Structural and electrochemical evaluation of bismuth doped lithium titanium oxides for lithium ion batteries

Subburaj, T.,Prasanna, K.,Kim, Ki Jae,Ilango, P. Robert,Jo, Yong Nam,Lee, Chang Woo Elsevier 2015 Journal of Power Sources Vol.280 No.-

<P><B>Abstract</B></P> <P>Micro-sized Li<SUB>4</SUB>Ti<SUB>5−x</SUB>Bi<SUB>x</SUB>O<SUB>12</SUB> (0 ≤ x ≤ 0.15) materials are synthesized using a simple solid state method in air. The structural, morphological, and electrochemical characteristics of Bi-doped lithium titanates and pristine samples are methodically analyzed by X-ray diffraction (XRD), Raman spectroscopy, field emission-scanning electron microscopy (FE-SEM), and electrochemical impedance spectroscopy (EIS). The XRD and Raman spectroscopy results demonstrate that bismuth-doping do not alter the spinel structure and good crystalline materials are synthesized. The FE-SEM images show that all samples possess the same morphological characteristics, with a particle size distribution of 0.5–1 μm. The electrochemical cycling testing reveals that the Li<SUB>4</SUB>Ti<SUB>4.9</SUB>Bi<SUB>0.10</SUB>O<SUB>12</SUB> sample exhibits discharge capacities of 205.4 mAh g<SUP>−1</SUP>, 160.8 mAh g<SUP>−1</SUP>, and 135.4 mAh g<SUP>−1</SUP> after 50 cycles at 1C, 5C, and 10C-rates, respectively. The differential capacity curves suggest that the Li<SUB>4</SUB>Ti<SUB>4.9</SUB>Bi<SUB>0.10</SUB>O<SUB>12</SUB> sample has a weaker polarization effect than the other samples. The EIS measurements imply that the Li<SUB>4</SUB>Ti<SUB>4.9</SUB>Bi<SUB>0.10</SUB>O<SUB>12</SUB> sample possesses a high electronic conductivity and lithium ion diffusivity, which demonstrate that this new Li<SUB>4</SUB>Ti<SUB>4.9</SUB>Bi<SUB>0.10</SUB>O<SUB>12</SUB> material would be a good candidate as an anode for lithium ion batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bi-doped Li<SUB>4</SUB>Ti<SUB>5</SUB>O<SUB>12</SUB> anode materials are synthesized by facile solid-state method. </LI> <LI> Bi-doping leads to give high electronic conductivity and lithium diffusivity. </LI> <LI> Also, it is effective to be in stable structure and suppression of polarization effect. </LI> <LI> Li<SUB>4</SUB>Ti<SUB>4.9</SUB>Bi<SUB>0.10</SUB>O<SUB>12</SUB> material would be a good candidate as an anode for lithium ion batteries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Physical and electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O₂ cathodes coated by Sb₂O₃ using a sol–gel process

Ilango, P. Robert,Subburaj, T.,Prasanna, K.,Jo, Yong Nam,Lee, Chang Woo Elsevier 2015 Materials chemistry and physics Vol.158 No.-

<P><B>Abstract</B></P> <P>Sb<SUB>2</SUB>O<SUB>3</SUB>-coated LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> cathode materials have been prepared using a sol–gel process. The surface-coated cathode materials have been physically characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and field emission transmission electron microscopy (FE-TEM). The electrochemical characteristics have been investigated by electrochemical impedance spectroscopy (EIS), galvanostatic cycler, and cyclic voltammetry (CV). Moreover, the Sb<SUB>2</SUB>O<SUB>3</SUB> coating does not affect the crystal structure of LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> but instead form a thin compact layer on the surface. The 1wt% of Sb<SUB>2</SUB>O<SUB>3</SUB>-coated LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> cathode coated shows stable cyclability with capacity retention of 98% after the 30 cycles, which is higher than the bare and 2 wt% Sb<SUB>2</SUB>O<SUB>3</SUB>-coated cathodes and the EIS and CV tests illustrate the suppressed charge transfer resistance and good reversibility for the optimized coating concentration on the cathode.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We successfully prepared Sb<SUB>2</SUB>O<SUB>3</SUB>-coated LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> cathodes by a sol–gel process. </LI> <LI> Sb<SUB>2</SUB>O<SUB>3</SUB> has been used as an additive to give a protection layer from HF attack. </LI> <LI> Electrochemical performance of 1 wt% Sb<SUB>2</SUB>O<SUB>3</SUB>-coated LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> was superior. </LI> <LI> 1 wt% Sb<SUB>2</SUB>O<SUB>3</SUB>-coated LiNi<SUB>1/3</SUB>Co<SUB>1/3</SUB>Mn<SUB>1/3</SUB>O<SUB>2</SUB> cathodes reveal good cyclability at high rates. </LI> </UL> </P>

Elucidation of cube-like red iron oxide @ carbon nanofiber composite as an anode material for high performance lithium-ion storage

P. Santhoshkumar,T. Subburaj,K. Karuppasamy,A. Kathalingam,Dhanasekaran Vikraman,박현창,김현석 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-

Herein, a red iron oxide @ carbon fiber (RIO@CF) composite is prepared via a simple and effective singlehydrothermal and calcination process. The physico-chemical characteristics of as-prepared electrodeactive materials are examined by X-ray photoelectron spectroscopy, high resolution field emissionscanningelectron microscopy and field emission-tunneling electron microscopy analyses. When usedas the anode material in the Li-ion battery, as-prepared RIO@CF composite have shown a specific capacityof 1138 mAh g 1 after 150 cycles with a capacity retention of 86% at a current density of 100 mA g 1. Moreover, a specific capacity of 825 mAh g 1 is achieved in the first cycle at a current density of about5000 mA g 1. Thus, when compared to the pristine nano-cube-like red iron oxide (RIO) electrode material,the RIO@CF composite electrode exhibits an outstanding cyclic stability and rate capacity. This electrochemicalenhancement facilitates effective lithium ion transport into the RIO@CF composite electrode,thus improving the electrical conductivity. In addition, the application of a homogeneous carbon fibercoating can provide effective contact between the electrode surface and the electrolyte to further benefitthe electrochemical performance.

A Ripple Rejection Inherited RPWM for VSI Working with Fluctuating DC Link Voltage

Jarin, T.,Subburaj, P.,Bright, Shibu J V The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.5

A two stage ac drive configuration consisting of a single-phase line commutated rectifier and a three-phase voltage source inverter (VSI) is very common in low and medium power applications. The deterministic pulse width modulation (PWM) methods like sinusoidal PWM (SPWM) could not be considered as an ideal choice for modern drives since they result mechanical vibration and acoustic noise, and limit the application scope. This is due to the incapability of the deterministic PWM strategies in sprawling the harmonic power. The random PWM (RPWM) approaches could solve this issue by creating continuous harmonic profile instead of discrete clusters of dominant harmonics. Insufficient filtering at dc link results in the amplitude distortion of the input dc voltage to the VSI and has the most significant impact on the spectral errors (difference between theoretical and practical spectra). It is obvious that the sprawling effect of RPWM undoubtedly influenced by input fluctuation and the discrete harmonic clusters may reappear. The influence of dc link fluctuation on harmonics and their spreading effect in the VSI remains invalidated. A case study is done with four different filter capacitor values in this paper and results are compared with the constant dc input operation. This paper also proposes an ingenious RPWM, a ripple dosed sinusoidal reference-random carrier PWM (RDSRRCPWM), which has the innate capacity of suppressing the effect of input fluctuation in the output than the other modern PWM methods. MATLAB based simulation study reveals the fundamental component, total harmonic distortion (THD) and harmonic spread factor (HSF) for various modulation indices. The non-ideal dc link is managed well with the developed RDSRRCPWM applied to the VSI and tested in a proto type VSI using the field programmable gate array (FPGA).

A Ripple Rejection Inherited RPWM for VSI Working with Fluctuating DC Link Voltage

T. Jarin,P. Subburaj,Shibu J V Bright 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.5

A two stage ac drive configuration consisting of a single-phase line commutated rectifier and a three-phase voltage source inverter (VSI) is very common in low and medium power applications. The deterministic pulse width modulation (PWM) methods like sinusoidal PWM (SPWM) could not be considered as an ideal choice for modern drives since they result mechanical vibration and acoustic noise, and limit the application scope. This is due to the incapability of the deterministic PWM strategies in sprawling the harmonic power. The random PWM (RPWM) approaches could solve this issue by creating continuous harmonic profile instead of discrete clusters of dominant harmonics. Insufficient filtering at dc link results in the amplitude distortion of the input dc voltage to the VSI and has the most significant impact on the spectral errors (difference between theoretical and practical spectra). It is obvious that the sprawling effect of RPWM undoubtedly influenced by input fluctuation and the discrete harmonic clusters may reappear. The influence of dc link fluctuation on harmonics and their spreading effect in the VSI remains invalidated. A case study is done with four different filter capacitor values in this paper and results are compared with the constant dc input operation. This paper also proposes an ingenious RPWM, a ripple dosed sinusoidal referencerandom carrier PWM (RDSRRCPWM), which has the innate capacity of suppressing the effect of input fluctuation in the output than the other modern PWM methods. MATLAB based simulation study reveals the fundamental component, total harmonic distortion (THD) and harmonic spread factor (HSF) for various modulation indices. The non-ideal dc link is managed well with the developed RDSRRCPWM applied to the VSI and tested in a proto type VSI using the field programmable gate array (FPGA).

Partial Discharge Signal Denoising using Adaptive Translation Invariant Wavelet Transform-Online Measurement

Maheswari, R.V.,Subburaj, P.,Vigneshwaran, B.,Iruthayarajan, M. Willjuice The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

Partial discharge (PD) measurements have emerged as a dominant investigative tool for condition monitoring of insulation in high voltage equipment. But the major problem behind them the PD signal is severely polluted by several noises like White noise, Random noise, Discrete Spectral Interferences (DSI) and the challenge lies with removing these noise from the onsite PD data effectively which leads to preserving the signal for feature extraction. Accordingly the paper is mainly classified into two parts. In first part the PD signal is artificially simulated and mixed with white noise. In second part the PD is measured then it is subjected to the proposed denoising techniques namely Translation Invariant Wavelet Transform (TIWT). The proposed TIWT method remains the edge of the original signal efficiently. Additionally TIWT based denoising is used to suppress Pseudo Gibbs phenomenon. In this paper an attempt has been made to review the methodology of denoising the PD signals and shows that the proposed denoising method results are better when compared to other wavelet-based approaches like Fast Fourier Transform (FFT), Discrete Wavelet Transform (DWT), by evaluating five different parameters like, Signal to noise ratio, Cross-correlation coefficient, Pulse amplitude distortion, Mean square error, Reduction in noise level.

Partial Discharge Signal Denoising using Adaptive Translation Invariant Wavelet Transform-Online Measurement

R.V. Maheswari,P. Subburaj,B. Vigneshwaran,M. Willjuice Iruthayarajan 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.2

Partial discharge (PD) measurements have emerged as a dominant investigative tool for condition monitoring of insulation in high voltage equipment. But the major problem behind them the PD signal is severely polluted by several noises like White noise, Random noise, Discrete Spectral Interferences (DSI) and the challenge lies with removing these noise from the onsite PD data effectively which leads to preserving the signal for feature extraction. Accordingly the paper is mainly classified into two parts. In first part the PD signal is artificially simulated and mixed with white noise. In second part the PD is measured then it is subjected to the proposed denoising techniques namely Translation Invariant Wavelet Transform (TIWT). The proposed TIWT method remains the edge of the original signal efficiently. Additionally TIWT based denoising is used to suppress Pseudo Gibbs phenomenon. In this paper an attempt has been made to review the methodology of denoising the PD signals and shows that the proposed denoising method results are better when compared to other wavelet-based approaches like Fast Fourier Transform (FFT), Discrete Wavelet Transform (DWT), by evaluating five different parameters like, Signal to noise ratio, Cross-correlation coefficient, Pulse amplitude distortion, Mean square error, Reduction in noise level.