Hierarchical assembly of manganese dioxide nanosheets on one-dimensional titanium nitride nanofibers for high-performance supercapacitors

Blow-Spun Nanofibrous Membrane for Simultaneous Treatment of Emulsified Oil/Water Mixtures, Dyes, and Bacteria

Membrane separation is of great significance due to its unique performance in treating wastewater. However, the simultaneous treatment of oily emulsions and other complex pollutants in water remains challenging. Herein, we have proposed a simple strategy to prepare a multifunctional titanium dioxide/silver nanoparticles/polyacrylonitrile (TiO₂/AgNPs/PAN) nanofibrous membrane. The experimental results showed that the combination of the hierarchical structure composed of PAN nanofibers and Ag/TiO₂ nanoprotrusions contributed to the superhydrophilicity and superoleophobicity (UOCA = 153.3 ± 2.0°). Further, the nanofibrous membrane exhibited a rapid gravity-driven permeate flux (>1829.37 ± 83.51 L m^-2 h^-1) and an ultrahigh separation efficiency (>99.9%) for the surfactant-stabilized oil/water emulsions. Moreover, due to the synergistic effect between the PAN fibers and TiO₂/Ag heterojunction, Rhodamine B dye in water can be removed quickly and efficiently (up to 97.67% in 90 min). More importantly, the obtained nanofibrous membrane exhibited ultrahigh stability in different harsh environments. The design of superoleophobic nanofiber membrane with a high separation efficiency and high photocatalytic activity has great potential for practical applications in the purification of oily wastewater.

Transition metal nitrides for electrochemical energy applications

This review comprehensively summarizes the progress on the structural and electronic modulation of transition metal nitrides for electrochemical energy applications.

Nitrogen and Phosphorus Co-doped Porous Carbon for High-Performance Supercapacitors

As one of the most promising fast energy storage devices, supercapacitor has been attracting intense attention for many emerging applications. However, how to enhance the electrochemical performance of electrode materials is still the main issue among various researches. In this paper, hierarchical porous carbons derived from Eleocharis dulcis has been prepared by chemical activation process with the aid of KOH at elevated temperature. Results show that the N, P co-doped porous carbon exhibits excellent electrochemical performance, it owns a specific capacitance of 340.2 F/g at 1 A/g, and obtains outstanding cycling stability of 96.9% of capacitance retention at 10 A/g after 5,000 cycles in a three-electrode system. Moreover, in the two-electrode system, the product still maintains a high specific capacitance of 227.2 F/g at 1 A/g, and achieves good electrochemical cycle stability (94.2% of capacitance retention at 10 A/g after 10,000 cycles); besides, its power/energy density are 3694.084 and 26.289 Wh/kg, respectively. Therefore, the combination of facile synthesis strategy and excellent electrochemical performance makes Eleocharis dulcis-based porous carbon as a promising electrode material for supercapacitor.

Conductive Electrospun Nanofiber Mats

Conductive nanofiber mats can be used in a broad variety of applications, such as electromagnetic shielding, sensors, multifunctional textile surfaces, organic photovoltaics, or biomedicine. While nanofibers or nanofiber from pure or blended polymers can in many cases unambiguously be prepared by electrospinning, creating conductive nanofibers is often more challenging. Integration of conductive nano-fillers often needs a calcination step to evaporate the non-conductive polymer matrix which is necessary for the electrospinning process, while conductive polymers have often relatively low molecular weights and are hard to dissolve in common solvents, both factors impeding spinning them solely and making a spinning agent necessary. On the other hand, conductive coatings may disturb the desired porous structure and possibly cause problems with biocompatibility or other necessary properties of the original nanofiber mats. Here we give an overview of the most recent developments in the growing field of conductive electrospun nanofiber mats, based on electrospinning blends of spinning agents with conductive polymers or nanoparticles, alternatively applying conductive coatings, and the possible applications of such conductive electrospun nanofiber mats.

Hollow Co3O4@MnO2 Cubic Derived From ZIF-67@Mn-ZIF as Electrode Materials for Supercapacitors

Hollow Co₃O₄@MnO₂ cubic nanomaterials are synthesized by ZIF-67@Mn-ZIF sacrificial precursor through a facile thermal treatment. As a kind of supercapacitor electrode material, it demonstrates high performances, such as specific capacitance of 413 F g⁻¹ at the current density of 0.5 A g⁻¹; as the current densities raised from 0.5 to 10 A g⁻¹ (20 times increasing), there is still ~41% retention of its initial capacitance. These satisfactory electrochemical properties should be put down to the hollow and porous structure and the relative higher BET surface area, which supplies more reactive sites for charge and discharge processes.

Three-Dimensional Graphene-Based Composite Hydrogel Materials for Flexible Supercapacitor Electrodes

Three-dimensional (3D) graphene-based hydrogels have attracted great interest for applying in supercapcacitors electrodes, owing to their intriguing properties that combine the structural interconnectivities and the outstanding properties of graphene. However, the pristine graphene hydrogel can not satisfy the high-performance demands, especial in high specific capacitance. Consequently, novel graphene-based composite hydrogels with increased electrochemical properties have been developed. In this mini review, a brief summary of recent progress in the research of the three-dimensional graphene-based composite hydrogel for flexible supercapacitors electrodes materials is presented. The latest progress in the graphene-based composite hydrogel consisting of graphene/metal, graphene/polymer, and atoms doped graphene is discussed. Furthermore, future perspectives and challenges in graphene-based composite hydrogel for supercapacitor electrodes are also expressed.

Liquid Phase Exfoliated Hexagonal Boron Nitride/Graphene Heterostructure Based Electrode Toward Asymmetric Supercapacitor Application

In this paper, owing to the electrostatic interaction between graphene and h-BN, a facile liquid phase exfoliation method was carried out to fabricate h-BN/graphene based van der Waals heterostructure nanocomposites without additional chemical cross-linkers. The physicochemical properties of as-prepared composites were characterized by several electron microscopic and spectroscopic measurements. The h-BN/graphene heterostructure composites were employed to use as the anodes of asymmetric supercapacitor, and exhibited exceptional capacitive performance due to their synergistic effects. It is expected that the as-prepared h-BN/graphene materials can boost scalable heterostructure electrodes in supercapacitors, and our liquid phase exfoliation method can be used for the construction of the other energy storage and electronics.