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New Analysis of Electrochemical Impedance Spectroscopy for Lithium-ion Batteries
Osaka, Tetsuya,Nara, Hiroki,Mukoyama, Daikichi,Yokoshima, Tokihiko The Korean Electrochemical Society 2013 Journal of electrochemical science and technology Vol.4 No.4
First of all, we express our deepest sympathies for the passing of Professor Su-Moon Park. In the present paper, an electrochemical impedance spectroscopy (EIS), which Professor Su-Moon Park also used frequently for the investigation of electroconducting polymer, is introduced as a recent evaluation tool for a commercially available lithium-ion battery (LIB). The paper surveys how to design equivalent circuits while explaining physical and chemical phenomena in the LIB and how to get more accurate impedance spectra with varying the measuring temperatures. Additionally, a square current EIS (SC-EIS) technique, which we have suggested, is introduced for the larger LIB system as a promising technique for the future.
Electrochemical Behavier of Li4Ti5O12/CNT Composite for Energy Storage
김홍일,양정진,김한주,Tetsuya Osaka,박수길 한국전기화학회 2010 한국전기화학회지 Vol.13 No.4
The Li4Ti5O12/CNT composite is prepared by ultrasound associated sol-gel method. The prepared composite is characterized by SEM, TEM, XRD and TG analysis, and their electrochemical behaviors are investigated by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge test in 1M LiBF4/PC electrolyte. From the results, it is identified that the Li4Ti5O12 nanoparticles coated on CNT surface have regular size with around 10~30 nm and spinel-framework structure. At the current rate of 20C, the discharge capacities of Li4Ti5O12/CNT composites with CNT contents of 15, 30 and 50 wt% are 57, 63 and 48mAhg−1, respectively,which have similar value. The improved electrochemical behavior of the Li4Ti5O12/CNT composite
Kim, Han-Joo,Osaka, Tetsuya,Park, Soo-Gil 한국공업화학회 2005 응용화학 Vol.9 No.1
Lithium titanium oxide as anode material for energy storage prepared by novel synthesis method. Li₄Ti_5O_12 based spinel-framework structures are of great interest material for lithium-ion batteries. We describe here the first synthesis of nano-scale Li₄Ti_5O_12 using sol-gel method. According to the X-ray diffraction and scanning electron microscopy analysis, uniformly distributed Li₄Ti_5O_12 particles with grain sizes of 100nm were synthesized. Lithium cells, consisting of Li₄Ti_5S_12 anode and lithium cathode showed the 173mAh/g in the range of 1.0 ~2.5V . Furthermore, the crystalline structure of Li₄Ti_5O_12 didn't transform during the lithium intercalation and deintercalation process.
Togasaki, Norihiro,Yokoshima, Tokihiko,Oguma, Yasumasa,Osaka, Tetsuya The Korean Electrochemical Society 2021 Journal of electrochemical science and technology Vol.12 No.4
For a battery module where single cells are connected in series, the single cells should each have a similar state of charge (SOC) to prevent them from being exposed to an overcharge or over-discharge during charge-discharge cycling. To detect the existence of unbalanced SOC cells in a battery module, we propose a simple measurement method using a single-frequency response of electrochemical impedance spectroscopy (EIS). For a commercially available graphite/nickel-cobalt-aluminum-oxide lithium-ion cell, the cell impedance increases significantly below SOC20%, while the impedance in the medium SOC region (SOC20%-SOC80%) remains low with only minor changes. This impedance behavior is mostly due to the elementary processes of cathode reactions in the cell. Among the impedance values (Z, Z', Z"), the imaginary component of Z" regarding cathode reactions changes heavily as a function of SOC, in particular, when the EIS measurement is performed around 0.1 Hz. Thanks to the significant difference in the time constant of cathode reactions between ≤SOC10% and ≥SOC20%, a single-frequency EIS measurement enlarges the difference in impedance between balanced and unbalanced cells in the module and facilitates an ~80% improvement in the detection signal compared to results with conventional EIS measurements.
Agostini, Marco,Hassoun, Jusef,Liu, Jun,Jeong, Moongook,Nara, Hiroki,Momma, Toshiyuki,Osaka, Tetsuya,Sun, Yang-Kook,Scrosati, Bruno American Chemical Society 2014 ACS APPLIED MATERIALS & INTERFACES Vol.6 No.14
<P>In this paper, we report a lithium-ion battery employing a lithium sulfide cathode and a silicon-based anode. The high capacity of the silicon anode and the high efficiency and cycling rate of the lithium sulfide cathode allowed optimal full cell balance. We show in fact that the battery operates with a very stable capacity of about 280 mAh g<SUP>–1</SUP> at an average voltage of 1.4 V. To the best of our knowledge, this battery is one of the rare examples of lithium-metal-free sulfur battery. Considering the high theoretical capacity of the employed electrodes, we believe that the battery here reported may be of potential interest as high-energy, safe, and low-cost power source for electric vehicles.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2014/aamick.2014.6.issue-14/am4057166/production/images/medium/am-2013-057166_0007.gif'></P>
Shanmugam, Sangaraju,Sivanantham, Arumugam,Matsunaga, Mariko,Simon, Ulrich,Osaka, Tetsuya Elsevier 2019 ELECTROCHIMICA ACTA Vol.297 No.-
<P><B>Abstract</B></P> <P>We describe a facile and simple solid-state thermolysis route for the preparation of Co, Ni, and Fe phosphide nanoparticles embedded in amorphous carbon using an organometallic complex. This was achieved by using a suitable organometallic complex in a single step synthetic route without using any solvent or catalyst. The advantage of using such precursor was to offer a source for metal, phosphorus and carbon without using any additional sources. The morphology of products was characterized by transmission electron microscopy, scanning electron microscopy and nature of carbon was analyzed using the Raman microscope and X-ray diffraction. The electrocatalytic oxygen evolution reaction (OER) activity and stability of the metal phosphide nanostructure was evaluated using the rotating disk electrode technique. The CoP, NiP and FeP exhibit the OER overpotential of 370, 380 and 550 mV at 10 mA cm<SUP>−2</SUP>, respectively in 0.1 M KOH electrolyte. Among prepared phosphide catalysts, cobalt phosphide shows a lowest Tafel slope indicate favorable kinetics for the OER activity than nickel and iron phosphide catalysts.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Kim, Hong-Il,Yang, Jeong-Jin,Kim, Han-Joo,Osaka, Tetsuya,Park, Soo-Gil The Korean Electrochemical Society 2010 한국전기화학회지 Vol.13 No.4
The $Li_4Ti_5O_{12}$/CNT composite is prepared by ultrasound associated sol-gel method. The prepared composite is characterized by SEM, TEM, XRD and TG analysis, and their electrochemical behaviors are investigated by cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge test in 1M $LiBF_4$/PC electrolyte. From the results, it is identified that the $Li_4Ti_5O_{12}$ nanoparticles coated on CNT surface have regular size with around 10~30 nm and spinel-framework structure. At the current rate of 20C, the discharge capacities of $Li_4Ti_5O_{12}$/CNT composites with CNT contents of 15, 30 and 50 wt% are 57, 63 and $48mAhg^{-1}$, respectively, which have similar value. The improved electrochemical behavior of the $Li_4Ti_5O_{12}$/CNT composite electrode is attributed to the addition of CNT with electronic conductivity.