Enhanced Electrochemical Properties of Na0.67MnO2 Cathode for Na-Ion Batteries Prepared with Novel Tetrabutylammonium Alginate Binder

Both the binder and solid–electrolyte interface play an important role in improving the cycling stability of electrodes for Na-ion batteries. In this study, a novel tetrabutylammonium (TBA) alginate binder is used to prepare a Na0.67MnO2 electrode for sodium-ion batteries with improved electrochemical performance. The ageing of the electrodes is characterized. TBA alginate-based electrodes are compared to polyvinylidene fluoride- (PVDF) and Na alginate-based electrodes and show favorable electrochemical performance, with gravimetric capacity values of up to 164 mAh/g, which is 6% higher than measured for the electrode prepared with PVDF binder. TBA alginate-based electrodes also display good rate capability and improved cyclability. The solid–electrolyte interface of TBA alginate-based electrodes is similar to that of PVDF-based electrodes. As the only salt of alginic acid soluble in non-aqueous solvents, TBA alginate emerges as a good alternative to PVDF binder in battery applications where the water-based processing of electrode slurries is not feasible, such as the demonstrated case with Na0.67MnO2.

Simultaneous Electrospinning and Electrospraying for the Preparation of a Precursor Membrane Containing Hydrothermally Generated Biochar Particles to Produce the Value-Added Product of Carbon Nanofibrous Felt

Biochar is a byproduct generated from the hydrothermal liquefaction of biomass, such as corn stover, in an anaerobic environment. This work aims to convert biochar into a value-added product of carbon nanofibrous felt. First, the biochar-containing precursor membrane was prepared from simultaneous electrospinning and electrospraying. After thermal stabilization in air and carbonization in argon, the obtained precursor membrane was converted into a mechanically flexible and robust carbon nanofibrous felt. Electrochemical results revealed that the biochar-derived carbon nanofibrous felt might be a good candidate as a supercapacitor electrode with a good rate capability and high kinetic performance.

Hexagonal petal-like cobalt oxide nanowire arrays encapsulated by MOF-derived Co/N-codoped carbon for boosting electrochemical capacitor behaviour

A novel core–shell hetero-structured electrode (NF@CoO@Co/N–C) is designed and synthesized via a “anchor-etch-calcine” process for boosting electrochemical capacitor behaviour. The unique structure endows NF@CoO@Co/N–C with ultrahigh areal capacitances and good rate capability.

Hierarchical Porous RGO/PEDOT/PANI Hybrid for Planar/Linear Supercapacitor with Outstanding Flexibility and Stability

Many hybrid electrodes for supercapacitors (SCs) are a reckless combination without proper structural design that keeps them from fulfilling their potential. Herein, we design a reduced graphene oxide/poly(3,4-ethylenedioxythiophene)/polyaniline (RGO/PEDOT/PANI) hybrid with hierarchical and porous structure for high-performance SCs, where components fully harness their advantages, forming an interconnected and conductive framework with substantial reactive sites.Thus, this hybrid achieves a high capacitance of 535 F g−1 along with good rate capability and cyclability. The planar SC based on this hybrid deliver an energy density of 26.89 Wh kg−1 at a power density of 800 W kg−1. The linear SC developed via modifying a cotton yarn with the hybrid exhibits good flexibility and structural stability, which operates normally after arbitrary deformations. This work provides a beneficial reference for developing SCs.

One-Step Synthesis of Self-Supported Ni3S2/NiS Composite Film on Ni Foam by Electrodeposition for High-Performance Supercapacitors

Herein, a facile one-step electrodeposition route was presented for preparing Ni3S2/NiS composite film on Ni foam substrate (denoted as NiSx/NF). The NiSx granular film is composed of mangy interconnected ultra-thin NiSx nanoflakes with porous structures. When applied as electrodes for supercapacitors, the ultra-thin nanoflakes can provide more active sites for redox reaction, and the interconnected porous structure has an advantage for electrolyte ions to penetrate into the inner space of active materials quickly. As expected, the obtained NiSx/NF sample exhibited high gravimetric capacitance of 1649.8 F·g−1 and areal capacitance of 2.63 F·cm−2. Furthermore, a gravimetric capacitance of 1120.1 F·g−1 can be maintained at a high current density of 20 mA·cm−2, suggesting a good rate capability. The influence of the different molar ratios of electrodeposition electrolyte (NiNO3 and thiourea) on the morphology and electrochemical properties of NiSx/NF sample was investigated to provide an optimum route for one-step electrodeposition of Ni3S2/NiS composite film. The outstanding performance indicated the Ni3S2/NiS composite film on Ni foam has great potential as an electrode material for supercapacitors.

Facile Synthesis of Antimony Tungstate Nanosheets as Anodes for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have been widely used in the fields of smart phones, electric vehicles, and smart grids. With its opened Aurivillius structure, tungstate antimony oxide (Sb2WO6, SWO), constituted of {Sb2O2}2n+ and {WO4}2n−, is rarely investigated as an anode for lithium-ion batteries. In this work, Sb2WO6 with nanosheets morphology was successfully synthesized using a simple microwave hydrothermal method and systematically studied as an anode for lithium-ion batteries. The optimal SWO (SWO-60) exhibits a high specific discharge capacity and good rate capability. The good electrochemical performance could be ascribed to mesoporous nanosheets morphology, which is favorable for the penetration of the electrolyte and charge transportation. The results show that this nanostructured SWO is a promising anode material for LIBs.

Construction of NiMoO4 nanorods@ZIF-67 derived Co3O4 supported on cellulose based carbon aerogel for asymmetric supercapacitors

In this study, NiMoO4 nanorods @ ZIF-67 derived Co3O4 material supported by cellulose based carbon aerogel (CA) is successfully synthesized by two-step hydrothermal method. Benefitting from hierarchical porous structure, large specific surface and chemical composition, the NiMoO4@Co3O4/CA ternary composite electrode delivers an enhanced specific capacitance of 1092.1 F/g at 0.5 A/g with the good rate capability (70.7% capacitance retention at 5.0 A/g). Besides, an advanced asymmetric supercapacitors (ASCs) is assembled by using the as-prepared NiMoO4@Co3O4/CA ternary composite as a positive electrode and activated carbon (AC) as negative. The results suggest that the ASCs device exhibits a large capacitance of 125.4 F/g at 0.5 A/g, a highest energy density of 34.1 Wh/kg at a power density of 208.8 W/kg as well as cycling stability (84% after 2000 cycles), suggesting its great applications in energy storage. Namely, our results may provide a general approach to construct carbon aerogel and various MOF based composite materials with hierarchical porous structure for potential applications in supercapacitor.

Effect of Acids on Synthesis of WO3 and their Application in Supercapacitor

In this study, the characteristics of WO3 prepared with acidic solution were analyzed. The acidic solution was prepared by using hydrochloric acid and sulfuric acid as the solutions to be added during the hydrothermal synthesis process. SEM, XRD and electrochemical characteristics tests were performed based on the prepared samples. Samples prepared in hydrochloric acid (W1) solution can identify platelet crystals and nanospheres, and samples made from sulfuric acid (W2) solutions can identify nanospheres and nanocubes. From the XRD data, it was confirmed that all of the diffraction peaks had a hexagonal phase. Electrochemical properties showed good rate capability of W1 samples but low capacitance and W2 samples showed relatively high capacitances.

Preparation of urchin-like NiCo2O4 material and studies of its electrochemical performance for supercapacitors

The paper reports a kind of NiCo2O4 material with urchin-like morphology. This material was prepared using a facile strategy of hydrothermal process followed by calcinations, and exhibits an excellent electrochemical performance. For example, it delivers a specific capacitance high up to 1167[Formula: see text]Fg[Formula: see text] at 1[Formula: see text]Ag[Formula: see text] and still retains a value of 1095[Formula: see text]Fg[Formula: see text] at 10[Formula: see text]Ag[Formula: see text], showing a good rate capability; after suffering from 3000 cycles at 10[Formula: see text]A[Formula: see text]g[Formula: see text], the specific capacitance has only a decay of 12%, presenting a good cycling stability.