CHINESE JOURNAL OF CHEMICAL PHYSICS
·
2023
·Vol. 36
·期 1
·103-112
·
IF 1
Mo Guang-shuai,Ge Kang-kang,Liu Guang-ming
Specific energy and self-discharge are two important performances of electrochemical capacitors. In this work, we have fabricated the composite electrodes by complexing the negatively charged carboxylated multi-walled carbon nanotubes (cMWCNT) with the redox active units-containing positively charged random copolymers. 2,2,6,6-Tetramethylpiperidinyl- N -oxyl and viologen are employed as model redox active units to exemplify the strategy of the concurrent increase of specific energy and suppression of self-discharge of a two-electrode device. The slower hydrogen and oxygen evolution reactions compared with the reactions of the redox active units lead to an increased electrolyte decomposition window, thereby giving rise to an increase in specific energy. On the other hand, the complexation between the cMWCNT and the copolymers suppresses both the redox shuttling and the cross-diffusion of the redox active units-containing polymer chains, leading to an improved performance of self-discharge. Based on the complexation between carbon nanotubes and redox active units-containing charged copolymers, this work provides a convenient and universal strategy to concurrently increase specific energy and suppress self-discharge of electrochemical capacitors.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
TALANTA
·
2024
·
IF 5.6
Peng’an Zhu,Jiangle Zhang,Jingjing Jin,Xing Huang,Xinfeng Zhang
Ferrous ion (Fe 2+ ) can indicate the redox situation of water and also plays an important role in maintaining the ecological balance of water bodies. However, due to the redox-active property of Fe 2+ , it is still a huge challenge to sensitively and accurately determine Fe 2+ especially in interstitial water. Herein, we prepared a ferrozine gel rod for valence fixation during sampling and subsequent smartphone-based detection of Fe 2+ . The electrode potential of the redox pair can be varied through the formation of Fe 2+ -ligand complexes, and when E complex was higher than E O 2 / OH − , the oxidation of Fe 2+ by O 2 was hindered, thus achieving the valence fixation of Fe 2+ . Six ligands were screened, and it was found that ferrozine could effectively increase the redox potential after complexing with Fe 2+ , and also exhibits an obvious color change while fixing the valence of Fe 2+ . To facilitate Fe 2+ detection, a cross-linked porous polymer gel rod prepared by acrylamide and sodium alginate was used to encapsulate the ferrozine molecules. The ferrozine gel rod enabled fixation the valence of Fe 2+ longer than 30 days, and the resulted purple-red color was pictured and analyzed by a smartphone. Ultimately, the developed ferrozine gel rod sensing system was able to achieve sensitive and linear detection of Fe 2+ in the range of 1–200 μM with the limit of detection as low as 0.33 μM, and it also exhibited excellent selectivity and anti-interference ability. The accuracy and reliability of the method was verified by the determination of Fe 2+ in spiked water samples and certified standard reference water samples. Finally, the ferrozine gel rod sensing system was successfully applied to in-situ detection of Fe 2+ in interstitial water, overlying water and upper water of lake and river. This facile system that enabled valence fixation and fast detection is promising for detection of Fe 2+ in environmental waters.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
WATER RESEARCH
·
2020
·
IF 9.13
Ya Wang,Jiahai Ma
Natural dissolved organic matter (DOM) is ubiquitous in environment and plays an important role in numerous environmental processes. Although the molecular basis of the reactivity of DOM remains poorly understood due to its extreme complexity, redox-active carbonyls (aromatic ketones/aldehydes and quinones) within DOM are believed vitally important. Except the rough determination of total carbonyls (including non-redox active –COOR) based on inflexible 13 C chemical shift range by expensive and time-consuming solid-state nuclear magnetic resonance (NMR), there is no ready method to quantify redox-active carbonyls in DOM. Here we show that after treatment with sodium borohydride (NaBH 4 ) by selectively eliminating redox-active carbonyls, quenched fluorescence of carbon quantum dots (CD) by DOM recovered dramatically, and displayed a good linear relationship between redox-active carbonyls detected and DOM concentration ( R 2 ≥ 0.977 ), thus allowing first quantitative determination of the redox-active carbonyls of DOM. Eight DOM isolates present 0.59%–0.90% redox-active carbonyls by the current method. And this method is robust from coexisting proteins and salts. This method could provide better or equal instructive results compared with solid-state NMR for total carbonyls or electrochemical method for electron-accepting capacities (EAC). Our results provide the underlying structural basis of many important geochemical processes that mediated by DOM. We posit that this method could apply to other complex molecular systems such as the atmospheric aerosols and extracellular polymeric substances (EPS), too.
研究领域:
环境科学
·
分析化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2014
·Vol. 161
·期 4
·H249
·
IF 2.859
Yong Kong,Yan Sha,Shengkai Xue,Yong Wei
A novel conducting polymer, poly(aniline-co-p-aminobenzoic acid) (PAABA), was successfully synthesized via electrochemical copolymerization of aniline and p-aminobenzoic acid (p-ABA) in 2 M H2SO4 solution. The results of FTIR and SEM revealed the differences between the obtained copolymer and its two corresponding homopolymers. Compared to polyaniline which has a rather limited useful pH range, PAABA presents excellent redox activity from pH < 1.0 to pH 10.0. The ion exchange properties of the copolymer were also investigated by using electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry, demonstrating a special anion exchange behavior different from polypyrrole. In other words, the spatial structure of anions instead of the radius of anions studied plays a key role in the anion exchange affinity sequence.
研究领域:
材料科学
·
电化学
·
高分子化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE BRAZILIAN CHEMICAL SOCIETY
·
2020
·Vol. 31
·期 1
·25-32
·
IF 1.399
Meiqin,Zhu Jingjing,Fan Rongrong,Wang Yujie,Lv Zhaojun,Han Yongming,Peng Jun,Zheng Xinyu,Lin Ruiyu
High specific surface area activated carbon prepared by Perilla frutescens (PFHSAAC) was modified on the surface of the glassy carbon electrode (GCE) by drop-coating method to construct a PFHSAAC/GCE. The electrochemical properties of the modified electrode were investigated in detail by some electrochemical methods such as cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). Experiment results show that the modified electrode has excellent redox activity and distinction capability toward the two isomers of catechol (CC) and hydroquinone (HQ). The separation of oxidation peak potential for HQ and CC of DPV is 112.8 mV. Under the optimal conditions, the oxidation peak currents of HQ and CC show good linear relationships with their concentrations in the ranges of 1.0 × 10-6-2.0 × 10-4 and 1.0 × 10-6-1.5 × 10-4 mol L-1, respectively. The limits of detection for HQ and CC are 3.57 × 10-7 and 4.23 × 10-7 mol L-1, respectively. The PFHSAAC/GCE exhibits good stability, repeatability and sensitivity. The developed method was used to determine HQ and CC in water samples with best results.
研究领域:
分析化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Energy Materials
·
2023
·
IF 6.4
Jiaqi Xu,Zhoulin Ye,Zongcai Deng,Dongchu Chen,Qilang Lin,Dongyang Chen
Polymer batteries have attracted increasing attention because of their advantages of good flexibility, high compatibility with organic electrolytes, and high environmental friendliness. However, the low utilization rate of the redox-active units buried in polymeric network and the slow kinetics of the electrochemical reactions hinder their development. Herein, mono- and diviologen functionalities are attached to a tetramethylbiphenol-derived poly(arylene ether ketone) (TPAEK) by postmodification to yield two redox-active polymers MV-TPAEK and 2MV-TPAEK, respectively, and polymer electrodes are prepared by mixing them with N-doped carbon nanotubes without binders. When paired with the Li counter electrode, the MV-TPAEK and 2MV-TPAEK electrodes deliver specific discharge capacities of 93.3 and 95.4 mA h g–1, respectively, at a current rate of 0.1 C and maintain 36.1 and 42.3 mA h g–1, respectively, after 100 galvanostatic cycles. When the current rate is increased to 10 C, the specific discharge capacities are lowered to 13.9 and 25.8 mA h g–1, respectively, for the MV-TPAEK and 2MV-TPAEK electrodes due to the increased electrochemical polarizations. All of these results prove that the 2MV-TPAEK electrode is better than the MV-TPAEK electrode. When the counter electrode is changed to Na, the trend remains the same. Given the fact that the two polymers have an identical backbone, the improved electrochemical performance of 2MV-TPAEK may be ascribed to the larger mobility of the extended 2MV pendant, which is beneficial for the formation of more molecular voids and stacked intermediate structures for better charge transfer. This study paves the way for the molecular design of redox-active polymers for high-performance polymer batteries.
研究领域:
材料科学
·
电化学
·
高分子化学
✓ 已验证
DOI
高影响因子
Energy Storage Materials
·
2020
·
IF 16.28
Yue Xu,Jing Wan,Li Huang,Jia Xu,Mingyang Ou,Yi Liu,Xueping Sun,Shuai Li,Chun Fang,Qing Li,Jiantao Han,Yunhui Huang,Yusheng Zhao
Prussian Blue Analogs (PBAs) such as copper hexacyanoferrate (CuHCF) are traditional intercalation cathodes for rechargeable Na-ion batteries. However, the electrochemical performance of these PBAs suffers from insufficient activation and sharp performance deterioration. Here, the insufficient electrochemical activity and frame deformation issues in the CuHCF cathodes were investigated to enhance their specific capacity and improve their cycling stability. The high-crystallinity CuHCF nanosheets (CuHCF-P) with low-water-content were synthesized by a pyrophosphate-assistant co-precipitation method. It has a highly reversible 1.5-Na insertion/desertion capability with a specific capacity of ~120 mAh g −1 at 0.1 C, which is the highest among all the CuHCF cathodes reported. First-principle study and XPS detection demonstrate that both Cu and Fe are redox-active centers in CuHCF-P cathode, which facilitates a high Na + storage capability. And the decrease of water content in CuHCF framework increases Fe/Cu 3 d -orbital occupy-sites, which activates both of the transition-metals. Furthermore, the full cells fabricated with as-prepared CuHCF-P cathode and commercial hard carbon anode exhibit excellent performances with a reversible capacity of 109 mAh g −1 at 0.1 C over 200 cycles.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
SYNTHETIC METALS
·
2020
·
IF 3.286
Xin Liu,Limin Zang,Chunliu Liang,Qifan Liu,Yan Deng,Chao Yang,Jianhui Qiu
The flexible fiber-shaped electrodes that polypyrrole (PPy) and hydroquinone (HQ) derivatives coated on the surface of carbon fiber yarn (CFY) were synthesized by a simple one-step electrosynthesis. Besides, the effects of the size and structure of the HQ derivatives on the electrochemical performance of the doped PPy@CFY electrodes were analyzed. The study suggested that sodium lignosulfonate doped PPy@CFY (LS-PPy@CFY) exhibited a high specific capacitance of 245.89 F cm −3 at 0.26 A cm −3 . The all-solid-state flexible fiber-shaped supercapacitor (AFFSC) based on two parallel LS-PPy@CFY electrodes showed a high specific capacitance of 50.08 F cm −3 and an excellent energy density of 4.45 mW h cm −3 . Moreover, the AFFSC achieved prominent cyclic stability, maintaining 92.7% capacitance retention after 25,000 cycles, as well as excellent flexibility and mechanical stability which kept 89% capacitance retention after 5000 bending cycles. In addition, the AFFSC also exhibited good voltage and current scalability and potentiality in its practical application.
研究领域:
材料科学
·
能源存储
·
电化学
✓ 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）