Anode materials for lithium-ion batteries: A review

The need for eco-friendly and portable energy sources for application in electrical, electronic, automobile and even aerospace industries has led to an ever-increasing research and innovation in lithium-ion battery technology. Owing to the research and discoveries in recent years, lithium-ion batteries (LIBs) have stood out as the most suitable device for the storage of electrical power for application in mobile appliances and electric vehicles. This is as a result of the very attractive properties inherent in LIBs, which include lightweight, high energy density, small-scale size, few memory effects, long cycle life and low pollution. In this review article, recent advances in the development of anode materials for LIBs will be discussed, along with their advantages and disadvantages. New approaches for alleviating the drawbacks associated with LIB anode materials will also be highlighted

Photovoltaic efficiencies of microwave and Cu2ZnSnS4 (CZTS) superstrate solar cells

Organic and inorganic materials such as perovskites, copper indium gallium diselenide, cadmium telluride, and copper zinc tin sulfide/selenide (CZTS/Se) have been employed to capture unlimited sunlight through the photovoltaic effect. CZTS/Se is regarded as the most promising, most environmentally friendly, most abundant candidate with high absorption coefficient and tunable bandgap for the generation of solar energy. Superstrate architectures have numerous advantages over the substrate architectures and for this reason; it offers a promising route for producing solar cells at a relatively low cost. This article reviews the state-of-the-art knowledge on the synthesis, crystal structure, electronic properties, defects, and secondary phases of CZTS. The CZTS solar cell device architecture and mechanism of the substrate and superstrate configurations were also covered in the review. The preparation of superstrate CZTS via vacuum and non-vacuum methods, as well as their photovoltaic efficiencies were critically discussed. The microwave synthesis and characterization of CZTS nanoparticles were also reviewed with respect to the effect of temperature, surfactant, and reagents on the physical properties of the nanomaterials. The application of microwave-synthesized CZTS nanoparticles in the advancement of thin film solar cells was also critically examined. Finally, the challenges and the prospects of CZTS solar cells were also presente

Copper-modified carbon nano-onions as electrode modifiers for the electroanalysis of the antiretroviral drug Efavirenz

The high prescription and consumption rate of antiretroviral drugs (ARV) such as Efavirenz (EFV) in South Africa for the treatment of the human immunodeficiency virus (HIV) has resulted in its presence in wastewater and surface water. Herein we report the electroanalysis of EFV at oxidised boron-nitrogen doped carbon nano-onions (oxi-BNCNO) and microscale branched copper cluster (CuC) modified glassy carbon electrodes. Potentiostatic electrodeposition of CuC on the oxi-BNCNO/GCE platform resulted in a stable and electrocatalytic surface that accelerated electron transfer between the analyte and the CuC/oxi-BNCNO/GCE surface, making quantification efficient. The electroactive surface area of CuC/oxi-BNCNO/GCE was estimated as being 3 times higher than bare GCE and twice that of oxi-BNCNO/GCE. The electrooxidation of EFV on a CuC/oxi-BNCNO/GCE sensor resulted in a pH-dependant anodic peak in the potential range of 0.8 to 1.2 V vs Ag/AgCl (3M KCl). The EFV voltammetric signal increased linearly with increasing concentration of EFV in the linear dynamic range (LDR) of 0.01 – 1.0 µM and 0.5 – 20 µM with a limit of detection (LOD) and quantification (LOQ) of 1.2 and 3.97 nM, respectively. Moreover, the sensor had a sensitivity of 23 µA • cm− 2 • µM− 1 and was selective to 100-fold of interferents including heavy metal ions and other ARVs with the exception of high concentrations of nevirapine. The developed electroanalytical method was successfully applied for the determination of EFV in real samples such as wastewater influent and effluent, drinking/tap water, and a pharmaceutical formulation with recovery ranging from 97.8% to 109.5%

AC voltammetric transductions and sensor application of a novel dendritic poly(propylene thiophenoimine)-co-poly(3-hexylthiophene) star co-polymer

The contamination of surface and underground water by polyaromatic hydrocarbons (PAHs), such asphenanthrene, presents significant latent risk to humans and the ecosystem through the food chain. Oneof the sources of PAH pollution is the activities of the oil industry. A novel dendritic star-copolymer sensorsystem (Au|G3PPT-co-P3HT) for the determination of phenanthrene (PHE) in oil-polluted wastewater wasprepared by in situ electrochemical co-polymerization of generation 3 poly(propylene thiophenoimine)(G3PPT) and poly(3-hexylthiophene) (P3TH) on a gold electrode. Electrochemical characterization and sensor application of the Au|G3PPT-co-P3HT electrode were performed by alternating current voltammetry (ACV), in a supporting electrolyte of 0.1 M Bu4NClO4in acetonitrile. The sensor parameters includea dynamic linear range (DLR) of application values of 2.78-7.65 nM and a limit of detection (LOD) of1.42 nM (0.253 ppb). The WHO guideline value for PAHs is 0.7 ppb, which falls within the DLR of thedendrimeric sensor for PHE. The Au|G3PPT-co-P3HT was sensitive to PHE determination in oil-polluted wastewater.

Electro-oxidation of anthracene on polyanilino-graphene composite electrode

A novel graphenated-polyaniline (GR-PANI) nanocomposite sensor was constructed and used for the determination of anthracene. The direct electro-oxidation behavior of anthracene on the GR-PANI modified glassy carbon electrode (GCE) was used as the sensing principle. The results indicate that the responseprofile of the oxidation of anthracene on GR-PANI-modified GCE provides for the construction of sensor systems based on amperometric and voltammetric signal transductions.

Graphenated polyaniline-doped tungsten oxide nanocomposite sensor for real time determination of phenanthrene

A graphenated polyaniline/tungsten oxide (PANI/WO3/GR) nanocomposite sensor was prepared by elec-tropolymerisation of a mixture of aniline monomer and tungsten oxide on a graphene-modified glassycarbon electrode (GCE). The PANI/WO3/GR/GCE nanocomposite electrode was tested as a sensor for the determination of phenanthrene. The direct electro-oxidation behaviour of phenanthrene on thePANI/WO3/GR modified GCE was carefully investigated by cyclic voltammetry. The results indicated that the PANI/WO3/GR/GCE sensor was more sensitive to phenanthrene (with a dynamic linear range of 1.0 -6.0 pM and a detection limit of 0.123 pM.) than GCE, PANI/GCE or PANI/WO3/GCE. The sensor exhibited excellent reproducibility and long-term stability. The sensor exhibits lower detection sensitivity than the WHO permissible level of 1.12 nM phenanthrene in waste water.