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1.
Yanzhuo Lv  Lulu Bao  Fei Meng  Xiang Gao 《Ionics》2018,24(6):1715-1720
The electrochemical behaviors of Mg-5Li-3Al-1La and Mg-8Li-3Al-1La electrodes in NaCl solution are investigated by means of potentiodynamic polarization, potentiostatic oxidation, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). It is found that the Mg-8Li-3Al-1La electrode is of higher discharge activity than the Mg-5Li-3Al-1La electrode in 0.7 mol L?1 NaCl solution, which is consistent with the results observed from SEM images. The composition of the discharging products is also analyzed by means of XRD diffraction. This result shows that the Mg-8Li-3Al-1La alloy displays better compatibility with salt than the Mg-5Li-3Al-1La alloy, and the electrolyte can easily permeate the electrode, which enlarges the reaction zone and improves the activity of the electrode. The continuous discharging utilization efficiency of the Mg-5Li-3Al-1La and Mg-8Li-3Al-1La electrodes is 47.36 and 50.46%, respectively. The utilization of the Mg-Li-Al-La electrode is increased by 3.10% with the amount of Li increased from 5 to 8%. Meanwhile, the interval discharging utilization efficiency of the two electrodes is 46.13 and 49.88%, respectively, and the increase in the amount of Li in the electrode also brings a favorable effect on the interval electrochemical properties of the electrode.  相似文献   

2.
S. Abarna  G. Hirankumar 《Ionics》2017,23(7):1733-1743
Novel solid polymer electrolytes, poly(vinylalcohol)-lithium perchlorate (PVA-LiClO4) and PVA-LiClO4-sulfolane are prepared by solvent casting method. The experimental results show that sulfolane addition enhances the ionic conductivity of PVA-LiClO4 complex by three orders. The maximum ionic conductivity of 1.14 ± 0.20 × 10?2 S cm?1 is achieved for 10 mol% sulfolane-added electrolyte at ambient temperature. Polymer-salt-plasticizer interactions are analyzed through attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Lithium ion transference number is found by AC impedance spectroscopy combined with DC potentiostatic measurements. The results confirm that sulfolane improves the Li+ transference number of PVA-LiClO4 complex to 0.77 from 0.40. The electrochemical stability window of electrolytes is determined by cyclic voltammetry (CV). The broad electrochemical stability window of 5.45 V vs. lithium is obtained for maximum conducting electrolyte. All-solid-state cell is fabricated using maximum conducting electrolyte, and electrochemical impedance study is carried out. It reveals that electrolyte interfacial resistance with Li electrode is very low. The use of PVA-LiClO4-sulfolane as a viable electrolyte material for high-voltage lithium ion batteries is ensured.  相似文献   

3.
Different SnO2 nanostructures (SnO2Ns) were directly electrodeposited on the surface of anodized copper (Cu) substrates via the potentiostatic electrodeposition method with addition of supporting electrolytes. The effects of the supporting electrolytes and the electrodeposition parameters on the evolution of nanostructures and on the electrochemical properties of the SnO2Ns were systematically investigated using field emission scanning electron microscope (FESEM) and electrochemical methods including cyclic voltammetry (CV) and chronoamperometry (CA). The results confirmed that SnO2Ns exhibit alloying/de-alloying reactions with Li+ ions versus Ag/AgCl in aqueous electrolyte solution (LiOH·H2O and Li2CO3). The super capacitor performance of the SnO2Ns was investigated in 0.5-M Na2SO4 aqueous solution, and the highest specific capacitance of 110 Fg?1 at a scan rate of 5 mV s?1 was obtained for SnO2 microspheres made up of nanocubes. Our study shows that supporting electrolytes and electrodeposition parameters play the significant role in the growth of SnO2Ns and its electrochemical properties.  相似文献   

4.
In this paper, an ionic liquid 1-carboxyl-methyl-3-methylimidazolium tetrafluoroborate (CMMIMBF4)-functionalized Mg2Al layered double hydroxide (LDH) was synthesized and further used for the immobilization of myoglobin (Mb) on the surface of a carbon ionic liquid electrode to get a new electrochemical biosensor. Ultraviolet–visible and Fourier transform–infrared spectroscopies confirmed that Mb in the CMMIMBF4-LDH remained its native secondary structure, which was attributed to the biocompatibility of the materials used. On the cyclic voltammograms, a pair of well-defined redox peaks appeared, indicating that direct electron transfer of Mb was realized in the modified electrode. The formal peak potential was calculated as ?0.209 V (vs. SCE), which was the typical characteristics of the Mb heme Fe(III)/Fe(II) redox couples. The fabricated Mb sensor exhibited good electrocatalytic activity to the reduction of trichloroacetic acid in the range from 1.0 to 17.0 mmol L?1 with the detection limit as 0.344 mmol L?1 (3σ), and the apparent Michaelis–Menten constant was calculated as 13.5 mmol L?1. Thus, the ionic liquid-functionalized LDH exhibited the potential application in the electrochemical sensor for redox proteins.  相似文献   

5.
Nanocrystalline Li2TiO3 was successfully synthesized using solid-state reaction method. The microstructural and electrochemical properties of the prepared material are systematically characterized. The X-ray diffraction pattern of the prepared material exhibits predominant (002) orientation related to the monoclinic structure with C2/c space group. HRTEM images and SAED analysis reveal the well-developed nanostructured particles with average size of ~40 nm. The electrochemical properties of the prepared sample are carried out using cyclic voltammetry (CV) and chronopotentiometry (CP) using Pt//Li2TiO3 cell in 1 mol L?1 Li2SO4 aqueous electrolyte. The Li2TiO3 electrode exhibits a specific discharge capacity of 122 mAh g?1; it can be used as anode in Li battery within the potential window 0.0–1.0 V, while investigated as a supercapacitor electrode, it delivers a specific capacitance of 317 F g?1 at a current density of 1 mA g?1 within the potential range ?0.4 to +0.4 V. The demonstration of both anodic and supercapacitor behavior concludes that the nanocrystalline Li2TiO3 is a suitable electrode material for supercapattery application.  相似文献   

6.
The ionic liquid polymer electrolyte (IL-PE) membrane is prepared by ultraviolet (UV) cross-linking technology with polyurethane acrylate (PUA), methyl methacrylate (MMA), ionic liquid (Py13TFSI), lithium salt (LiTFSI), ethylene glycol dimethacrylate (EGDMA), and benzoyl peroxide (BPO). N-methyl-N-propyl pyrrolidinium bis(trifluoromethanesulfonyl)imide (Py13TFSI) ionic liquid is synthesized by mixing N-methyl-N-propyl pyrrolidinium bromide (Py13Br) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The addition of Py13TFSI to polymer electrolyte membranes leads to network structures by the chain cross-linking. The resultant electrolyte membranes display the room temperature ionic conductivity of 1.37 × 10?3 S cm?1 and the lithium ions transference number of 0.22. The electrochemical stability window of IL-PE is about 4.8 V (vs. Li+/Li), indicating sufficient electrochemical stability. The interfacial resistances between the IL-PE and the electrodes have the less change after 10 cycles than before 10 cycles. IL-PE has better compatibility with the LiFePO4 electrode and the Li electrode after 10 cycles. The first discharge performance of Li/IL-PE/LiFePO4 half-cell shows a capacity of 151.9 mAh g?1 and coulombic efficiency of 87.9%. The discharge capacity is 131.9 mAh g?1 with 95.5% coulombic efficiency after 80 cycles. Therefore, the battery using the IL-PE exhibits a good cycle and rate performance.  相似文献   

7.
To seek a promising candidate electrolyte at elevated temperature for lithium manganese oxide (LiMn2O4)/Li cells, the electrochemical performance of 0.7 mol L?1 LiBOB (lithium bis(oxalate)borate)-SL (sulfolane)/DEC (diethyl carbonate) (1:1, in volume) electrolyte was studied at 55 °C. The Mn dissolution in electrolyte was analyzed by inductively coupled plasma (ICP) analysis. AC impedance measurement and scanning electron microscopy (SEM) analysis were used to analyze the formation of the surface film on the LiMn2O4 electrode. The results demonstrate that the LiBOB-SL/DEC electrolyte can slow down the dissolution and erosion of Mn ions, and decrease the interface impedance. Moreover, the LiBOB-SL/DEC electrolyte could obviously improve the capacity retention, the operating voltage (4.05 V), and the rate performance of LiMn2O4/Li cells.  相似文献   

8.
Fluoroethylene carbonate (FEC) is investigated as the electrolyte additive to improve the electrochemical performance of high voltage LiNi0.6Co0.2Mn0.2O2 cathode material. Compared to LiNi0.6Co0.2Mn0.2O2/Li cells in blank electrolyte, the capacity retention of the cells with 5 wt% FEC in electrolytes after 80 times charge-discharge cycle between 3.0 and 4.5 V significantly improve from 82.0 to 89.7%. Besides, the capacity of LiNi0.6Co0.2Mn0.2O2/Li only obtains 12.6 mAh g?1 at 5 C in base electrolyte, while the 5 wt% FEC in electrolyte can reach a high capacity of 71.3 mAh g?1 at the same rate. The oxidative stability of the electrolyte with 5 wt% FEC is evaluated by linear sweep voltammetry and potentiostatic data. The LSV results show that the oxidation potential of the electrolytes with FEC is higher than 4.5 V vs. Li/Li+, while the oxidation peaks begin to appear near 4.3 V in the electrolyte without FEC. In addition, the effect of FEC on surface of LiNi0.6Co0.2Mn0.2O2 is elucidated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The analysis result indicates that FEC facilitates the formation of a more stable surface film on the LiNi0.6Co0.2Mn0.2O2 cathode. The electrochemical impedance spectroscopy (EIS) result evidences that the stable surface film could improve cathode electrolyte interfacial resistance. These results demonstrate that the FEC can apply as an additive for 4.5 V high voltage electrolyte system in LiNi0.6Co0.2Mn0.2O2/Li cells.  相似文献   

9.
Rusi  C.-K. Sim  S. R. Majid 《Ionics》2017,23(5):1219-1227
Polyaniline (PANI) nanowire electrode was successfully prepared using electrodeposition method. The morphology, thickness, and electrochemical performance of PANI electrode can be controlled by varying the deposition scan rates. Lower deposition scan rate results in compact and aggregates of PANI nanowire morphology. The uniform nanowire of PANI was obtained at the applied scan rate of 100 mV s?1, and it was used as symmetric electrode coupled with H2SO4/polyvinyl alcohol (PVA) gel electrolyte. The different concentrations of H2SO4 acid in polymer electrolyte have influenced the electrochemical performance as well. The optimum specific capacitance and energy density of P100 PANI electrode in 3 M H2SO4/PVA gel polymer electrolyte was 377 F g?1 and 95.4 Wh kg?1 at the scan rate of 1 mV s?1. The good stability of the electrode in this system is applicable to many wearable electronics applications.  相似文献   

10.
A new functionalized ionic liquid (IL) based on cyclic quaternary ammonium cations with ester group and bis(trifluoromethanesulfonyl)imide ([TFSI]?) anion, namely, N-methyl-N-methoxycarbonylpiperidinium bis(trifluoromethanesulfonyl)imide ([MMOCPip][TFSI]), was synthesized and characterized. Physical and electrochemical properties, including Li-ion transference number, ionic conductivity, and electrochemical stability, were investigated. The electrochemical window of [MMOCPip][TFSI] was 6 V, which was wide enough to be used as a common electrolyte material. The Li-ion transference number of this IL electrolyte containing 0.1 M LiTFSI was 0.56. The half-cell tests indicated that the [MMOCPip][TFSI] obviously improved the cyclability of a Li/LiFePO4 cell. For the Li/LiFePO4 half-cells, after 20 cycles at room temperature at 0.1 C, the discharge capacity was 109.7 mAh g?1 with 98.7% capacity retention in the [MMOCPip][TFSI]/0.1 M LiTFSI electrolyte. The good electrochemical performance demonstrated that the [MMOCPip][TFSI] could be used as electrolyte for lithium-ion batteries.  相似文献   

11.
Hexagonal β-Ni(OH)2 nanosheets with thickness of ~12 nm were synthesized by a hydrothermal method at 150 °C using nickel chloride as nickel source and morpholine as alkaline. Electrodes for application in pseudocapacitor were assembled through a traditional technique: pressing a mixture of β-Ni(OH)2 nanosheets and acetylene black onto nickel foam. Due to the hexagonal shape of rigid β-Ni(OH)2 nanosheet and the mediation of surface-modified glycerol during electrochemical charge–discharge cycles, a nanostructure of electrode material with facile interior pathway for the transfer of electrolyte was formed. As a result, the as-formed electrodes presented high specific capacitance of 1,917 F g?1 at current density of 1.6 A g?1 in 3 mol L?1 KOH solution. At high charge and discharge current density of 31.3 A g?1, the electrodes still remained a high specific capacitance of 1,289 F g?1. The interesting results obtained from this investigation may provide a new insight for the synthesis of electrode materials with high electrochemical performance.  相似文献   

12.
In this work, Li2ZrF6, a lithium salt additive, is reported to improve the interface stability of LiNi0.5Mn1.5O4 (LNMO)/electrolyte interface under high voltage (4.9 V vs Li/Li+). Li2ZrF6 is an effective additive to serve as an in situ surface coating material for high-voltage LNMO half cells. A protective SEI layer is formed on the electrode surface due to the involvement of Li2ZrF6 during the formation of SEI layer. Charge/discharge tests show that 0.15 mol L?1 Li2ZrF6 is the optimal concentration for the LiNi0.5Mn1.5O4 electrode and it can improve the cycling performance and rate property of LNMO/Li half cells. The results obtained by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) demonstrate that Li2ZrF6 can facilitate the formation of a thin, uniform, and stable solid electrolyte interface (SEI) layer. This layer inhibits the oxidation decomposition of the electrolyte and suppresses the dissolution of the cathode materials, resulting in improved electrochemical performances.  相似文献   

13.
To determine the effect of electrolyte salts on the cycling properties of tin anodes in sodium ion batteries, sodium/tin cells were prepared using eight electrolytes containing NaCF3SO3, NaBF4, NaClO4, and NaPF6 in ethylene carbonate-dimethyl carbonate (EC-DMC) and EC-DMC/fluoroethylene carbonate (FEC) solvents. The first charge capacity and cycling properties strongly depended on the electrolyte salts. Additionally, an appropriately chosen electrolyte salt in combination with the FEC additive improved the cycling properties of the tin electrode. The tin electrode in the presence of the FEC-containing NaPF6-based electrolyte exhibited the best cycling properties. The first charge capacity and charge capacity after the 45th cycle were 220 and 189 mAh g?1 electrode, respectively at a current density of 84.7 mA g?1 electrode. The rate performance is also studied using the optimized electrolyte which reveals the ability of the electrode to perform in high current application. At a high current density of 4235 mA g?1 electrode, the capacity delivered is 24 mAh g?1 electrode. At a current rate of 1694 mA g?1 electrode, at the end of 1400th cycle, capacity is about 45 mAh g?1 electrode. The results of the study clearly indicate that the electrolyte salts critically affect the electrochemical performance of the tin anode in sodium ion batteries.  相似文献   

14.
Photoelectrochemical properties of FTO/BiVO4 electrode were investigated in different electrolytic solutions, potassium chloride (KCl) and sodium sulphate (Na2SO4), and under visible light irradiation condition. In order to accomplish that, an FTO/BiVO4 electrode was built by combining the solution combustion synthesis technique with the dip-coating deposition process. The morphology and structure of the BiVO4 electrode were investigated through X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and Raman spectroscopy. Photoelectrochemical properties were analyzed through chronoamperometry measurements. Results have shown that the FTO/BiVO4 electrode presents higher electroactivity in the electrolyte Na2SO4, leading to better current stabilization, response time, and photoinduced current density, when compared to KCl electrolyte. Besides, this electrode shows excellent performance for methylene blue degradation under visible light irradiation condition. In Na2SO4, the electrode has shown higher degradation rate, 51 %, in contrast to 44 % in KCl, plus higher rate constant, 174?×?10?4 min?1 compared to 150?×?10?4 min?1 in KCl. Results presented in this communication leads to the indication of BiVO4 thin films as alternate materials to use in heterogeneous photoelectrocatalysis, more specifically in decontamination of surface water.  相似文献   

15.
Wei Sun  Jun Liu  Xiaomei Ju  Le Zhang  Xiaowei Qi  Ni Hui 《Ionics》2013,19(4):657-663
A new electrochemical method for the sensitive detection of adenine was established on a chitosan (CTS)- and graphene (GR)-modified carbon ionic liquid electrode (CILE). CILE was prepared by mixing 1-butylpyridinium hexafluorophosphate (BPPF6) and paraffin with graphite powder. Due to the synergistic effects of GR, CILE, and the interaction of GR with IL on the electrode surface, the electrochemical performance of CTS/GR/CILE were greatly enhanced. Electrochemical behaviors of adenine on the modified electrode was investigated with a single well-defined oxidation peak appeared. The electrochemical reaction of adenine was an adsorption-controlled irreversible process, and the electrochemical parameters were further calculated. Under the optimal conditions, the oxidation peak current was proportional to adenine concentration in the range from 1.0 nmol L?1 to 70.0 μmol L?1 with a detection limit of 0.286 nmol L?1 (3σ) by differential pulse voltammetry. The established method showed the advantages such as good selectivity, stability, and repeatability.  相似文献   

16.
Cyclic voltammetry, galvanostatic charge?Cdischarge technique, potentiostatic intermittent titration technique (PITT), and electrochemical impedance spectroscopy (EIS) were used to study the behavior of a LiMn1.95Cr0.05O4 (substituted lithium?Cmanganese spinel) electrode in nonaqueous electrolytes at 25 °C. Quantitative and qualitative changes of the electrode transport parameters as functions of lithium concentration were analyzed. Several equivalent circuits are discussed; the results obtained by different methods are compared. The PITT and EIS results are in good agreement; the chemical diffusion coefficient D varies within 10?14?C10?9 cm2 s?1 depending on the lithium content in the LixMn1.95Cr0.05O4 electrode.  相似文献   

17.
Lithium bis(oxalate)borate (LiBOB) is a promising salt for lithium-ion batteries. However, it is necessary to exert the electrochemical performance of LiBOB by the appropriate solvent. With dimethyl sulfite (DMS) as mixed solvents, the electrochemical behavior of γ-butyrolactone (GBL) with LiBOB is studied in this paper. It shows that LiBOB-GBL/DMS electrolyte has high oxidation potential (>5.3 V) and satisfactory conductivities. When used in lithium and mesophase carbon microbead cells, the novel electrolyte exhibits not only excellent film-forming characteristics but also low impedances of the interface films. Besides, when used in LiFeO4/Li cells, compared to the cell with the electrolyte system of 1 mol L?1 LiPF6–ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1, v/v), LiBOB-based electrolyte exhibits several advantages, such as more stable cycle performance at room temperature and higher mean voltage.  相似文献   

18.
Al-doped ZnO (AZO) was sputtered on the surface of LiNi1/3Co1/3Mn1/3O2 (NCM) thin film electrode via radio frequency magnetron sputtering, which was demonstrated to be a useful approach to enhance electrochemical performance of thin film electrode. The structure and morphology of the prepared electrodes were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectrometer, and transmission electron microscopy techniques. The results clearly demonstrated that NCM thin film showed a strong (104) preferred orientation and AZO was uniformly covered on the surface of NCM electrode. After 200 cycles at 50 μA μm?1 cm?2, the NCM/AZO-60s electrode delivered highest discharge capacity (78.1 μAh μm?1 cm?2) compared with that of the NCM/AZO-120s electrode (62.4 μAh μm?1 cm?2) and the bare NCM electrode (22.3 μAh μm?1 cm?2). In addition, the rate capability of the NCM/AZO-60s electrode was superior to the NCM/AZO-120s and bare NCM electrodes. The improved electrochemical performance can be ascribed to the appropriate thickness of the AZO coating layer, which not only acted as HF scavenger to keep a stable electrode/electrolyte interface but also reduced the charge transfer resistance during cycling.  相似文献   

19.
The present work was performed in order to evaluate sulfamic acid as the supporting electrolyte for VO2+/VO2 + redox couple in vanadium redox flow battery. The oxidation process of VO2+ has similar electrochemical kinetics compared with the reduction process of VO2 +. The exchange current density and standard rate constant of VO2+/VO2 + redox reaction on a graphite electrode in sulfamic acid are determined as 7.6?×?10?4 A cm?2 and 7.9?×?10?5 cm s?1, respectively. The energy efficiency of the cell employing sulfamic acid as supporting electrolyte in the positive side can reach 75.87 %, which is adequate for redox flow battery applied in energy storage. The addition of NH4 + to the positive electrolyte can enhance the electrochemical performance of the cell, with larger discharge capacity and energy efficiency. The preliminary exploration shows that the vanadium sulfamate electrolyte is promising for vanadium redox flow battery and is worthy of further study.  相似文献   

20.
A new copolymer, poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)), was synthesized by emulsion polymerization with different mass ratio of methyl methacrylate (MMA) and butyl acrylate (BA). The membranes were prepared by phase inversion and corresponding gel polymer electrolytes (GPEs) were obtained by immersing the membrane into a liquid electrolyte. In this design, the hard monomer MMA provided the copolymer with good electrolyte uptake, while the soft monomer BA provided the GPE with strong adhesion between the anode and cathode of lithium ion battery. The properties of the resulting product were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectra, scanning electron spectroscopy, linear sweep voltammetry, thermogravimetric analysis, cyclic voltammetry, electrochemical impedance spectroscopy and charge/discharge test. The results show that the obtained GPE based on P(MMA-co-BA) with the mass ratios of MMA and BA = 6:1 exhibits good conductivity (as high as 1.2 × 10?3 S cm?1) at room temperature and high electrochemical stability (up to 4.9 V vs. Li/Li+). With the application of the polyethylene (PE)-supported GPE in Li/Li(Li0.13Ni0.30Mn0.57)O2 battery, the battery presents good cyclic stability (maintaining 95.4 % of its initial discharge capacity after 50 cycles) at room temperature.  相似文献   

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