Three-dimensional ZnS/reduced graphene oxide/polypyrrole composite for high-performance supercapacitors and lithium-ion battery electrode material

Insight into the Role of Conductive Polypyrrole Coated on Rice Husk-Derived Nanosilica-Reduced Graphene Oxide as the Anodes: Electrochemical Improvement in Sustainable Lithium-Ion Batteries

Polypyrrole (PPy) is a type of conducting polymer that has garnered attention as a potential electrode material for sustainable energy storage devices. This is mostly attributed to its mechanical flexibility, ease of processing, and ecologically friendly nature. Here, a polypyrrole-coated rice husk-derived nanosilica-reduced graphene oxide nanocomposite (SiO2-rGO@PPy) as an anode material was developed by a simple composite technique followed by an in situ polymerization process. The architecture of reduced graphene oxide offers a larger electrode/electrolyte interface to promote charge-transfer reactions and provides sufficient space to buffer a large volume expansion of SiO2, maintaining the mechanical integrity of the overall electrode during the lithiation/delithiation process. Moreover, the conducting polymer coating not only improves the capacity of SiO2, but also suppresses the volume expansion and rapid capacity fading caused by serious pulverization. The present anode material shows a remarkable specific reversible capacity of 523 mAh g-1 at 100 mA g-1 current density and exhibits exceptional discharge rate capability. The cycling stability at a current density of 100 mA g-1 shows 81.6% capacity retention and high Coulombic efficiency after 250 charge-discharge cycles. The study also pointed out that this method might be able to be used on a large scale in the lithium-ion battery industry, which could have a big effect on its long-term viability. Creating sustainable nanocomposites is an exciting area of research that could help solve some of the biggest problems with lithium-ion batteries, like how easy they are to make and how big they can be used in industry. This is because they are sustainable and have less of an impact on the environment.

Fe3O4@MIL-100(Fe) modified ZnS nanoparticles with enhanced sonocatalytic degradation of tetracycline antibiotic in water

Sonocatalysis has attracted excellent research attention to eradicate hazardous pollutants from the environment effectively. This work synthesised an organic/inorganic hybrid composite catalyst by coupling Fe3O4@MIL-100(Fe) (FM) with ZnS nanoparticles using the solvothermal evaporation method. Remarkably, the composite material delivered significantly enhanced sonocatalytic efficiency for removing tetracycline (TC) antibiotics in the presence of H2O2 compared to bare ZnS nanoparticles. By adjusting different parameters such as TC concentration, catalyst dosage and H2O2 amount, the optimized composite (20 %Fe3O4@MIL-100(Fe)/ZnS) removed 78.25% antibiotic in 20 min at the cost of 1 mL of H2O2. These much superior activities are attributed to the efficient interface contact, effective charge transfer, accelerated transport capabilities and strong redox potential for the superior acoustic catalytic performance of FM/ZnS composite systems. Based on various characterization, free radical capture experiments and energy band structures, we proposed a mechanism for the sonocatalytic degradation of tetracycline based on S-scheme heterojunctions and Fenton like reactions. This work will provide an important reference for developing ZnS-based nanomaterials to study sonodegradation of pollutants.

Multifunctional ionic liquid-assisted interfacial engineering towards ZnS nanodots with ultrastable high-rate lithium storage performance

In this article, a new zinc-containing ionic liquid (IL) [HMMIm]₂[ZnCl₄] (HMMIm = 1-hexyl-2,3-dimethyl-imidazolium) is designed, which acts as a multifunctional source for the interfacial engineering of ZnS nanodots (NDs). Given the electrostatic interaction driven by the imidazolium cation, the steric effect of the alkyl chain, and the in situ released Zn ion from the IL, [HMMIm]₂[ZnCl₄] shows great advantages in controlling the formation of ZnS NDs. Based on this strategy, a nanocomposite consisting of homodispersed ZnS NDs anchored on sulfur/nitrogen dual-doped reduced graphene oxide (ZnS-NDs@SNG) is prepared. When evaluated as an anode material for lithium-ion batteries (LIBs), the nanocomposite delivers high reversible specific capacity, excellent high-rate performance, and superior cycling life. In particular, a discharge capacity of 648.1 mA h g^-1 can be achieved at a high current density (10.0 A g^-1) over 5000 cycles. Benefitting from the multifunctional IL and the simple synthesis protocol, the IL-assisted interfacial engineering strategy will enable a new avenue for the controllable synthesis of metal-sulfide-based anode materials.

Intrinsically conducting polymers and their combinations with redox-active molecules for rechargeable battery electrodes: an update

Intrinsically conducting polymers and their copolymers and composites with redox-active organic molecules prepared by chemical as well as electrochemical polymerization may yield active masses without additional binder and conducting agents for secondary battery electrodes possibly utilizing the advantageous properties of both constituents are discussed. Beyond these possibilities these polymers have found many applications and functions for various further purposes in secondary batteries, as binders, as protective coatings limiting active material corrosion, unwanted dissolution of active mass ingredients or migration of electrode reaction participants. Selected highlights from this rapidly developing and very diverse field are presented. Possible developments and future directions are outlined.

The in situ construction of three-dimensional core–shell-structured TiO2@PPy/rGO nanocomposites for improved supercapacitor electrode performance

Three-dimensional core–shell-structured TiO₂@PPy/rGO nanocomposites can be used as ideal electrodes with a longer discharge time and higher capacitance.

Preparation of cobalt sulfide@reduced graphene oxide nanocomposites with outstanding electrochemical behavior for lithium-ion batteries

Cobalt sulfide@reduced graphene oxide composites were prepared through a simple solvothermal method. The cobalt sulfide@reduced graphene oxide composites are composed of cobalt sulfide nanoparticles uniformly attached on both sides of reduced graphene oxide. Some favorable electrochemical performances in specific capacity, cycling performance, and rate capability are achieved using the porous nanocomposites as an anode for lithium-ion batteries. In a half-cell, it exhibits a high specific capacity of 1253.9 mA h g-1 at 500 mA g-1 after 100 cycles. A full cell consists of the cobalt sulfide@reduced graphene oxide nanocomposite anode and a commercial LiCoO2 cathode, and is able to hold a high capacity of 574.7 mA h g-1 at 200 mA g-1 after 200 cycles. The reduced graphene oxide plays a key role in enhancing the electrical conductivity of the electrode materials; and it effectively prevents the cobalt sulfide nanoparticles from dropping off the electrode and buffers the volume variation during the discharge-charge process. The cobalt sulfide@reduced graphene oxide nanocomposites present great potential to be a promising anode material for lithium-ion batteries.

Investigation on the role of different conductive polymers in supercapacitors based on a zinc sulfide/reduced graphene oxide/conductive polymer ternary composite electrode

Conductive polymers, such as polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh) and poly 3,4-ethylenedioxythiophene (PEDOT), play an important role in the application of pseudocapacitors. It is necessary to explore the effects of different conductive polymers in electrode composites. Herein, we prepare zinc sulfide/reduced graphene oxide (ZnS/RGO) by the hydrothermal method, and conductive polymers (PANI, PPy, PTh and PEDOT) doped with the same mass ratio (polymer to 70 wt%) via in situ polymerization on the surface of ZnS/RGO composite. For the supercapacitor application, the ZnS/RGO/PANI ternary electrode composite possesses the best capacitance performance and cycle stability out of all of the polymer-coated ZnS/RGO composites. In the three-electrode system, the discharge specific capacitance and cycle stability of ZnS/RGO/PANI are 1045.3 F g-1 and 160% at 1 A g-1 after 1000 loops. In a two-electrode symmetric system, the discharge specific capacitance and cycle stability of ZnS/RGO/PANI are 722.0 F g-1 and 76.1% at 1 A g-1 after 1000 loops, and the greatest energy and power density of the ZnS/RGO/PANI electrode are 349.7 W h kg-1 and 18.0 kW kg-1. In addition, conductive polymers can effectively improve the voltage range of the electrode composites in 6 M KOH electrolyte for the two-electrode system. The discharge voltage ∼1.6 V makes them promising electrode materials for supercapacitors.