POLYMER DEGRADATION AND STABILITY
·
2024
·
IF 6.3
Chunyang Li,Duo Ji,Yuxin Wan,Xu Yang,Manzhi Shao,Hong Zhao,Jiansheng Sun
Surface discharge on the EPDM/XLPE interface is threatening the safe operation of power cable system and limiting the further improvement of its voltage level. To improve the electrical strength of EPDM/XLPE interface, the surface of EPDM was modified by grafting of voltage stabilizer 4-allyloxy-2-hydroxybenzophenone (AOHBP) based on liquid-phase impregnation and subsequent free radical grafting reaction thermally initiated by DCP. EPDM samples were modified by mixed reagents of DCP and AOHBP with different mass ratios of 1:2, 1:3 and 1:4, respectively. The SEM observation and XRD analysis results indicate that the crystals of AOHBP with a uniform distribution are covered on the surface of EPDM during the sample preparation process and then dissolved after extraction by acetone. The FTIR and ATR results show that the AOHBP molecules are successfully grafted onto the surface of EPDM samples, but there remain a lot of ungrafted reagent molecules on the surface of EPDM before solvent extraction. The grafting rate of AOHBP increases with the proportion of DCP in the mixed reagents. As for the unextracted modified EPDM samples, both the AC and DC breakdown voltage of the EPDM/XLPE interface are increased compared with pure EPDM, and further increased after the ungrafted molecules are extracted because the effect of voltage stabilizer on scavenging high-energy electrons is more efficiently utilized at a smoother interface. The interface breakdown voltage of the sample modified with 1:2 mass ratio of DCP/AOHBP mixed solution is the highest because of its highest grafting rate of voltage stabilizer. This work has proposed a new technical path to improve the electrical aging resistance of polymer insulating surface.
研究领域:
高分子材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2019
·Vol. 11
·期 1
·176
·
IF 3.164
Wei Dong,Xuan Wang,Bo Tian,Yuguang Liu,Zaixing Jiang,Zhigang Li,Wei Zhou
Aromatic voltage stabilizers can improve the dielectric properties of cross-linked polyethylene (XLPE); however, their poor compatibility with XLPE hinders their practical application. Improving the compatibility of aromatic voltage stabilizers with XLPE has, therefore, become a new research goal. Herein 1-(4-vinyloxy)phenylethenone (VPE) was prepared and characterized. It can be grafted onto polyethylene molecules during the cross-linking processes to promote stability of the aromatic voltage stabilizers in XLPE. Fourier transform infrared spectroscopy confirmed that VPE was successfully grafted onto XLPE, and effectively inhibited thermal migration. Thermogravimetric analysis showed that the grafted VPE/XLPE composite exhibits a better thermal stability than a VPE/PE blend composite. Evaluation of the electrical properties showed that the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 15.5% and 39.6%, respectively, when compared to those of bare XLPE. After thermal aging, the breakdown strength and electrical tree initiation voltage of the VPE/XLPE composite were increased by 9.4% and 25.8%, respectively, in comparison to those of bare XLPE, which indicates that the grafted voltage stabilizer can effectively inhibit its migration and enhance the stability of the composite material.Keywords:cross-linked polyethylene;grafted voltage stabilizer;breakdown strength;electrical tree initiation voltage
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Chinese Physics B
·
2017
·Vol. 26
·期 1
·018401
·
IF 1.223
Chao Xia,Wei-Dong Song,Chong-Zhen Zhang,Song-Yang Yuan,Wen-Xiao Hu,Ping Qin,Ru-Peng Wang,Liang-Liang Zhao,Xing-Fu Wang,Miao He,Shu-Ti Li
The anomalous hysteresis in a perovskite solar cell induced by an asymmetric field is confirmed by a capacitance–voltage measurement. By applying several cycles of alternating reverse and forward scans, this hysteresis phenomenon is obviously alleviated, resulting in a hysteresis-less state in the perovskite solar cell. Meanwhile, the open-circuit voltage and power conversion efficiency of the perovskite solar cell are enhanced by 55.74% and 61.30%, respectively, while the current density and fill factor keep almost invariable. The operation of alleviating hysteresis is essential for further research and is likely to bring in performance gains.
研究领域:
材料科学
·
能源研究
·
光伏技术
✓ 已验证
DOI
高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2025
·Vol. 172
·期 4
·040508
·
IF 3.3
Xiaola Li,Huihong Gong,Wenjie Huang,Wenzhao Huang,Ziyang Liang,Yuqing Liu,Boyang Zhang,Shuxing Wu,Chenyu Liu,Zhan Lin,Dong Luo
Li-rich Mn-based layered oxides (LLOs) are regarded as one of the most promising next-generation cathodes for lithium-ion batteries (LIBs) due to their ultra-high capacity and low cost. However, the redox behavior of oxygen under high voltage induces severe challenges, including voltage hysteresis and voltage decay, which have become major obstacles to their commercialization. This work optimizes the oxygen redox process of O2-type LLOs by regulating the Na content in P2-type Na-based intermediates. Experimental results demonstrate that samples prepared by intermediates with optimal Na content show higher reversibility and reduction potential of oxygen redox. Meanwhile, the migration and dissolution of transition metals in the optimized samples are effectively suppressed. Therefore, the optimized samples deliver an improved voltage stability and alleviated voltage hysteresis. This work suggests that the oxygen redox process can be regulated and provides a practical solution to mitigate voltage decay and hysteresis in LLOs.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Electronic Materials
·
2023
·
IF 4.7
Guozhang Ren,Shunhao He,Yulong Zhang,Chengcheng Zhu,Zhongyan Gong,Kaili Wang,Linrong Zhang,Zhuoyao Li,Gang Lu,Hai-Dong Yu
As a next-generation electronic device, the organic electrochemical transistor (OECT) is widely spreading in laboratory research and has many practical applications because of the advantages of its simple structure, low operating voltage, and high biocompatibility. However, the evaluation of the performance of OECTs is generally chaotic since there are many testing methods that may yield different results. Herein, we reveal that the testing protocols may largely affect the obtained results of the same OECT. An increase in the sweeping speed of the gate voltage could lead to a drop in the measured performance of OECTs. When a pulsed voltage was applied on the drain electrode, a degradation in the performance of OECTs could also be observed at a short pulse width. This work clarifies the influence of testing methods on the performance evaluation of OECTs. As a result, the development of the field of the synthesis of OECTs may be significantly promoted.
研究领域:
电子学
·
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Wenhu Yang,Jian Wang,Suibin Luo,Shuhui Yu,Haitao Huang,Rong Sun,Ching-Ping Wong
Overvoltage protection is becoming increasingly important because of miniaturization and multifunctionality of electronic devices. Flexible, easily processable materials with nonlinear and reversible I–V behavior are highly desired. In this study, hybrid nanoparticles of ZnO-decorated carbon nanotubes (CNT–ZnO) were synthesized via a sol–gel hydrothermal process employed in an epoxy matrix to prepare composites. Microstructure analysis demonstrated that ZnO nanoparticles were well-bonded to the surface of CNT. The CNT–ZnO/epoxy composites exhibited nonlinear I–V behavior under increasingly applied voltage with a nonlinear coefficient of 5.01 (10 wt % filler loading). More importantly, the composites possessed excellent reversibility from dielectric to conductor and vise versa in the recycling of increase and decrease of applied electric field, in contrast to the poor recoverability of pure CNT-filled epoxy. The mechanism of the nonlinear I–V behavior and reversibility was investigated and discussed. A simple circuit was fabricated, which verified well the protection function of the CNT–ZnO/polymer composites.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Energy Materials
·
2020
·
IF 4.473
Chuan-Wei Wang,Yao Zhou,Jin-Hai You,Jian-De Chen,Zheng Zhang,Shao-Jian Zhang,Chen-Guang Shi,Wei-Dong Zhang,Ming-Hua Zou,Yang Yu,Jun-Tao Li,Lei-Ying Zeng,Ling Huang,Shi-Gang Sun
The LiCoO2 (LCO) cathode has been widely used in material markets, especially in conventional lithium ion batteries, due to its stable electrochemical performance. Increasing the working cutoff potential represents an efficient pathway to boost the capacity of LCO batteries; however, high working potentials usually induce severe Co3+ dissolution and extensive growth of solid electrolyte interphase (SEI) layer, leading to rapid degradation of the electrochemical performance. In this work, a high voltage cathode is prepared by the encapsulation of aluminum (Al)-doped LiCoO2 in a continuous Li4Ti5O12 (LTO) layer using a high-speed solid-phase coating method. The chemical composition evolution of the coating layer during the cycling process was characterized and evaluated through in situ XRD, XPS, and XAS analyses. The precipitation of aluminum fluoride (AlF3) at the defective sites of the LTO coating layer in the initial charge–discharge cycles effectively was found to fortify the structural integrity of the coating layer and prevent the etching of the LCO from undesirable side reactions with the liquid electrolyte. The modified LCO demonstrated an excellent capacity retention of 89.9% after 100 cycles at 0.2 C. The high-speed solid-phase coating method established in this study could be scaled up straightforwardly, providing a highly commercializable approach for large-scale production of stable high-voltage LCO cathode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2023
·Vol. 14
·期 1
·1-11
·
IF 16.6
Zhang Xiangyong,Wei Hua,Li Shizhen,Ren Baohui,Jiang Jingjing,Qu Guangmeng,Lv Haiming,Liang Guojin,Chen Guangming,Zhi Chunyi,Li Hongfei,Liu Zhuoxin
Aqueous copper-based batteries have many favourable properties and have thus attracted considerable attention, but their application is limited by their low operating voltage originating from the high potential of copper negative electrode (0.34 V vs. standard hydrogen electrode). Herein, we propose a coordination strategy for reducing the intrinsic negative electrode redox potential in aqueous copper-based batteries and thus improving their operating voltage. This is achieved by establishing an appropriate coordination environment through the electrolyte tailoring via Cl − ions. When coordinated with chlorine, the intermediate Cu + ions in aqueous electrolytes are successfully stabilized and the electrochemical process is decoupled into two separate redox reactions involving Cu 2+ /Cu + and Cu + /Cu 0 ; Cu + /Cu 0 results in a redox potential approximately 0.3 V lower than that for Cu 2+ /Cu 0 . Compared to the coordination with water, the coordination with chlorine also results in higher copper utilization, more rapid redox kinetics, and superior cycle stability. An aqueous copper-chlorine battery, harnessing Cl − /Cl 0 redox reaction at the positive electrode, is discovered to have a high discharge voltage of 1.3 V, and retains 77.4% of initial capacity after 10,000 cycles. This work may open up an avenue to boosting the voltage and energy of aqueous copper batteries.
研究领域:
电化学
·
材料科学
·
电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Recent Patents on Nanotechnology
·
2020
·Vol. 14
·期 1
·42-45
·
IF 0.977
Li Xiao-Xia,He Ji-Huan
Background: The patented bubble electrospinning, which is a simple and effective technique for mass-production of polymer nanofibers, has been studying extensively, but it is still under development. In the bubble electrospinning, multiple jets move from the positive electrode to the
receptor, a long distance between the two electrodes is needed to guarantee complete solvent evaporation, as a result a relative high voltage is needed. Objective: The aim of the present study is to use an auxiliary electrode and an auxiliary air flow to improve bubble electrospinning
with lower voltage and higher output than those by its traditional one. Methods: The modification of the bubble electrospinning with an auxiliary electrode and an auxiliary airflow is used to fabricate nanofibers. The auxiliary electrode is close to the positive electrode. The experiment
was carried out at room temperature with 8%PVA solution. The result was analyzed with a S4800 cold field scanning electron microscope (SEM, Hitachi S-4800, Tokyo, Japan). Results: The auxiliary electrode can generate a strong induced electric field force. With the action of airflow, the
jets will fly to the receptor instead of the auxiliary electrode. Conclusion: Both auxiliary electrode and auxiliary airflow are two important factors affecting the spinning process. It can reduce the spinning voltage and improve spinning efficiency.
研究领域:
材料科学
·
生物工程
✓ 已验证
DOI
PubMed
高影响因子
Crystals
·
2022
·Vol. 12
·期 2
·163
·
IF 2.67
Xiangshen Meng,Jian Li,Yueqiang Lin,Xiaodong Liu,Jianwei Zhao,Decai Li,Zhenghong He
The electro-optical features of the PDLC films applied with a low-frequency square wave voltage were investigated. The transmittance curves indicated the double frequency of the applied voltage at 0–50 Hz, which resulted from the relaxation of an internal electric field polarized by ions in LC droplets. When the local electric field was reversed, the internal polarization electric field could be maintained and superimposed on the local electric field. The relaxation of the internal polarized electric field resulted in the relaxation of the transmittance. Furthermore, the transmittance curves changed with the frequency of the applied voltage.Keywords:PDLC;ion;square-wave voltage;effective electric field
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2021
·
IF 9.127
Bei Hu,Fushan Geng,Ming Shen,Chong Zhao,Qing Qiu,Yang Lin,Changxin Chen,Wen Wen,Shun Zheng,Xiaoshi Hu,Chao Li,Bingwen Hu
LiCoO 2 , as a domain cathode material of Li-ion batteries, faces a great deal of challenges due to the limited cycling stability at high voltage (>4.35 V vs. Li/Li + ). These issues are tentatively addressed here by a multifunctional self-stabilization modification strategy, involving trace Mg bulk doping, surface gradient Ti doping and BaTiO 3 dot coating in LiCoO 2 . The multifunctional synergy is verified to overcome the detrimental irreversible phase transition and the growth of impedance of LiCoO 2 cycling at 4.6 V. By using soft X-ray absorption spectroscopy (sXAS) and electron paramagnetic resonance (EPR) techniques, we also elucidate that Ti surface gradient doping can reinforce the structure rigidity of the particles while significantly attenuates the irreversible oxygen redox at high voltage. All these strategies promote the prolonged cyclic performance of LiCoO 2 under 4.6 V high-voltage through different mechanism. This elaborate investigation provides an instructive contribution in the advancement of high-voltage LiCoO 2 .
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2024
·
IF 3.7
Teng Li,Ruizi Wang,Zikang Cai,Wenzhe Liu,Jiwei Song,Xixi Wu,Chunyan Cao,Liangjie Yuan
To date, LiCoO 2 has received extensive attention as a cathode material because of its unique characteristics. To satisfy the strong demand for high energy density , the cut-off voltage of LiCoO 2 is continuously increased. However, the structural instability of LiCoO 2 at a high cut-off voltage leads to capacity decay and many safety issues, which hinder further application of LiCoO 2 . Herein, YPO 4 is used to achieve a better electrochemical performance for LiCoO 2 at 4.55 V. In the synthesis process, YPO 4 is transformed into the Li 3 PO 4 and Y 2 O 3 phases, which are basically uniformly incorporated into the particle and form a composite with LiCoO 2 . Owing to the synergistic modification of Li 3 PO 4 and Y 2 O 3 phases, YPO 4 -modified LiCoO 2 materials show enhanced structural stability and excellent cycling performance. Particularly, 1.5% YPO 4 modified LiCoO 2 not only exhibits a reversible discharge capacity of 171.6 mAh g −1 over 500 cycles with 91.7% capacity retention, but also delivers a capacity of 144.5 mAh g −1 at 5 C (1 C = 274 mAh g −1 ). This work suggests that using rare-earth metal phosphates can be an effective strategy to improve the cycling performance of LiCoO 2 at 4.55 V.
研究领域:
材料科学
·
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）