Arenst Andreas Arie; Joong Kee Lee
Abstract
In this work, LiCoO2(LCO) composite electrodes were coated by fullerene C60 thin film with different thickness of 60, 100 and 200 nm using a plasma thermal evaporation technique. The surface morphology of bare and coated samples was observed by scanning electron microscope (SEM). The electrochemical ...
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In this work, LiCoO2(LCO) composite electrodes were coated by fullerene C60 thin film with different thickness of 60, 100 and 200 nm using a plasma thermal evaporation technique. The surface morphology of bare and coated samples was observed by scanning electron microscope (SEM). The electrochemical characteristics of the coated electrodes as cathode materials in Lithium-Ion Batteries (LIB)were investigated by a galvanostatic charge-discharge test at various C-rates between 3.0 and 4.5 V and compared with those of uncoated samples. An improvement of the performances of the coated electrodes in terms of higher initial coulombic efficiency, higher capacity retention and better rate capability was shown by the 60 nm thick C60 coated LiCoO2 electrodes. It can be said that the thin C60 coating layer can minimize the dissolution of Co from the electrode to the electrolyte. As the thickness of coating layer was increased, the coated electrodes show a more severe capacity fade due to longer Li-ion diffusion path.
Arenst Andreas Arie; Vincent;Aditya Putranto; Vincent and Aditya Putranto
Abstract
Salacca peel was used to prepare activated carbon (AC) by chemical activation with potassium hydroxide (KOH). The activated carbon with the largest surface area and most developed porosity was then used in the batch adsorption experiments of methylene blue (MB). Activated carbons with a surface area ...
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Salacca peel was used to prepare activated carbon (AC) by chemical activation with potassium hydroxide (KOH). The activated carbon with the largest surface area and most developed porosity was then used in the batch adsorption experiments of methylene blue (MB). Activated carbons with a surface area of around 1939 m 2 /g were obtained. The adsorption equilibrium and kinetics of MB dyes from aquaeous solution on AC were also investigated. Adsorption isotherms of MB were correlated with the Langmuir, Freundich, Dubinin Radushkevich and Tempkin equations, and the heat of adsorption was determined. It was revealed that the Langmuir adsorption equation was more appropriate to represent the adsorption procedure of MB dyes compared to the other equations. Two simplified kinetic models including pseudo first- order and -second-order equations were used to evaluate the adsorption processes. The results indicated that the adsorption of MB dyes could be described properly by a pseudo-second-order equation. The kinetic parameters of this model were calculated and discussed.