Materials
·
2021
·Vol. 14
·期 13
·3624
·
IF 3.623
Zhijie Xu,Fangxu Hu,De Li,Yong Chen
In the late 1960s, the establishment of Prigogine’s dissipative structure theory laid the foundation for the (electro)chemical oscillation phenomenon, which has been widely investigated in some electrochemical reactions, such as electro-catalysis and electro-deposition, while the electrochemical oscillation of Li-ion batteries has just been discovered in spinel Li4Ti5O12a few years before. In this work, spinel LiCrTiO4samples were synthesized by using a high-temperature solid-state method, characterized with SEM (Scanning electron microscope), XRD (X-ray diffraction), Raman and XPS (X-ray photoelectron spectroscopy) measurements, and electrochemically tested in Li-ion batteries to study the electrochemical oscillation. When sintering in a powder form at a temperature between 800 and 900 °C, we achieved the electrochemical oscillation of spinel LiCrTiO4during charging, and it is suppressed in the non-stoichiometric LiCrTiO4samples, especially for reducing the Li content or increasing the Cr content. Therefore, this work developed another two-phase material as the powder-sintered LiCrTiO4exhibiting the electrochemical oscillation in Li-ion batteries, which would inspire us to explore more two-phase electrode materials in Li-ion batteries, Na-ion batteries, etc.Keywords:Li-ion battery;LiCrTiO4;electrochemical oscillation;phase transition;spinel structure
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
PubMed
高影响因子
Journal of Physical Chemistry C
·
2021
·
IF 4.126
Tu Lan,Qian Qiao,Fangxu Hu,De Li,Yong Chen
The electrochemical signals are very important to analyze and regulate the electrochemical systems, and the electrochemical oscillation is a newly discovered electrochemical signal in Li-ion batteries (LIBs), including the voltage and current oscillations. In this work, the Li4Ti5O12 was prepared using a home-made spray-drying instrument and high-temperature sintering, and its electrochemical oscillation was studied in LIBs. The electrochemical oscillation arose when the as-prepared Li4Ti5O12 precursor was sintered in a powder (not pellet) form, and it became stronger by reducing the lithium content in Li4Ti5O12. There are two types of electrochemical oscillation as a single-period oscillation or a double-period oscillation, and they can be transformed through varying the operating temperature, the current rate, and the conductive agent ratio, which might be owing to the electrochemical kinetics of Li4Ti5O12 electrodes. Combining the sintered forms and the X-ray photoelectron spectroscopy results, whether there is some fresh surface (formed by grinding the sintered pellet) becomes a typical difference between the powder-sintered and pellet-sintered Li4Ti5O12, which would affect the nucleation step and the reaction kinetics, and we proposed a possible reaction process of the electrochemical oscillation during the galvanostatic charging process of Li4Ti5O12 in LIBs.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2022
·
IF 4.598
Fangxu Hu,Yuanyuan Ren,Langlang Chen,Yijin Sheng,Cheng Zheng,De Li,Yong Chen
The electrochemical oscillation of Li-ion batteries is a novel electrochemical phenomenon, which has been discovered in two-phase materials of Li 4 Ti 5 O 12 and LiCrTiO 4 . To analyze the electrochemical oscillation in this work, a three-electrode coin cell was designed and assembled with a specialized reference electrode, based on the conventional two-electrode coin cell. In the three-electrode coin cell, a Li-deficient Li 4 Ti 5 O 12 material exhibits a distinct electrochemical oscillation during the galvanostatic charge process, and its electrochemical kinetics was studied by in-situ electrochemical impedance spectroscopy (EIS). Compared with two other Li 4 Ti 5 O 12 materials without electrochemical oscillation, the Li-deficient Li 4 Ti 5 O 12 material had an evidently larger resistance of the SEI layer (R sei ) and charge transfer resistance (R ct ) in the EIS spectra. When the electrochemical oscillation emerged, the Warburg impedance (W s ) dramatically transformed into the capacitive impedance in the EIS spectra, indicating that the intraparticle phase separation had been replaced by the interparticle phase separation. This study further confirmed the reaction process of electrochemical oscillation proposed in our previous work, so as to finally reveal the underlying mechanism of this novel phenomenon.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Juan Chen,Lin Hu,Gang Hu,Yu Zhang,Yuanyuan Hu,Jimei Song
In the analytical field, previous applications of chemical oscillation focused on quantitative analysis. We report in this paper a novel qualitative method electrochemically distinguishing two positional isomers by utilizing their perturbation effects on a catalyzed Briggs–Rauscher (BR) oscillation. The catalyst in the system is a macrocyclic nickel (II) complex NiL(ClO 4 ) 2 , where the ligand L in the complex is 5,7,7,12,14,14-hexemethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The experimental results indicated that addition of cyclohexane-1,3-dione (1,3-CHD) or 1,4-cyclohexanedione (1,4-CHD) could affect the profiles of potentiometric oscillations, but their changes in the profiles are greatly different. When 1,3-CHD was injected into the oscillating system, there was an initial spiking of the oscillations, accompanying by quenching of oscillations before the regeneration of oscillations. While 1,4-CHD was injected into the dynamic mixture, the oscillatory system responded to the perturbation with only slight decrease followed by a sharp increase in the potential, before it resumed to its normal oscillation state. The perturbation of 1,3-CHD involves inhibition time, whereas the perturbation of 1,4-CHD does not. Hence these two positional isomers could be distinguished by using their different perturbation effects on a BR dynamic system in the range of 9.0 × 10 −4 to 8.0 × 10 −3 M. Our assumption is that, perturbation of 1,3-CHD on the oscillating system involves a radical oxidization process to produce carboxylic acid, whereas perturbation of 1,4-CHD assumes idiodation and elimination steps to form 1,4-benzoquinone. Such different perturbation mechanisms are responsible for the difference in potentiometric oscillation profiles change. This hypothesis was confirmed by products analysis by FTIR and UV spectra.
研究领域:
分析化学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Electrochemical Science
·
2023
·
IF 1.5
Saif Ullah,Rooh Ullah,Rasha M.K. Mohamed,Gang Hu,Ateeq ur rehman,Muhammad Yasir Nawabi,Asif Hayat,Ata Ur Rehman,Mehboob Hassan,Ikram Uddin,Syed Attaullah Shah,Muhammad Zahir Shah,Jimei Song
An appropriate analytical technique for determination of kaempferol (KMF) by its perturbation effect on Belousov-Zhabotinskii (B-Z) oscillating system was reported. The macrocyclic copper (II) complex [CuL] (ClO 4 ) 2 ] was used as a catalyst while malic acid as substrate in B-Z system. The ligand L in the macrocyclic-complex is 5, 7, 7, 12, 14, 14-hexamethyl-1, 4, 8, 11-tetraazacyclotetradeca-4, 11-diene. Experimental outcomes shown the perturbation effect of KMF could cause the change in the amplitude of oscillation (ΔA) which was directly related to its concentration (2.5 × 10 -6 to 3.0 × 10 -4 mol/L) with correlation coefficient of 0.99315. The calculated relative standard deviation (RSD) is 3.1 % by eight samples (1.8 × 10 -5 mol/L) and the observed lower limit of detection is 1.25 × 10 -6 mol/L. The cyclic voltammetry (CV) experiments were used to confirm the redox reaction between kaempferol and sodium bromate. Furthermore, the reaction perturbation mechanism was derived from the well-known FKN (Field-Koros-Noyes) oscillation mechanism.
研究领域:
分析化学
·
生物化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2018
·
IF 3.235
Wangning Zhang,Waqar Uddin,Gang Hu,Lin Hu,Zhaohui Fang
A novel method for identification of four isomers of dihydroxynaphthalene (DHN) was reported by their different perturbation effects on a Briggs-Rauscher (BR) oscillating system. In the system, macrocyclic nickel (II) complex NiL(ClO 4 ) 2 is used as the catalyst, where the ligand L in the complex is 5,7,7,12,14,14‑hexemethyl‑1,4,8,11‑tetraazacyclotetradeca‑4,11‑diene. By putting equal amount of the same concentrations of four isomers (1,4‑dihydroxynaphthalene (1,4-DHN), 1,5‑dihydroxynaphthalene (1,5-DHN), 2,3‑dihydroxynaphthalene (2,3-DHN) and 2,7‑dihydroxynaphthalene (2,7-DHN)) into BR system, the system could or couldn't be perturbed, being reflected in quite different oscillating behaviors after addition of isomers. These four isomers were identified in their concentration range of 5.0 × 10 −6 to 2.5 × 10 −4 mol/L. An explanation of such perturbation mechanism is that, 1,4-DHN couldn't be oxidized by BR matrix, but 1,5-DHN, 2,3-DHN and 2,7-DHN could be oxidized by HOO to yield 5‑Hydrox‑1,4‑naphthoquinone, phthalic acid and 6,7‑dihydroxyperylene‑1,12‑quinone (DHPQ), respectively.
研究领域:
分析化学
·
物理化学
·
化学生物学
·
反应动力学
·
分子识别
✓ 已验证
DOI
高影响因子
RSC Advances
·
2024
·Vol. 14
·期 30
·21799-21807
·
IF 3.9
Yijin Sheng,Fangxu Hu,Yu Wu,De Li,Wenting Ji,Yong Chen
The electrochemical oscillation in Li-ion batteries has been reported for two-phase electrode materials of Li4Ti5O12 and LiCrTiO4, which is originated from the group-by-group phase transition in a multi-particle electrode. For both Li4Ti5O12 and LiCrTiO4, the electrochemical oscillation exhibits usually during charging, while rarely for discharging. Herein, a series of Zr-modified Li4Ti5O12 samples are prepared by using the spray-drying combined with high-temperature sintering method, and the electrochemical oscillation is observed during not only the charging process, but also the discharging process, which gradually grows up and then disappears by increasing the Li content. Compared with Li4Ti5O12, the specific capacity of Zr-modified Li4Ti5O12 decreases gradually by increasing the Zr/Ti ratio, owing to the impurity phases. According to the XRD, XPS and STEM results, the Zr element tends to accumulate on the surface to form ZrO2 nanoparticles, rather than dope into the bulk phase of Li4Ti5O12, which makes Li4Ti5O12 particles well dispersive. In contrast to the Li deficiency for only charging, the electrochemical oscillation during both charging and discharging should be attributed to the Li excess, but too much Li2TiO3 phase will suppress the electrochemical oscillation. Therefore, the Li excess can induce the electrochemical oscillation during both charging and discharging of Zr-modified Li4Ti5O12, which can be adopted to investigate the electrochemical oscillation of other materials in LIBs.
研究领域:
材料科学
·
电化学
·
电池技术
·
纳米技术
✓ 已验证
DOI
高影响因子
RUSSIAN JOURNAL OF ELECTROCHEMISTRY
·
2022
·Vol. 57
·期 12
·1213-1223
·
IF 1.351
Uddin W.,Nawabi M. Y.,Rehman S. Ur.,Hu G.,Khan J.,Shen X.
Abstract We introduced a novel technique for monitoring the activity of analytes for the first time. The technique is built upon the inhibitory effect caused by the free-radical-scavengers on the pattern of novel Briggs–Rauscher (BR) electrochemical oscillator catalyzed by tetra-aza-macrocyclic complex catalyst ([NiL](ClO 4 ) 2 . The ligand “L” in the complex is 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-diene. The effect involves a sudden ceasing of oscillation, an inhibition time ( t in ) that directly proportional to the amount of additive ( p -Dimethylaminobenzaldehyde ( p -DMAB)) added, and subsequent restoration of oscillations. Thus, a linear regression curve between concentrations range of 2.7 × 10 –7 mol L –1 to 4.5 × 10 –6 mol L –1 p -DMAB Vs t in was achieved with a correlation coefficient of 0.98. The observed limit of detection (LOD) is 2.7 × 10 –7 mol L –1 while the RSD calculated from 7 measurements of 2.5 × 10 –6 mol L –1 p -DMAB is 1.5%. Factors that influence the determination of p -DMAB were also studied. The mechanistic interpretation of the perturbed oscillation was anticipated from both NF and FCA models. A fleeting elucidation is that the intermediate species (HOO • ) produced during oscillatory reactions and reacted with p ‑DMAB. As a result, the oscillation was temporarily ceased.
研究领域:
分析化学
·
电化学
·
化学动力学
·
光谱学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）