the fabrication of CNT–NP-hybrid-based nanodevices feasible. Our results demonstrate the extraordinary capability of this manipulation technique for individual CNTs, enabled by decoration with inorganic NPs.

Facile manipulation of individual carbon nanotubes assisted by inorganic nanoparticles

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adfm.201870360

Supercapacitors: Cross‐Coupled Macro‐Mesoporous Carbon Network toward Record High Energy‐Power Density Supercapacitor at 4 V (Adv. Funct. Mater. 51/2018)

The present invention relates to an ultralong oriented carbon nano tube wire/film and its preparation method. The described carbon nano tube wire/film is made up by using mutually-winded and connected tube bundle end portions of several bundles of carbon nano tubes, their orientations are basically identical, the macrodiameter is above micrometer grade, length is above centrimeter grade, the macrothickness of carbon nano tube film is above several tens nanometers, its width is above several tens micrometers and its length is above centrimeter grade. Its preparation method includes the following steps: utilizing floatation process to make the carbon nano tube array be grown out from base surface, then using tension tool to draw carbon nano tube wire or film from one end of carbon nano tube array, utilizing continuous tension to make the tube bundle of carbon nano tube be formed into oriented carbon nano tube wire/film along the tension direction.

Weizhong Qian

Papers

Enhancing 5 V capacitor performance by adding single walled carbon nanotubes into an ionic liquid electrolyte

Synthesis of single-walled carbon nanotubes from liquefied petroleum gas

Facile manipulation of individual carbon nanotubes assisted by inorganic nanoparticles

Supercapacitors: Cross‐Coupled Macro‐Mesoporous Carbon Network toward Record High Energy‐Power Density Supercapacitor at 4 V (Adv. Funct. Mater. 51/2018)

Ultralong orientational carbon nano-tube filament/film and its preparation method