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Effect of Lithia and Substrate on the Electrochemical Performance of a Lithia/Cobalt Oxide Composite Thin‐Film Anode
Author(s) -
Yu Yan,
Shi Yi,
Chen ChunHua
Publication year - 2006
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200600157
Subject(s) - faraday efficiency , materials science , foil method , scanning electron microscope , anode , substrate (aquarium) , thin film , cobalt oxide , electrochemistry , electrode , analytical chemistry (journal) , dielectric spectroscopy , chemical engineering , composite number , x ray photoelectron spectroscopy , oxide , composite material , metallurgy , nanotechnology , chemistry , chromatography , engineering , oceanography , geology
Abstract Highly porous reticular Li 2 O/CoO composite thin films fabricated by electrostatic spray deposition were investigated by using X‐ray diffraction, scanning electron microscopy, galvanostatic cell‐cycling measurements, and AC impedance spectroscopy measurements. The results of the electrochemical tests indicate that the initial coulombic efficiency and capacity retention are dependent on Li 2 O content and the specific surface area of the deposited layer. Irrespective of the type of substrate, the electrode gave the best electrochemical performance when the molar ratio of Li to Co was controlled at 1:1. At the optimal composition, at 0.2 C the initial coulombic efficiency was as high as 81.9 % and 83.6 % for the film on Cu foil and on porous Ni, respectively. The Li 2 O/CoO (Li/Co=1:1) films on Ni foam and Cu foil had sustained capacities of up to 790 and 715 mAh g −1 , respectively, at a rate of 1 C over 100 cycles at 25 °C. Similar cycling experiments carried out at 70 °C showed that the capacity is temperature‐sensitive, and it exhibited reversible capacities as high as 1018 (Cu foil) and 1269 mAh g −1 (Ni foam) for up to 100 cycles. The thin‐film electrodes on Ni foam always performed better than those on Cu foil. Cycling at elevated temperature (70 °C) also resulted in a significant increase in capacity.