Ali Bahadur

Electrochemical performance of 2D polyaniline anchored CuS/Graphene nano-active composite as anode material for lithium-ion battery

Lithium-ion battery (LIB) is a revolutionary step in the electric energy storage technology for making green environment. In the present communication, a LIB anode material was constructed by using graphene/polyaniline/CuS nanocomposite (GR/PANI/CuS NC) as a high-performance electrode. Initially, pure covellite CuS nanoplates (NPs) of the hexagonal structure were synthesized by hydrothermal route and then GR/PANI/CuS NC was fabricated by in-situ polymerization of aniline in the presence of CuS NPs and graphene nanosheets (GR NSs) as host matrix. GR/PANI/CuS NC-based LIB has shown the superior reversible current capacity of 1255mAhg-1, a high cycling stability with more than 99% coulombic efficiency over 250 cycles even at a high current density of 5Ag-1, low volume expansion, and excellent power capabilities. Galvanostatic charge/discharge tests and cyclic voltammetry analysis were used to investigate electrochemical properties. The electrochemical test proves that GR/PANI/CuS NC is promising anode material for LIB. The crystal phases and purity of the GR/PANI/CuS NC were confirmed by X-ray diffraction (XRD). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) were employed to examine the morphology, size, chemical composition, and phase structure of the synthesized GR/PANI/CuS NC.

FT-IR spectroscopic and thermal study of waterborne polyurethane-acrylate leather coatings using tartaric acid as an ionomer

Abstract Waterborne polyurethane (WDPU) comprising polycaprolactone diol and hexamethylene diisocyanate was prepared by using tartaric acid (TA) as an ionomer. WDPU was further modified with polymethyl methacrylate (PMMA). Hybrid WDPU-PMMA coatings were formed by using unsaturate end capping agents such as 2-hydroxyethylmethacrylate. WDPU-PMMA blend coatings were formed by using chain extenders such as ethylene glycol, ethylene diamine and mixed with PMMA. Thermal behavior and structural characterizations were investigated by means of thermogravimetric analysis and Fourier transformm infrared (FT-IR) spectroscopy, respectively. Chemical and solvent resistance was checked against various chemicals and solvents. Bio-stability was evaluated in CoCl2/H2O2 solution. Gloss, film flexibility, tackiness, abrasion resistance and adhesive prosperities of WDPU-PMMA coatings were also checked by applying these coatings on a leather sheet.

Synthesis of thermally and mechanically improved polyurethane-urea elastomers by using novel diamines as chain extenders

Abstract This article reports the synthesis of novel diamines as chain extenders for the improvement of thermal and mechanical properties of polyurethane (PU). Three novel diamine, 1,2-di(p-aminophenoxy)ethane (BAE), 1,2-di(p-aminophenoxy)propane (BAP) and 2,2-bis(p-(p-aminophenoxy)phenyl)propane (BAPP) were synthesized as chain extenders. Formation of diamines and their reaction with PU prepolymer was analyzed by using Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy. The conversion of the free isocyanate group (NCO) into a urethane-urea group was confirmed through the disappearance of the isocyanate peak at 2244 cm-1. The thermogravimetric analysis (TGA) reveals the thermal stabilization effect of urethane-urea hard segments of the polyurethane system. From the SAXS investigations, the hard segment inter-domain spacing (d) was calculated, which was 24 nm for the reference sample, and 25, 26, and 28.5 nm for the synthesized PU systems. Mechanical test shows an increase in the Young’s modulus and yield strength with BAE and BAP diamines, while BAPP diamine based systems reveal lower modulus values as compared to the reference sample.

Electrochemical study of specially designed graphene-Fe3O4-polyaniline nanocomposite as a high-performance anode for lithium-ion battery

In this work, an anode material with improved thermal stability, charge capacity, charge capacity retention, energy density, cyclic performance, operation safety, reversible capacity, and rate capability was synthesized for battery applications. The graphene-magnetite-polyaniline (Gr-Fe3O4-PANI) nanocomposites (NCs) are believed to deliver outstanding performance owing to the collective effect of the layered graphene (Gr) and magnetite (Fe3O4) hollow rods (HRs), as well as the better conductivity of polyaniline (PANI). The Gr-Fe3O4-PANI NCs easily enable the insertion and deinsertion of Li+, the passage of ions in the electrode, fast kinetics of Li+, and low volume expansion. Gr-Fe3O4-PANI NC was prepared by polymerizing aniline in the presence of already prepared Fe3O4 HRs, then dispersing in Gr. Fe3O4 HRs were synthesized by a hydrothermal route. Electrochemical properties were investigated by galvanostatic charge-discharge analysis and cyclic voltammetry. A lithium-ion battery (LIB) based on the Gr-Fe3O4-PANI exhibited a superior reversible current capacity of 1214 mA h g-1, excellent power capability, low volume expansion, high cycling stability and 99.6% coulombic efficiency over 250 cycles.