Arenst Andreas Arie

Surface-Coated Silicon Anodes with Amorphous Carbon Film Prepared by Fullerene C60 Sputtering

Surface-coated silicon films with an amorphous carbon film are prepared by radio-frequency magnetron sputtering using the fullerene C 60 target. The carbon-coated silicon films are used as anode materials for lithium ion batteries and then investigated by the electrochemical measurements such as cyclic voltammetry and charge-discharge tests. Compared to the bare silicon anodes, the carbon-coated samples show more improvements in their electrochemical performances with a smaller irreversible capability in the first cycle and more stable cycle performance and maintain a high specific capacity of 2872 mAh g ―1 until the 50th cycle under a current density of 100 μA cm ―2 . It can be attributed to the presence of carbon film as an artificial passive layer to suppress the side reaction with the electrolyte. Additionally, the carbon layer can also provide a compressive stress, which may reduce the effect of a large volume change in silicon anodes during the charge-discharge tests, as indicated by the Raman spectroscopy recorded after the cycle tests.

A study of Li-ion diffusion kinetics in the fullerene-coated Si anodes of lithium ion batteries

The diffusion coefficient of lithium ions in fullerene-coated silicon thin film electrodes, prepared by the plasma-assisted deposition technique, was estimated by a specific electrochemical measurement known as cyclic voltammetry (CV) and then compared with that of a bare silicon film used as the anode in lithium ion batteries. Based on our experimental range, the diffusion coefficient of the fullerene-coated Si thin film was found to be ~10?9?cm2?s?1 or two orders of magnitude higher than that of the bare Si thin film (~1011?cm2?s?1). It can be concluded that the fullerene film acts as an artificial solid electrolyte interphase (SEI) layer during charging?discharging tests.

Electrochemical Properties of P-Doped Silicon Thin Film Anodes of Lithium Ion Batteries

Silicon would seem to be a possible candidate to replace graphite or carbon as anode materials for lithium ion batteries based on its potential high capacity of 4200 mAhg-1. The main problem that must be solved for commercial application of silicon as anode material was the poor cyclic performance due to severe volume expansion during repeated charged-discharged cycles and its low electrical conductivity. In this work, we proposed Phosphorus doped (P-doped) Si films as anodes in lithium ion batteries. The electrochemical properties of the silicon based electrodes were examined by means of charge-discharge and impedance test. In comparison with the bare silicon electrode, the P type silicon electrode exhibited higher specific capacity of 2585 mAhg-1 until the 50th cycle. It was attributed to the improved electrical conductivity of Si film and reduced charge transfer resistance

Preparation of Orange Peel Based Activated Carbons as Cathodes in Lithium Ion Capacitors

In this work, activated carbon was prepared from Indonesian local orange peel using ZnCl2 activation method at various chemical ratios. The structural and morphological characteristics of orange peel based activated carbons were investigated using scanning electron microscope (SEM), Brunaeuer-Emmett-Teller surface analyzer. The highest surface area was estimated as 1200 m2g-1, obtained by the mass ratio of 1:2 (biomass : ZnCl2). The obtained carbon samples were then tested as cathodes in Lithium Ion Capacitors. Electrochemical measurement was examined by half cell configuration, using 1 M LiPF6 in EC/EMC/DMC solution (1:1:1 v/v) as electrolyte and Li metal as reference electrode. From cyclic voltammetry (CV) test, it was shown that orange peel based activated carbon demonstrated a stable electrochemical characteristics, with specific capacitance of 56 Fg-1 measured at scan rate of 1 mVs-1 under cut-off voltages between 2.5 and 4 V.

Synthesis of Boron-Doped C60 Film Using Plasma-Assisted Thermal Evaporation Technique and its Electrochemical Characterizations

Boron doped C60 (B:C60) thin films were synthesized by a plasma-assisted thermal evaporation system. Scanning electron microscope (SEM), Raman spectroscopy, Fourier transform infra red (FTIR) and X-ray photo electron spectroscopy (XPS) were used to investigate the morphology and structural characteristics of the films, respectively. The electrochemical characterization of B:C60 films was then introduced as a coating layer for silicon film anodes in a lithium ion battery. Typical electrochemical measurements such as cyclic voltammetry (CV) and impedance spectroscopy were used to characterize the B:C60 coated silicon electrodes. CV profiles implied that B:C60 coating layer could act as a passive layer with respect to the insertion and extraction of lithium ions into the silicon film electrode. Moreover, impedance results showed that the coating layer contributed to the smaller charge transfer resistance at the electrode/electrolyte interface.

Estimation of Li-Ion Diffusion Coefficients in C60 Coated Si Thin Film Anodes Using Electrochemical Techniques

C60 coated Si thin films were prepared sequentially by a plasma enhanced chemical vapor deposition and a plasma assisted thermal evaporation technique. The films were then utilized as anode materials for lithium ion batteries. The diffusion coefficients of Li-ions in the film electrodes were then estimated by typical electrochemical techniques such as cyclic voltammetry and electrochemical impedance spectroscopy. The diffusion coefficients determined by both methods were found to be consistent each other. The diffusion coefficient of coated samples was obviously higher than that of bare silicon thin films, indicated that the kinetic properties of lithium ion transport in silicon film electrodes were enhanced by the C60 film coating on its surface.

Preparation of Boron Doped Fullerene Film by a Thermal Evaporation Technique using Argon Plasma Treatment and Its Electrochemical Application

Boron doped fullerene C60 (B:C60) films were prepared by the thermal evaporation of C60 powder using argon plasma treatment. The morphology and structural characteristics of the thin films were investigated by scanning electron microscope (SEM), Fourier transform infra-red spectroscopy (FTIR) and x-ray photo electron spectroscopy (XPS). The electrochemical application of the boron doped fullerene film as a coating layer for silicon anodes in lithium ion batteries was also investigated. Cyclic voltammetry (CV) measurements were applied to the B:C60 coated silicon electrodes at a scan rate of 0.05 mVs-1. The CV results show that the B:C60 coating layer act as a passivation layer with respect to the insertion and extraction of lithium ions into the silicon film electrode.

Adsorption of Cu (II) from Aqueous Solution by Salacca Peel Based Activated Carbons

In n 687.67 mg Cu(II)/g activated carbon. The kinetic study showed that the copper adsorption on the SPAC followed the pseudo-second order model. The results of this study indicated that SPAC was an effective adsorbent for removing copper ions from aqueous solutions.

The effect of activated carbon support surface modification on characteristics of carbon nanospheres prepared by deposition precipitation of Fe-catalyst

In this study the effect of activated carbon support modification to synthesis of CNSs was observed. Modification of activated carbon was done by using nitric acid. The effect of modification was analyzed from its FTIR spectra. The Fe catalysts were deposited on to the support by using urea deposition precipitation method at various initial catalysts concentration. CNSs was synthesized by utilizing cooking palm oil as renewable carbon source, and pyrolized at 700°C for 1 hour under nitrogen atmosphere. The products obtained then analyzed using SEM-EDS, TEM, XRD, and Raman spectroscopy. The modification of activated carbon support had increased the oxygen functional group. This increase resulted on increase of metal catalysts deposited on activated carbon surface. Peak of C (100) was observed, while ID/IG of samples were obtained around 0.9, which is commonly obtained for CNSs. High catalysts loading on modified activated carbon support caused decomposition of CNSs and formation carbon onion.

Structural and preliminary electrochemical characteristics of palm oil based carbon nanospheres as anode materials in lithium ion batteries

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