Room Temperature Ionic Liquid as Electrolyte for Lithium Ion Battery

Symposium: Physical and Analytical Electrochemistry: no. I3, Molten Salts and Ionic Liquids 18published_or_final_version222nd Meeting of Electrochemical Society and Pacific Rim Meeting of Related Societies on Electrochemical and Solid-State Science (PRiME 2012), Honolulu, Hawaii, USA, 7-12 October 2012. In Electrochemical Society Meeting Abstracts, v. MA2012-02, abstract no. 372

Negative electrode for lithium battery in room temperature molten salt

Abstract no. 1386published_or_final_versio

Electrodeposited tin coating as negative electrode material for lithium-ion battery in room temperature molten salt

A new room temperature molten salt (RTMS) [1-methyl-3-ethylimidazolium/AlCl3/SnCl2 (3:2:0.5)] was developed for depositing tin on a copper electrode. Different tin crystallites were deposited at different temperatures, giving widely different performances of the assembled lithium cell [Sn (Cu)/LiCl buffered MEICl-AlCl3 RTMS/lithium]. Tin film deposited at 50°C or higher gave a more desirable crystal structure and an improved performance than films obtained at lower temperatures. Both cyclic voltammetry and galvanostatic cycling show the formation of three major lithium-tin alloy phases corresponding to the phase transition of LiSn/Li7Sn3, Li13Sn5/Li7Sn2, and Li7Sn2/Li22Sn5. Increases in the charging and discharging capacities were found with the deposition of higher lithium-rich tin alloys, though at the degradation of the irreversible capacity at the first cycle. The discharging capacity decreased rapidly, producing loose, expanded, and irregular crystallites upon cycling at a high current density (cd) (1.0 mA/cm2). However, an average capacity of 140 mAh/g, coulombic efficiency around 85%, and more than 200 cycles were obtained at a low cd (0.4 mA/cm2). The improvement is attributed to the deposition of small and regular tin crystallites that allows reversible insertion and removal of lithium from a more stable crystal structure without a significant volume change during cycling.published_or_final_versio

LiTFSI-based room temperature ionic liquids for high energy secondary lithium ion battery

Symposium 4 - Electrochemical Energy Conversion and Storage: Advances in Battery ResearchpostprintThe 61th Annual Meeting of the International Society of Electrochemistry: Electrochemistry from Biology to Physics, Nice, France, 26 September-1 October 2010

Asymptotic properties of order statistics correlation coefficient in the normal cases

We have previously proposed a novel order statistics correlation coefficient (OSCC), which possesses some desirable advantages when measuring linear and monotone nonlinear associations between two signals. However, the understanding of this new coefficient is far from complete. A lot of theoretical questions, such as the expressions of its distribution and moments, remain to be addressed. Motivated by this unsatisfactory situation, in this paper we prove that for samples drawn from bivariate normal populations, the distribution of OSCC is asymptotically equivalent to that of the Pearson's product moment correlation coefficient (PPMCC). We also reveal its close relationships with the other two coefficients, namely, Gini correlation (GC) and Spearman's rho (SR). Monte Carlo simulation results agree with the theoretical findings. © 2008 IEEE.published_or_final_versio

Gene selection in microarray data analysis for brain cancer classification

Cancer classification has been one of the most challenging tasks in clinical diagnosis. At present cancer classification is done mainly by looking through the cells' morphological differences, which do not always give a clear distinction of cancer subtypes. Unfortunately, this may have a significant impact on the final outcome of whether a patient could be cured effectively. Microarray technology can play an important role on diagnosing which type of disease one is carrying. The gene selection process is critical for developing gene markers for faster and more accurate diagnosis. In this paper, we develop a method using pairwise data comparisons instead of the one-over-the-rest approach used nowadays. Results are evaluated using available clustering techniques including hierarchical clustering and k-means clustering. Using pairwise comparison, the best accuracy achieved is 95% while it is only 83% when using one-over-the-rest approach. ©2006 IEEE.published_or_final_versio

Order statistic correlation coefficient and its application to association measurement of biosignals

In this paper we propose a novel and fast nonlinear association measure based on order statistics and rearrangement inequality. We employ one episode of heart signal, one episode of EEG signal and 1000 white Gaussian noises in our study. Extensive statistical analysis are performed based on one linear model and one nonlinear model. Comparative studies with three other prominent methods are presented. Theoretical derivations and experimental results suggest that our new method has small biasedness, high sensitivity to changes in association, fast computational speed, and robustness under monotone nonlinear transformations. © 2006 IEEE.published_or_final_versio

Order statistics correlation coefficient as a novel association measurement with applications to biosignal analysis

In this paper, we propose a novel correlation coefficient based on order statistics and rearrangement inequality. The proposed coefficient represents a compromise between the Pearson's linear coefficient and the two rank-based coefficients, namely Spearman's rho and Kendall's tau. Theoretical derivations show that our coefficient possesses the same basic properties as the three classical coefficients. Experimental studies based on four models and six biosignals show that our coefficient performs better than the two rank-based coefficients when measuring linear associations; whereas it is well able to detect monotone nonlinear associations like the two rank-based coefficients. Extensive statistical analyses also suggest that our new coefficient has superior anti-noise robustness, small biasedness, high sensitivity to changes in association, accurate time-delay detection ability, fast computational speed, and robustness under monotone nonlinear transformations. © 2007 IEEE.published_or_final_versio

Blind spectra decomposition of MRSI of the brain with tumor by sparse component analysis

Magnetic Resonance Spectroscopy Imaging (MRSI) is suitable for analyzing brain tumor metabolites in vivo. Several tissue types may exist in the tumor lesion area, and thus the measured MR spectra are a linear superposition of the constituent spectra of each of the different tissues. In this abstract we describe a novel approach, based on sparse component analysis, to recover the constituent spectra from the measured mixtures. The method is applied to experimental MRSI data of a brain with tumor lesion, and promising result is obtained. Compared to the existing BSD and cNMF approaches, this method is relatively simple and very fast.published_or_final_versio

Study on electrochemical properties of FeS2 in room temperature molten salt

In this paper, FeS2 electrodes have been prepared by using reactive codeposition methods. The electrochemical performances of FeS2 were studied in LiCl buffer Lewis neutral 1-methyl-3-ethylimidazolium chloride (MeEtImCl)/AlCl3 (room temperature molten salt) melts. The results show that FeS2 electrodes possess reversible Li ion intercalation and deintercalation behavior in the first step two electron processes.published_or_final_versio