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In this study, mild steel was treated with SDBS:ZnSO4 compound by immersing the mild steel substrates in a SDBS:ZnSO4 bath of varying pH. The effect of bath solution pH and immersion time on the corrosion protection properties of SDBS:ZnSO4 pre-treated mild steel in sodium chloride solution was investigated using electrochemical impedance spectroscopy (EIS) and polarization measurements. From the EIS results, it was found that the inhibition efficiency provided by the pre-treatment was significantly affected by the pH of the bath solution, where inhibition was highest at pH 6. This is due to the formation of a good protective layer on mild steel substrate caused by the deposition of zinc hydroxide/oxide and SDBS compound. Increasing the immersion time from 1 h to 24 h increased the inhibition efficiency. From the polarization measurements, the current density was significantly reduced, and the shift to a more positive corrosion potential value indicated a higher protection layer was formed on the metal surface during more prolonged immersion. It has been found that longer pre-treatment immersion time allows a denser protective layer formed, which prevented the diffusion of water towards the mild steel substrate that can lead to corrosion.

This study focuses on preparation and characterization of polymer gel electrolytes (PGEs) based on agarose–LiBOB–DMSO and poly(1-vinylpyrrolidone-co-vinyl acetate)–LiBOB–DMSO. Two systems of PGEs were prepared by dissolving a different amount (1-8 wt.%) of agarose and (1-8 wt.%) P(VP-co-VAc) as host polymer in 0.8 M of LiBOB–DMSO solution. The addition of host polymer into 0.8 M of LiBOB–DMSO solution will result an optimum conductivity which is 6.91 x 10-3 S.cm-1 for agarose–LiBOB–DMSO system and 7.83 x 10-3 S.cm-1 for P(VP-co-VAc)–LiBOB–DMSO system. In the temperature range of conductivity studies discovered that the agarose–LiBOB–DMSO and P(VP-co-VAc)–LiBOB–DMSO polymer gel electrolytes abide by Arrhenius rule indicating that this PGEs could run at elevated temperature conditions. Furthermore, lithium transference number confirms that both electrolyte systems have 0.03 and 0.12 respectively at room temperature (298 K). Linear sweep voltammetry (LSV) measurements demonstrate the agarose–LiBOB–DMSO system has a potential of 4.26 V and P(VP-co-VAc)–LiBOB–DMSO system has a potential of 4.50 V which is good in electrochemical stability.

In this work, single phase Bismuth Ferrite, BiFeO3 was successfully synthesized by using hydrothermal method assisted with different weight (0.24 g, 0.36 g and 0.48 g) of Chitosan. Potassium hydroxide (KOH) were used as a mineralizer during the synthesis process for the precipitation. The samples were characterized for different properties such as structural and optical properties, and were then compared with previous works. The X-ray diffraction data for all the samples showed that the samples had a single phase belonging to R3c space group with perovskite rhombohedral structure at diffraction angle 32.0° to 32.5° even though the slight presence of secondary phase at diffraction angle 28° was detected. Scanning electron microscope revealed a decrement in particle size as the weight of Chitosan increased indicating effective used of Chitosan in controlling the agglomeration of the particles. All samples BiFeO3 assisted with and without Chitosan showed significant enhancement in energy gap where the obtained results showed a small energy gap values ranging from ~1.22 eV to ~1.88 eV determined from UV-vis absorbance characterization. Therefore, by the addition of Chitosan, the properties of BiFeO3 such as structural and optical have changed as well as preventing from the particle to agglomerate.

Graphene-Zinc Oxide (Gr-ZnO) nanocomposites films were successfully synthesized via facile electrodeposition method in an aqueous solution under Gr concentration conditions. Gr, as a highly conductive carbon, acts as an anchor for ZnO nanosheets and plays a substantial role in controlling the degree of dispersion of ZnO nanosheets onto indium-doped tin oxide (ITO) substrate to form Gr-ZnO nanocomposite. Atomic force microscopy (AFM) and field-emission scanning electron microscopy (FESEM) analysis of Gr-ZnO nanocomposite samples confirmed that the presence of ZnO nanosheets with a high degree of dispersity and crystallinity which is well linked to the thin layer of Gr nanoparticle on ITO substrate. The surface roughness of the films found increased to ~270 nm on Gr-ZnO as compared to Gr ~44 nm and ZnO ~3 nm. Further, the x-ray diffraction spectroscopy (XRD) analysis showed the result is in good agreement with Raman spectroscopy study. The cyclic voltammetry (CV) of Gr-ZnO nanocomposite revealed that the effect of electron-hole recombination process was increased and the presence of Gr in ZnO photoanode provides the fastest redox reaction and hence offers the fastest electron transfer in photoanode.

The morphology and electrochemical properties of electrodes made from graphene (Gr)-activated carbon (AC) composite (GrAC) doped with iron(III) tetramethoxyphenylporphyrin chloride (FeTMPP-Cl), hereafter referred to as GrAC-FeTMPP-Cl, are investigated in this study. The properties of the modified electrodes are considerably improved by modifying carbon through the introduction of transition metal catalysts into the hybrid carbon matrix. The hybrid GrAC exhibits superior electrochemical properties than those of materials with single components. Incorporating AC into Gr nanosheets prevents the aggregation of the nanosheets because the AC particles distributed between the Gr layers provide numerous pathways for electron transfer. The addition of FeTMPP-Cl to the electrode material, followed by pyrolysis, enhances the material’s electrochemical properties, including fast electron transfer, low charge transfer resistance and high redox current peaks, due to numerous accessible effective surface areas of the electrode. The pyrolysed GrAC-FeTMPP-Cl-modified electrode achieves the highest oxidation current peak of 0.088 mA, with an increment of 10.3% compared with GrAC (0.080 mA) at a scan rate of 20 mVs−1 in 5 mM K3 [Fe(CN)6]/0.1 M KCl electrolyte solution. Results demonstrate the high potential for applications of the pyrolysed GrAC-FeTMPP-Cl/indium tin oxide modified electrode in flexible energy storage devices.

Structural, electronic, and optical properties of ternary vanadium sulfides, XV2S4 (X = Ni, Cr, and Mo), are investigated using first-principles calculations based on density functional theory (DFT) method. The structural parameters, band structures, density of states (DOS), absorption coefficient, and conductivity are reported to discuss the properties of XV2S4 (X = Ni, Cr, and Mo) as potential Pt-free counter electrode for dye-sensitized solar cell (DSSC). Generally, nickel vanadium sulfide (NiV2S4) is predicted to be a good candidate as a counter electrode compares with chromium vanadium sulfide (CrV2S4) and molybdenum vanadium sulfide (MoV2S4) due to its ability to provide high electron density around Fermi level and high conductivity.

This study explored the electronic and optical properties of nano-thin film orthorhombic bismuth selenide (Bi2Se3) using first-principles approach. The thin films were modelled in the [001] direction using slab geometry supercell with vacuum along z-direction so that periodic images and slab can be managed independently. We obtained band gap of 0.730 eV, 0.566 eV and 0.690 eV for 1, 2 and 3 slabs respectively. It shows dependence of band structure to the thickness of the films. The reduced band gap in Bi2Se3 films is due to the effect of quantum confinement. The electron contributions were increased as the thickness of the thin film increased. We also found that the thickness of Bi2Se3 thin film influences its optical properties. Higher thickness provides higher static dielectric function, refractive index, extinction coefficient, absorption coefficient and loss function. This study demonstrates Bi2Se3 thin film has good optical properties that are useful for optoelectronic applications.

Good thermoelectric performance is being sought to face major problems related to energy, especially in the concern of the usage of energy on environmental impact. In this work, we investigate the underlying mechanism to enhance the thermoelectric performance of bismuth selenide (Bi2Se3) by employing density functional theory (DFT) followed by the Boltzmann transport equation under relaxation time approximation. The structural, electronic, and thermoelectric properties were calculated and analyzed. From the analysis of combined results of thermoelectric properties and electronic properties as the function of the Fermi level, we found that the power factor of Bi2Se3 is improved by increasing electrical conductivity that contributed by the large density of states and light effective mass of charge carriers. The figure of merit, on the other hand, is enhanced by increasing Seebeck coefficient that contributed by heavy effective mass and decreasing thermal conductivity that contributed by low density of states. We also found that both power factor and figure of merit can be improved through n-type doping at 300 K and p-type doping at higher temperature (400 K and 500 K).

The increasing energy demand on available global lithium resources has created concerns on development of new and advanced sustainable energy sources. Sodium-based batteries have emerged as promising substitutions to Li-based batteries. We describe here sodium trifluoromethanesulfonate (NaCF3SO3) electrolyte system based on tetraethylene glycol dimethyl ether (tetraglyme). The ionic conductivity of the electrolytes showed a maximum value of 1.6 mS cm−1 for 40 mol% of NaCF3SO3 at room temperature and increased up to of 9.5 mS cm−1 at 373 K. The system showed the anodic stability of the electrolytes up to ca. 5.2 V (Na+/Na) and facile deposition of sodium began at relatively low overpotential, around − 0.01 V vs. Na+/Na, which showed a good reversibility of the electrolytes. Preliminary tests of the electrolyte in half sodium-ion cells employing Na3V2(PO4)3 as cathode electrodes were performed and the cells delivered capacity of 74 mAh g−1 at C/10.

Gun powder is predicted to be more expensive in relation to the world oil shortage crisis in the future. However, cellulose (generic chemical formula (C6H10O5) is the carbohydrate that makes up the main structure of plants. It is more economical especially for countries with a lot of natural resources and rain forests like Malaysia. The finding of the study reveals the capability of nitrocellulose as gunpowder. In this research, a comparison of the same mass of nitrocellulose and gunpowder is made to find out which propellant produce longer distance and greater impact. The main objectives of this study are to find out the performance and capability of nitrocellulose extracted from Rhizophora apiculata compared to gunpowder in terms of velocity, calorific value of bullets and kinetic energy produced. The result shows that the nitrocellulose has better performance than gun powder. The new application of smokeless gun powder ensures troops especially snipers hardly being detected by enemy and at the same time improves safety and security level.

Electrical dielectric spectra and alternating current (ac) conductivity of blended poly (N-vinlycarbazole) (PVK) with polyvinylpyrrolidone (PVP) at different temperature are investigated. The polymer blends were prepared by dissolving in dimethylformamide (DMF) using drop casting method and further dried in vacuum oven. The dielectric and ac conductivity of each sample was investigated using electrochemical impedance spectroscopy (EIS) method. Dielectric permittivity studies revealed that there are significant changes in the spectra at different temperature. The ac conductivity was further analyzed by using universal power law. The hopping parameter was calculated by using correlated barrier hopping model.

Sodium-based batteries have emerged as promising alternatives to Li-based batteries for future safe, high energy-density energy storage. They are expected to be cheaper, due to the greater abundance of Na and likely reduction in raw material costs. In this study, we investigate the properties of superconcentrated sodium bis(fluorosulfonyl)amide (NaFSI) mixtures with the ionic liquid (IL) methylpropylpyrrolinium (C 3 mpyr) FSI in the presence of ethylene carbonate (EC) in the liquid and gel states. Ionic conductivity and thermal stability are evaluated through electrochemical impedance spectroscopy (EIS) and differential scanning calorimetry (DSC), respectively. NaFSI is soluble in the IL up to 55 mol% Na; adding EC (30 wt.%) to the IL almost doubles the ionic conductivity at ambient temperature. The temperature dependence of conductivity is well described by the Vogel-Tamman-Fulcher equation. NMR spectroscopy and Pulse Field Gradient NMR diffusion were employed to investigate transport in these electrolyte systems, while the chemical interactions were also studied using ATR-FTIR. Stable plasticized gel electrolytes were observed, even at 30 wt. % EC; the formation of the gel does not significantly affect the liquid-like ion dynamics in these materials, as shown by DSC and FTIR analysis. The Na + transference number of Na 0 . 55 [C 3 mpyr] 0.45 [FSI] + 30 wt.% EC was up to 0.32, and deposition and dissolution of sodium metal were observed in cyclic voltammetry around 0 V vs. Na/Na + . Moreover, the suitability of the prepared electrolyte is preliminarily verified in half-cells at room temperature using Na 3 V 2 (PO 4 ) 3 as a cathode. The cells delivered capacity of 52.4 mAhg −1 at C/20.

First-principles calculations are performed to study the electronic properties of zinc oxide (ZnO) formed on an anode after discharging a Zn–air system. Prior to calculation, the ZnO is characterised by X-ray diffraction using Rietveld refinement. Diffracted patterns proved the formation of single phase ZnO, while Rietveld analysis shows that the ZnO has a hexagonal wurtzite structure with lattice parameters, a = 3.244 and c = 5.199 A. Geometry optimisation of the hexagonal wurtzite structure of the ZnO is performed using various exchange–correlation energy functionals. The local density approximation functional method is used to explain the structure, electronic band structure and density of state properties of hexagonal ZnO. The calculated energy band gap was 0.75 eV while the density of states reveals that the O 2p (the top valence band) and Zn 4s (the bottom conduction band) states domination.

0.5 wt.% of N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD) was introduced into polymer electrolytes based on 30% poly(methyl-methacrylate) grafted natural rubber (MG30) in order to reduce the aging factor of MG30. The polymer electrolyte without 6PPD was used as control. All samples were prepared by using solution cast techniques. The effect of 6PPD in the electrolytes was analysed by using TGA, DSC and FTIR. TGA and DSC results revealed the thermal stability of MG30 electrolytes with 6PPD have higher thermal stability but lower glass transition temperature value. FTIR studies confirmed the existence of LiTF in the sample and prove the occurrence of polymer-salt complexation. Deconvolution techniques analysis on FTIR spectra shows the electrolyte sample with 6PPD display more ion dissociation which reflects to higher ionic conductivity.

Graphene is a material that has been heavily investigated in many researches due to its beneficial characteristics such as large surface area, low manufacturing cost, high electro conductivity and incredible mechanical strength. Applying the graphene in water-based solvents however can cause agglomeration due to its hydrophobic properties. Researchers have composited the graphene with other materials in overcoming its hydrophobicity. In this research, graphene was nanocomposited with thionine to make it disperse well in water-based solvents while preserving its intrinsic properties. The nanocomposition process involves mixing of both graphene oxide with thionine and were reduced by hydrazine hydrate while reflux heating. The produced mixture was then filtered to obtain the Thionine-Graphene nanocomposite. The obtained sample was then characterized to confirm the composition of both graphene and thionine. Fourier transfer infrared spectroscopy was operated to investigate the chemical bonds and hence concluding the presence of both graphene and thionine in the sample. The preservation of the intrinsic properties of graphene was also investigated through observing the absence of functionalized graphene bonds. Post-investigation reports that the chemical bonds from both of the materials, graphene and thionine were detected confirming the successfulness of the nanocomposition.

Proton exchange membrane materials based on sulfonated poly ether ether ketone (SPEEK) with Methyl Cellulose (MC) are developed by solution cast technique and exposed to UV radiation with Bezoin Ethyl Ether (BEE) as photoinitiator. The addition of MC into SPEEK polymer enhances the conductivity up to 8.7 × 10−3 Scm−1 at 30 °C temperature and 80% relative humidity. This new crosslinked hybrid membrane shows good prospect for the use as proton exchange membrane in fuel cell.

Objectives: The aims of this paper was to produce hydroxyl hypercrosslinked polymers with high specific surface area derived from poly(HEMA- co -EGDMA- co -VBC) precursor beads. Methods: This was achieved using hyper crosslinking reaction and the beads were characterized by FTIR, SEM and BET analysis. Findings: The BET analysis showed that specific surface area increasing from ~5 m 2 /g to 310 m 2 /g when amount of VBC increased up to 90 wt%. However, when amount of EGDMA increasing from 40 wt% to 100 wt%, specific surface area decreasing from 310 m 2 /g to ~61 m 2 /g. SEM images also showed that when increasing EGDMA content, hypercrosslinked polymer still can retain precursor shape with satisfied quality. The catalyst ratio was varied between 1:1 to 3:1 mole ratio (based on -CH 2 Cl content) and from the results obtained, there are no significant effect on specific surface area and morphology of hypercrosslinked polymer when ratio of catalyst increased. From FTIR spectra, reduction peak at 1265 cm -1 resulted from methylene bridges formed in all experiments proved that hypercrosslinking reaction was successfully carried out. Application/Improvement: Hypercrosslinked polymer will be used in functionalization reaction to produce quaternary ammonium resin.

This work aims to investigate effects of vanadium substitution on structural and electronic properties of the pristine LiFeSO 4 OH compound using GGA, GGA+U and GGA + van der Waals (vDW) dispersion corrections. Upon vanadium substitution, the band gap of substituted vanadium on LiFeSO 4 OH decreased implying the increase in electronic conductivity, thus a good property for a cathode material. Moreover, the volume of substituted material also increased suggesting ease movement of lithium ions within the host structure thus increasing the ionic conductivity. Since no experimental structure of this material has been reported, therefore the structure of current layered LiFeSO 4 OH is adopted. Furthermore, electronic properties viz. the lattice parameter, density of state (DOS), bond length (BL), bond order (BO) and charge density were also determined using the first principles approach.

First principles calculations on structural, electronic and optical properties of the orthorhombic phase (No. 62: Pnma space group) lead-free Sn(II) hybrid halide perovskite CH3NH3SnI3 were systematically carried out. Work on Pb(II)-based CH3NH3PbI3 hybrid halide perovskite of the same space group is also included for comparative purposes. All calculations were performed using the local density approximation (LDA) and the generalized gradient approximation (GGA) schemes. The obtained lattice parameters and cell volumes are consistent with the available experimental data and other theoretical works. According to the electronic band structure, both of the semiconductor compounds have a direct band gap. A band gap of 0.935 eV yielded for CH3NH3SnI3 compound, which is smaller compared to CH3NH3PbI3 (1.721 eV). In addition, we found that the optical absorption spectrum of the hybrid halide perovskite is red shifted with the reduction of the electronic band gap.

On the basis of ab initio calculation, we reported the structural and electronic properties of the nickel (Ni) substitution on the cobalt oxide (Co3O4) to produce nickel cobaltite (NiCo2O4) using generalized gradient approximation + U parameter (GGA + U) calculation method. The spinel NiCo2O4 with half-metallic behaviour has a relatively small band gap ∼0.64eV which is spotted decreased from pure Co3O4 band gap 1.26eV. This is due to nickel doping decreased the band gap which also implies that an increase in electrical conductivity. Owing to good electrical conductivity, NiCo2O4 thus enables to be considered for application in supercapacitor. Analysis of the partial density of states (PDOS) shows the differences contributions of cobalt (Co) at the tetrahedral site (Td) and Ni at the conduction bands: Co(Td) ions not affected the majority spin which is in contrast with Ni ions.

Structural, electronic and optical properties of nickel (Ni) doped bismuth selenide (Bi2Se3) in orthorhombic phase was studied via first principles approach using density functional theory (DFT). A generalized gradient approximation (GGA) for Perdew-Burke-Ernzerhof for solids (GGA-PBEsol) was employed as functional of exchange-correlation. The structural parameters of pure Bi2Se3 are in good agreement with the previous experimental and theoretical data. Calculated electronic properties of pure Bi2Se3 such as band gap is in agreement with the experiments. The effect of Ni has reduced the band gap of Bi2Se3 from 0.99 eV to 0.32 eV. Optical properties such as dielectric function was also calculated together with other optical properties and a comprehensive comparison was made. It was found that Ni-doping has contributed a better dielectric function, increased refractive index, and decreased extinction coefficient that provides many useful supports for technological applications. However, Ni-doping has caused slight deterioration of the absorption coefficient and the rise of a loss function.

The thin film of poly(methyl methacrylate) (PMMA) has been widely studied as host in a polymer electrolyte system due to its good mechanical stability towards lithium electrode. However, the brittle property of this film creates additional resistance for the ionic conduction. The addition of ionic liquid (IL) has been noticed to improve the brittleness of the film. In addition, its ionic conductivity can also be enhanced, but no free standing film can be obtained when higher amount of IL was added. Therefore, in this study, 1-methyl-3-pentamethyldisiloxymethylimidazolium bis(trifluoromethylsulfonyl)imide,[(SiOSi)C1C1im][NTf2], was incarcerated during free radical polymerization of MMA. Interestingly, this newly synthesized PMMA (PMMAIL) gives a flexible and transparent film with ionic conductivity of ∼10−7 S/cm at room temperature. The structural properties of this PMMAIL were further investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and optical microscope (OM).

In this study, first principles calculations based on density functional theory were used to evaluate optimized sructures and the total energy of the La doped PbTiO3 tetragonal (P4mm phase group). The calculations were conducted using local density approximation (LDA) functional as implemented in Cambridge Serial Total Energy Package (CASTEP) computer code. The different composition of Lanthanum (x) were doped on PbTiO3 resulting Pb1-xLaxTiO3 and its effect on the structural of Pb1-xLaxTiO3 were investigated. The different composition of La changed the lattice parameter and the volume of Pb1-xLaxTiO3. The total energy also were calculated and x= 0.2 is suitable composition of dapant to doped with PbTiO3 which is more stable compared with the other composition. The results are compared with experimental and other theoretical data.

In this paper, the effect of substitution of Co by d-valent elements such as Ag and Pt on electronic structure and magnetic properties of full Heusler type Co2FeSi alloys was investigated. Structural study reveals the presence of a small gap in the minority band structure around the vicinity of the Fermi level on Co2FeSi resulting to half-metallic behaviour. However, CoFeSiAg and CoFeSiPt cannot preserved the half-metalicity due to disappearing of the gap in the minority band structure due to the creation of new states around the Fermi level in the minority density of states. The variation in the magnetic moment of Co2FeSi with change of the atoms was attributed to the change in the local magnetic moment of atoms.

A new carbon material viz. graphene has been attracted an increasing research interest owing to its unique electrical and mechanical properties that is useful for the various device applications. The synthesis of graphene from graphene oxide usually involves harmful chemical reducing agents that are toxic and undesirable to human and the environment. By avoiding the use of toxic and environmentally harmful reductants, we report a green approach to effectively reduce graphene oxide to graphene in glucose solution at room temperature. Graphite oxide was synthesized from graphite powder using modified Hummers’ method. Graphite oxide then further exfoliated to graphene oxide by using ultrasonic irradiation. The mild reduction of graphene oxide is carried out by mixing graphene oxide solution with glucose. The reduction time is varied with 15, 30, 45 and 60 minutes. TEM images provide clear evidence for the formation of few layer graphene. Characterization of theresulting glucose reduced graphene oxide by FTIR indicates the partial removal of oxygen-containing functional groups from the surface of graphene oxide and formation of graphene with defects.

The effect of lithium intercalation on the structural and electronic properties of layered LiFeSO4OH and layered FeSO4OH cathode material is investigated using first-principle calculations. Results of Mulliken analysis, band gap, density of state, and charge density before and after intercalation are discussed. The importance of the strong covalent character of S–O and Fe–O bonds in high charge/discharge cycles and thermodynamic stabilities is confirmed. Analysis of the partial density of state reveals that the main contributor to the strong S–O covalent bond is the hybridization between the S 3s, S 3p electron state and the O 2p electron state. The Fe 3d orbital also plays an important role in cathode performance because it dominates the conduction and valence bands and radically changes upon the removal and insertion of lithium ion inside the cathode materials. The charge density elucidates the ionic and covalent characters of the bond inside the cathode.

Effect of glucose loading on the synthesis mesoporous carbon had been studied using hard template method where mesoporous silica SBA-15 was used as a template. To obtain a large pore of mesoporous carbon sample, a large pore of silica template was used. A series of mesoporous carbon sample was synthesized by loading different amounts of glucose (2.5g, 5.0g and 10.0g) as a carbon precursor to ensure that the template was fully impregnated with precursor. After treatment process, the surface area of carbon samples were measured with Brunauer-Emmett-Teller (BET) analysis and it shows that higher amount of glucose gives higher surface area due to the large pore of the template used. The samples then were tested with cyclic voltammetry technique at different scan rates (10, 20, 30 and 50 mVs-1) in 6M KOH electrolyte. It reveals that higher surface area samples show a higher specific capacitance with 119 F/g at slow scan rate 10 mVs-1.

In this study, gel polymer electrolytes (GPEs) system is prepared by the solution cast technique. The system consists of cellulose acetate (CA) as a host polymer, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as a dopant salt and diethylene glycol dibutylether (BDG) from glyme based family as a plasticizer. GPEs (65 wt. % CA–25 wt. % LiTFSI–10 wt. % BDG) sample is the highest conductivity of 2.88×10-3 S.cm−1 at room temperature. The lithium-electrolyte interfaced stability is established and the highest ionic conducting electrolyte is able to withstand up to 3.8V vs Li/Li+.

First-principles study based on density functional theory (DFT) framework for structural, electronic and optical properties of titanium dioxide (TiO2) in anatase and rutile phases are investigated. Anatase phase exhibits wide band gap compare to rutile phase. The partial and total density of states for TiO2 (anatase and rutile) describes the occupying of titanium (Ti) and oxygen (O) atoms at each energy level. TiO2 has a high dielectric constant to avoid the recombination process while its high refractive index provides the efficient of light diffusion. The optical absorption of TiO2 occurs in ultraviolet (UV) light of the wavelength photon. The results from the first-principles calculations will be helpful to give an understanding about the properties of TiO2 as promising photoanode in dye-sensitized solar cell (DSSC).

Gel polymer electrolyte films based on cellulose acetate (CA) complexed with ammonium iodide (NH4I), and ethylene carbonate (EC) was prepared by the solution cast technique. The conductivity increases to 10-4 Scm-1 upon the addition of salt. The incorporation of EC and to the salted polymer enhances the conductivity significantly 10-3 Scm-1. The complexation of doping materials with polymer was confirmed by X-ray diffraction and infrared studies. The present of ethylene carbonate (EC) as plasticizer did not disturbed the complexation between polymer and salt that has been confirm by FTIR. XRD studies further confirmed that all sample prepared are crystalline. This result affirmed that there were no complexations occur between plasticizer in the CA-NH4I polymer system.

The structural, electronic and optical properties of pure and neodymium (Nd) doped anatase titanium dioxide (TiO2)are investigated via first-principles calculations within density functional theory (DFT) approach. The band gap reduces to ~0.398 eV when Ti4+ is substituted with Nd3+ in TiO2 crystal structure. The presence of Nd 4f states in the conduction band of TiO2 clarifies the reducing of the band gap. The dielectric constant and refractive index of Nd-doped TiO2 increase compare to pure TiO2. Nd-doped TiO2 able to enhance light absorption to longer wavelength spectrum. The first-principles results obtained satisfy the criteria for Nd-doped TiO2 to become feasible photoanode material in dye-sensitized solar cell (DSSC) device.

Thermoelectric materials regain attention due to its capability as a solution of the environmental crisis. Bi2Te3 is one of the most efficient thermoelectric materials known that capable to operate at room temperature. A comprehensive analysis was conducted using density functional theory (DFT) that implemented in CASTEP to perform structural optimization. WIEN2K and BoltzTraP are used to calculate electronic and thermoelectric properties respectively. Local density approximation and spin–orbit coupling (SOC) were chosen within the calculation. SOC has developed multi-valleys band and increased degeneracy on band structure which indicates the increase of electrical and thermal conductivity. The occupancy of electrons also have increased. The SOC has increased the change rate of thermopower, electrical conductivity and thermal conductivity over temperature. However, SOC has decreased thermopower and overall performance of Bi2Te3. Nevertheless, the results are consistent with the other. SOC can be used to manipulate the properties of thermoelectric material for enhancement purpose.

The absorption rate of the photoanode can be influenced by the combination between the difference semiconductor quantum dot sensitizer. Six samples were prepared with difference weight percent (wt%) of ZnS from 0% to 50% and constant wt% of CdSe which then will be called as semiconductor QDs were immersed in 0.5mM of N719 dye. The purity of ZnS powder and CdSe powder was determined using x-ray diffraction (XRD).The ultraviolet-visible spectrophotometry (Uv-Vis) use to investigate the absorption spectrum and absorbance peak of this sample. 50 wt% of ZnS is the best composition to increase the absorbance peak of the photoanode. The Cyclic voltammetry (CV) of varying wt% of ZnS, found that the 40 wt% of ZnS is suitable combination for a DSSC’s photoanode and produced the higher current.

First-principles calculations on phase stability of three polymorphs of titanium dioxide (TiO2) in rutile, anatase and brookite phases are performed using density functional theory (DFT) and density functional theory plus Hubbard U (DFT+U) methods within generalized gradient approximation (GGA) for Perdew-Burke-Ernzerhof for solids (GGA-PBEsol) functional. The calculated cohesive energy with respect to the volume per formula unit of TiO2 is analyzed to evaluate the phase stability sequence for the TiO2 phases between rutile, anatase, and brookite. The results for the phase stability show good agreement with other theoretical reports. However, the difficult situation occurs for DFT in predicting correctly the phase stability of the rutile, anatase and brookite phases. Thus, the GGA-PBEsol+U for Ti 3d of TiO2 with U = 2, 4, 6 and 8eV are used to determine the effect of U on the phase stability. The DFT+U approach shows good agreement with the existing experimental data for the order of stability of TiO2 which give a good description of the phase stability of TiO2.

Acrylates such as poly (methyl methacrylate) (PMMA) has been widely studied as a polymer electrolyte film due to its good mechanical stability towards lithium electrode. However, commercial PMMAs even at high molecular weight were not able to produce a flexible film due to its polar nature that is prone to form interchain crosslinking via hydrogen bonding. Therefore, in this study, the opportunity of the PMMA chains to form hydrogen bondingwashinderedbyincarcerating1-methyl-3-pentamethyldisiloxymethylimidazolium bis(trifluoromethylsulfonyl) imide, [(SiOSi)C1C1im][NTf2] during the polymerization of MMA via free radical polymerization. Interestingly, this newly synthesized PMMA containing IL (PMMAIL) produced flexible and transparent films with higher thermal stability and lower glass transition temperature as compared to the neat PMMA. The structure confirmation of this PMMAIL was elucidated using Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared spectroscopy (FTIR). The thermal properties of this PMMAIL were investigated using Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC).

One of the fluorosulphate family cathode materials viz. LiFeSO4F is investigated by means of first principle calculation. The effects of lithium extraction on the electronic and structural properties in lithiated and delithiated phases were studied. It can be noted that the iono-covalency particularly in the M-X bond (M=transition metal, X= ligand) has played an important role to determine the redox potential instead of electronegativity. Therefore, the bond length (BL) and bond order (BO) are calculated to depict the ionic and covalent characters of the materials.

Methyl-grafted natural rubber (MG30) was treated with N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) to enhance it anti-aging properties. The treated MG30 was used as polymer electrolyte by incorporating lithium trifluoromethane sulfonate (LiTF) through solution-cast technique. The impedance behavior of the sample has been carried out by analyzing the dielectric permittivity, dissipation factor, dielectric modulus and ionic conductivity as a function of temperature at different frequencies through impedance spectroscopy. Keywords: Methyl-grafted natural rubber, polymer electrolyte, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, ionic conductivity, dielectric.

First-principles calculations based on the DFT approximated by GGA-PBEsol scheme has been utilized to predict the structural and electronic properties of Li2MnP2O7 and possible delithiated Li2-xMnP2O7 (x=1,2) configurations. Our results show that the approximation provided more reasonable predictions on the structural consistent with experiments. The calculated voltage profile underestimate the experimentally observed redox potential. Density of States (DOS) results reveals the insulator behavior of Li2MnP2O7.

In this work, solid polymer electrolyte compose of blended 30% poly (methyl methacrylate) grafted natural rubber (MG30)-poly (ethyl methacrylate) (PEMA) polymer blend doped with Lithium trimethasulfonate (LiCF3SO3) films were prepared by solution casting technique. . FTIR analysis showed that the interactions between lithium ions and oxygen atoms occur at the carbonyl functional group C=O where there is shifting in wavenumber from 1728 cm-1 of pure blend to lower wavenumber of blended MG30-PEMA on the MMA structure in both MG30 and PEMA. DSC analysis showed miscibility of polymer blend. From Electrochemical Impedance Spectrocopy analysis, ionic conductivity increase with the increasing of salt concentration. Maximum conductivity at room temperature is 9.20 x 10-6 Scm-1 was obtained when 30 wt% of LiCF3SO3 was added into the system. Ionic conductivity temperature dependence plots found obeys the Arrhenius rule.

We measured the resistivity and conductivity behavior of activated carbon and an activated carbon – graphene oxide (GO – AC) hybrid using two point probe method. As graphene oxide is well known as insulator, the effects of different ratio of activated carbon on conductivity of hybrid GO – AC was investigated.

Green composites of Glucose-reduced graphene oxide (GrGO) and manganese (IV) oxide (MnO2) were prepared in a typical chemical synthesis route assisted with ultrasonic irradiation. Conductivity studies conducted via 2-point probe method shows GrGO/MnO2(4:1) possessed electrical conductivity of 30.29 S cm-1with energy band gap of 8.47×10-1eV. The increase of D/G intensity ratio of GrGO with increase MnO2loading indicates more disorder carbon or defects are introduced from the reaction of carbon with MnO4-.

This article focuses on polymer-based gel electrolytes because basic features good self-standing characteristics, conductivity, and excellent window stability for supercapacitor devices when compared to aqueous electrolytes. Gel polymer electrolytes (GPEs) based on 30% poly (methyl methacrylate) grafted natural rubber (MG30) doped with ammonium triflate (NH4CF3SO3) and plasticized with ethylene carbonate (EC) were prepared by a solution casting method. Owing to being plasticized, the GPEs exhibit high room temperature ionic conductivity of 9.61×10−4 S.cm−1 at the composition of 26:14:60 wt% for MG30: NH4CF3SO3: EC. Linear sweep voltammogram study shows the highest conducting GPE exhibited electrochemical window stability of 2.7V. The GPEs has been employed to demonstrate the possibility of fabricating supercapacitor. Symmetric devices assembled using activated carbon as electrodes and GPEs (highest conducting) exhibit a specific capacitance of 32 F.g-1.

Polymer gel electrolytes based on cellulose acetate with lithium bis(oxalato)borate salt were prepared by dissolving in γ-butyrolactone solvent. The ionic conductivity and dielectric constant of the polymer gel electrolyte samples are investigated using electrochemical impedance spectroscopy over a frequency range from 100 Hz to 1 MHz. The ionic conductivity increased with increasing in the cellulose acetate concentration up to 2.4 wt.% (1.41 × 10−2 S cm−1) and thereafter decreased. The relationship between the dielectric constant and ionic conductivity has been interpreted. The optimum conducting polymer gel electrolyte shows electrochemical stability up to 4.7 V versus Li.

A series of mesoporous carbon sample was synthesized using silica template, SBA-15 with two different pore sizes. Impregnation method was applied using glucose as a precursor for converting it into carbon. An appropriate carbonization and silica removal process were carried out to produce a series of mesoporous carbon with different pore sizes and surface areas. Mesoporous carbon sample was then assembled as electrode and its performance was tested using cyclic voltammetry and impedance spectroscopy to study the effect of ion transportation into several pore sizes on electric double layer capacitor (EDLC) system. 6M KOH was used as electrolyte at various scan rates of 10, 20, 30 and 50 mVs−1. The results showed that the pore size of carbon increased as the pore size of template increased and the specific capacitance improved as the increasing of the pore size of carbon.

Organic thin film system consisting of Silicone-dammar (SD) polymer resin was prepared and studied with respect to their electrochemical properties. Dammar which is a local plant resin (Dipterocaupacea sp) was mixed with silicone in various compositions and the two components were modified by using a solvent. A thin film layered on glass slaid was obtained by Doctor Blade method and cured at room temperature. Silicone-dammar with a composition ratio of 80:20 (SD20) showed the highest non-wetting angle at 90.13 degrees however the sample with a composition ratio of 90:10 (SD10) showed the highest surface tension energy at 179.80 J in the contact angle test. Electrochemical Impedance Spectroscopy (EIS) analysis was done to investigate the electron transport and it was found that the SD10 sample provides a good medium for ionic mobility.

The epoxidized 30% PMMA grafted natural rubber (EMG30) was prepared using performic epoxidation method. 1HNMR studies confirm the appearance of epoxy group at 2.71 ppm in MG30 structure. The highest epoxidation content in EMG30 was used as a polymer host in gel polymer electrolyte (GPE) system. GPE film was prepared using 62.3 mol % EMG30, lithium trifluoromethanesulfonate (LiCF3SO3) and ethylene carbonate (EC). The conductivity of these polymer electrolytes was studied by AC impedance spectroscopy. The highest value was achieved up to 4.83 × 10−3 S cm−1 at 50 wt. % of EC in EMG30-LiCF3SO3 system. The increase in conductivity is associated to the increase of the segmental chain flexibility of the plasticized film indeed increases of the amorphous domain and was confirmed by X-ray diffraction (XRD) and differential scanning calorimetry (DSC) studies. These results show that this GPE system is a suitable candidate for use as an electrolyte in dye-sensitized polymer solar cell.