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1.
Mesopore nickel-based mixed rare-earth oxide (NMRO) and activated carbon (AC) with rich oxygen-contained groups were prepared as electrode materials in a supercapacitor using room temperature ionic liquid (RTIL) electrolyte. These electrode materials were characterized by XPS, XRD, N2 adsorption, SEM as well as various electrochemical techniques, and showed good properties and operated well with RTIL electrolyte. A 3 V asymmetrical supercapacitor was fabricated, which delivered a real power density of 458 W kg−1 as well as a real energy density of 50 Wh kg−1, and during a 500-cycle galvanostatic charge/discharge measurement, no capacity decay was visible. Such promising energy-storage performance was to a large extent ascribed to nonvolatile RTIL electrolyte with wide electrochemical windows and high stable abilities worked with both electrode materials.  相似文献   

2.
Electrochemical intercalation of lithium into a natural graphite anode was investigated in electrolytes based on a room temperature ionic liquid consisting of trimethyl-n-hexylammonium (TMHA) cation and bis(trifluoromethanesulfone) imide (TFSI) anion. Graphite electrode was less prone to forming effective passivation film in 1 M LiTFSI/TMHA-TFSI ionic electrolyte. Reversible intercalation/de-intercalation of TMHA cations into/from the graphene interlayer was confirmed by using cyclic voltammetry, galvanostatic measurements, and ex situ X-ray diffraction technique. Addition of 20 vol% chloroethylenene carbonate (Cl-EC), ethylene carbonate (EC), vinyl carbonate (VC), or ethylene sulfite (ES) into the ionic electrolyte resulted in the formation of solid electrolyte interface (SEI) film prior to TMHA intercalation and allowed the formation of Li-C6 graphite interlayer compound. In the ionic electrolyte containing 20 vol% Cl-EC, the natural graphite anode exhibited excellent electrochemical behavior with 352.9 mAh/g discharge capacity and 87.1% coulombic efficiency at the first cycle. A stable reversible capacity of around 360 mAh/g was obtained in the initial 20 cycles without any noticeable capacity loss. Mechanisms concerning the significant electrochemical improvement of the graphite anode were discussed. Ac impedance and SEM studies demonstrated the formation of a thin, homogenous, compact and more conductive SEI layer on the graphite electrode surface.  相似文献   

3.
利用静电纺丝技术制备了聚吲哚/聚丙烯腈(PIN/PAN)聚合物基电解质膜,代替纸基铝空气电池中的纤维素纸(C-P),并应用于固态铝空气电池。探究了PIN含量对电解质膜离子电导率及吸液率的影响。采用SEM和FTIR对PIN/PAN聚合物基电解质膜表面形貌及化学组成进行分析。借助电化学工作站和电池测试系统,分析了电解质膜离子电导率及固态铝空气电池放电特性。结果表明,采用PIN/PAN聚合物基电解质膜可有效提升固态铝空气电池性能,在3 mA.cm-2、5 mA.cm-2、7 mA.cm-2电流密度下,放电时长比纸基铝空气电池分别提升了21%、27%、34%,且放电时长与电解质膜的吸液率及离子电导率相关。其中4%PIN/PAN聚合物基电解质膜离子电导率可达6.7×10-4 S.cm-1,同时对碱性溶液具有良好的吸附能力,吸液率最高可达496%,为纤维素纸的3.2倍。  相似文献   

4.
Rechargeable lithium/sulfur battery with suitable mixed liquid electrolytes   总被引:1,自引:0,他引:1  
The suitability of some single/binary liquid electrolytes and polymer electrolytes with a 1 M solution of LiCF3SO3 was evaluated for discharge capacity and cycle performance of Li/S cells at room temperature. The liquid electrolyte content in the cell was found to have a profound influence on the first discharge capacity and cycle property. The optimum, stable cycle performance at about 450 mAh g−1 was obtained with a medium content (12 μl) of electrolyte. Comparison of cycle performance of cells with tetra(ethylene glycol)dimethyl ether (TEGDME), TEGDME/1,3-dioxolane (DIOX) (1:1, v/v) and 1,2-dimethoxyethane (DME)/di(ethylene glycol)dimethyl ether (DEGDME) (1:1, v/v) showed better results with the mixed electrolytes based on TEGDME. The addition of 5 vol.% of toluene in TEGDME had a remarkable effect of increasing the initial discharge capacity from 386 to 736 mAh g−1 (by >90%) and stabilizing the cycle properties, attributed to the reduced lithium metal interfacial resistance obtained for the system. Polymer electrolyte based on microporous poly(vinylidene fluoride) (PVdF) membrane and TEGDME/DIOX was evaluated for ionic conductivity at room temperature, lithium metal interfacial resistance and cycle performance in room-temperature Li/S cells. A comparison of the liquid electrolyte and polymer electrolyte showed a better performance of the former.  相似文献   

5.
Several 1-alkyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ionic liquids (alkyl-DMimTFSI) were prepared by changing carbon chain lengths and configuration of the alkyl group, and their electrochemical properties and compatibility with Li/LiFePO4 battery electrodes were investigated in detail. Experiments indicated the type of ionic liquid has a wide electrochemical window (−0.16 to 5.2 V vs. Li+/Li) and are theoretically feasible as an electrolyte for batteries with metallic lithium as anode. Addition of vinylene carbonate (VC) improves the compatibility of alkyl-DMimTFSI-based electrolytes towards lithium anode and LiFePO4 cathode, and enhanced the formation of solid electrolyte interface to protect lithium anodes from corrosion. The electrochemical properties of the ionic liquids obviously depend on carbon chain length and configuration of the alkyl, including ionic conductivity, viscosity, and charge/discharge capacity etc. Among five alkyl-DMimTFSI-LiTFSI-VC electrolytes, Li/LiFePO4 battery with the electrolyte-based on amyl-DMimTFSI shows best charge/discharge capacity and reversibility due to relatively high conductivity and low viscosity, its initial discharge capacity is about 152.6 mAh g−1, which the value is near to theoretical specific capacity (170 mAh g−1). Although the battery with electrolyte-based isooctyl-DMimTFSI has lowest initial discharge capacity (8.1 mAh g−1) due to relatively poor conductivity and high viscosity, the value will be dramatically added to 129.6 mAh g−1 when 10% propylene carbonate was introduced into the ternary electrolyte as diluent. These results clearly indicates this type of ionic liquids have fine application prospect for lithium batteries as highly safety electrolytes in the future.  相似文献   

6.
Chi-Lin Li 《Electrochimica acta》2008,53(12):4293-4301
Nano-sized CuWO4 thin films have been fabricated by radio-frequency (R.F.) sputtering deposition, and are used as positive electrode with both LiClO4 liquid electrolyte and LiPON solid electrolyte in rechargeable lithium batteries. An initial discharge capacity of 192 and 210 mAh/g is obtainable for CuWO4 film electrode with and without coated LiPON in liquid electrolyte, respectively. An all-solid-state cell with Li/LiPON/CuWO4 layers shows a high-volume rate capacity of 145 μAh/cm2 μm in first discharge, and overcomes the unfavorable electrochemical degradation observed in liquid electrolyte system. A two-step reactive mechanism is investigated by both transmission electron microscopy and selected area electron diffraction techniques. Apart from the extrusion and injection of Cu2+/Cu0, additional capacity can be achieved by the reversible reactivity of (WO4)2− framework. The chemical diffusion coefficients of Li intercalation/deintercalation are estimated by cyclic voltammetry. Nano-CuWO4 thin film is expected to be a promising positive electrode material for high-performance rechargeable thin-film lithium batteries.  相似文献   

7.
The effects of ionic liquid (IL) N-methyl-N-butylpyrrolidinium bis(trifluoromethylsulfonyl)imide (Py14TFSI) based electrolyte on the electrochemical performance of cathode material Li[Li0.2Mn0.54Ni0.13Co0.13]O2 have been investigated. The results of thermogravimetric analysis (TGA), flammability and differential scanning calorimetry (DSC) tests indicate that Py14TFSI addition enhances thermal stability of the electrolyte and reduces the safety concern of Li-ion battery. Electrochemical measurements demonstrate that the cathode material shows good electrochemical performance in Py14TFSI-added electrolyte. The cathode material is able to deliver high initial discharge capacity of 250 mAh g?1 in electrolyte with Py14TFSI content up to 80% at 0.1 C. In addition, the cathode material delivers less initial irreversible capacity loss and higher initial coulombic efficiency in electrolyte with higher Py14TFSI content. However, increasing Py14TFSI content in the electrolyte affects rate capability of the cathode material distinctively. With 60% Py14TFSI-added electrolyte, Li[Li0.2Mn0.54Ni0.13Co0.13]O2 shows better cycling stability with a capacity retention of 84.4% after 150 cycles at 1.0 C than that in IL free electrolyte. The superior cycling performance of the cathode material cycled in Py14TFSI-added electrolyte is mainly ascribed to the formation of stable electrode/electrolyte interfaces, based on the results of scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS) and electrochemical impedance spectroscopy (EIS) investigations.  相似文献   

8.
M. Holzapfel  C. Jost  F. Krumeich  H. Buqa 《Carbon》2005,43(7):1488-1498
1-Ethyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide (EMI-TFSI) is shown to reversibly permit lithium intercalation into standard TIMREX® SFG44 graphite when vinylene carbonate (VC) is used in small amounts as additive. The best performance was obtained when 5% of VC was added to a 1 M solution of LiPF6 in EMI-TFSI. Intercalation of lithium in the SFG44 graphite host was demonstrated over 100 cycles without noticeable capacity fading. The reversible charge capacity was around 350 mA h g−1 and an only small irreversible capacity loss per cycle could be observed. Li4Ti5O12 was used as counter electrode material. Scanning electron microscopy indicates the reduction of the electrolyte without graphite exfoliation in the neat electrolyte and the formation of a passivation film in the case of a VC-containing electrolyte. Other additives that were tested comprise ethylene sulphite and acrylonitrile which show also a positive effect, but a smaller one than vinylene carbonate. LiCoO2 positive electrodes were cycled in a 1 M solution of LiPF6 in EMI-TFSI with good charge capacity retention over more than 300 cycles, when Li4Ti5O12 was used as counter electrode. The formation of a passivation film is proven on the LiCoO2-electrodes, when the electrolyte contained VC, but not in the neat ionic liquid. Finally, the stable cycling of a full cell configuration is proven in this electrolyte system. An ammonium-containing ionic liquid (methyltrioctylammonium-bis(trifluoromethylsulfonyl)-imide, MTO-TFSI) is shown to permit the cycling of both, graphite and lithium cobalt oxide when VC is used as additive in small amounts, but at slightly elevated temperatures.  相似文献   

9.
A novel gel polymer electrolyte (GPE) which is based on new synthesized boron‐containing monomer, benzyl methacrylate, 1 m LiClO4/N,N‐dimethylformamidel liquid electrolyte solution is prepared through a one‐step synthesis method. The boron‐containing GPE (B‐GPE) not only displays excellent mechanical behavior, favorable thermal stability, but also exhibits an outstanding ionic conductivity of 2.33 mS cm?1 at room temperature owing to the presence of anion‐trapping boron sites. The lithium ion transference in this gel polymer film at ambient temperature is 0.60. Furthermore, the symmetrical supercapacitor which is fabricated with B‐GPE as electrolyte and reduced graphene oxide as electrode demonstrates a broad potential window of 2.3 V. The specific capacitance of symmetrical B‐GPE supercapacitors retains 90% after 3000 charge–discharge cycles at current density of 1 A g?1.  相似文献   

10.
Gel polymer electrolyte (GPE) was prepared using polyurethane acrylate as polymer host and its performance was evaluated. LiCoO2/GPE/graphite cells were prepared and their electrochemical performance as a function of discharge currents and temperatures was evaluated. The precursor containing a 5 vol % curable mixture had a viscosity of 4.5 mPa s. The ionic conductivity of the GPE at 20 °C was about 4.5 × 10–3 S cm–1. The GPE was stable electrochemically up to a potential of 4.8 V vs Li/Li+. LiCoO2/GPE/graphite cells showed a good high rate and low-temperature performance. The discharge capacity of the cell was stable with charge–discharge cycling.  相似文献   

11.
The poly(propylene carbonate maleate) (PPCMA) was synthesized by the terpolymerization of carbon dioxide, propylene oxide, and maleic anhydride. The PPCMA polymer can be readily crosslinked using dicumyl peroxide (DCP) as crosslinking agent and then actived by absorbing liquid electrolyte to fabricate a novel PPCMA gel polymer electrolyte for lithium‐ion battery. The thermal performance, electrolyte uptake, swelling ratio, ionic conductivity, and lithium ion transference number of the crosslinked PPCMA were then investigated. The results show that the Tg and the thermal stability increase, but the absorbing and swelling rates decrease with increasing DCP amount. The ionic conductivity of the PPCMA gel polymer electrolyte firstly increases and then decreases with increasing DCP ratio. The ionic conductivity of the PPCMA gel polymer electrolyte with 1.2 wt % of DCP reaches the maximum value of 8.43 × 10−3 S cm−1 at room temperature and 1.42 × 10−2 S cm−1 at 50°C. The lithium ion transference number of PPCMA gel polymer electrolyte is 0.42. The charge/discharge tests of the Li/PPCMA GPE/LiNi1/3Co1/3Mn1/3O2 cell were evaluated at a current rate of 0.1C and in voltage range of 2.8–4.2 V at room temperature. The results show that the initial discharge capacity of Li/PPCMA GPE/LiNi1/3Co1/3Mn1/3 O2 cell is 115.3 mAh g−1. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010  相似文献   

12.
We reported a composite electrolyte prepared by incorporating layered α-titanium phosphate (α-TiP) into an iodide-based electrolyte using 1-ethyl-3-methylimidazolium tetrafluoroborate(EmimBF4) ionic liquid as solvent. The obtained composite electrolyte exhibited excellent electrochemical and photovoltaic properties compared to pure ionic liquid electrolyte. Both the diffusion coefficient of triiodide (I3 ) in the electrolyte and the charge-transfer reaction at the electrode/electrolyte interface were improved markedly. The mechanism for the enhanced electrochemical properties of the composite electrolyte was discussed. The highest conversion efficiency of dye-sensitized solar cell (DSSC) was obtained for the composite electrolyte containing 1wt% α-TiP, with an improvement of 58% in the conversion efficiency than the blank one, which offered a broad prospect for the fabrication of stable DSSCs with a high conversion efficiency.  相似文献   

13.
Lithium vanadium fluorophosphate, LiVPO4F, was utilized as both cathode and anode for fabrication of a symmetric lithium-ion LiVPO4F//LiVPO4F cell. The electrochemical evolution of the LiVPO4F//LiVPO4F cell with the commonly used organic electrolyte LiPF6/EC-DMC has shown that this cell works as a secondary battery, but exhibits poor durability at room temperature and absolutely does not work at increased operating temperatures. To improve the performance and safety of this symmetric battery, we substituted a non-flammable ionic liquid (IL) LiBF4/EMIBF4 electrolyte for the organic electrolyte. The symmetric battery using the IL electrolyte was examined galvanostatically at different rates and operating temperatures within the voltage range of 0.01–2.8 V. It was demonstrated that the IL-based symmetric cell worked as a secondary battery with a Coulombic efficiency of 77% at 0.1 mA cm−2 and 25 °C. It was also found that the use of the IL electrolyte instead of the organic one resulted in the general reduction of the first discharge capacity by about 20–25% but provided much more stable behavior and a longer cycle life. Moreover, an increase of the discharge capacity of the IL-based symmetric battery up to 120 mA h g−1 was observed when the operating temperature was increased up to 80 °C at 0.1 mA cm−2. The obtained electrochemical behavior of both symmetric batteries was confirmed by complex-impedance measurements at different temperatures and cycling states. The thermal stability of LiVPO4F with both the IL and organic electrolytes was also examined.  相似文献   

14.
A polyterthiophene (PTTh)/multi-walled carbon nanotube (CNT) composite was synthesised by in situ chemical polymerisation and used as an active cathode material in lithium cells assembled with an ionic liquid (IL) or conventional liquid electrolyte, LiBF4/EC-DMC-DEC. The IL electrolyte consisted of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIBF4) containing LiBF4 and a small amount of vinylene carbonate (VC). The lithium cells were characterised by cyclic voltammetry (CV) and galvanostatic charge/discharge cycling. The specific capacity of the cells with IL and conventional liquid electrolytes after the 1st cycle was 50 and 47 mAh g−1 (based on PTTh weight), respectively at the C/5 rate. The capacity retention after the 100th cycle was 78% and 53%, respectively. The lithium cell assembled with a PTTh/CNT composite cathode and a non-flammable IL electrolyte exhibited a mean discharge voltage of 3.8 V vs Li+/Li and is a promising candidate for high-voltage power sources with enhanced safety.  相似文献   

15.
Well-defined star shaped polymers with α-Cyclodextrin (α-CD) core linking PMMA-block arms were synthesized by atom transfer radical polymerization (ATRP). Gel polymer electrolytes (GPEs) were prepared by encapsulating electrolyte solution of 1 mol L−1 of LiClO4/EC-PC (volume 1:1) into the obtained star shaped polymer host. The ionic conductivity of the GPEs and the cycling characteristics of LiCoO2/GPEs/Graphite cell were studied by electrochemical impedance spectroscopy and charge-discharge testing, respectively. The results indicate that the GPEs have a high ionic conductivity up to 1.63 × 10−3 S cm−1 at room temperature and exhibit a high electrochemical stability potential of 4.5 V (vs. Li/Li+). The discharge capacity of LiCoO2/GPEs/Graphite cell is about 98% of its initial discharge capacity after 20 cycles at 0.1 C rate. Discharge capacity of the model cell with GPEs is stable with charge-discharge cycling.  相似文献   

16.
Polymerized ionic liquids (PILs) having guanidinium cations with different counter‐anions, such as PF6? and N(CF3SO2)2? (TFSI?), were synthesized by copolymerization of a guanidinium ionic liquid monomer with methyl acrylate followed by an anion exchange reaction. Furthermore, incorporating a guanidinium ionic liquid, LiTFSI salt and nano‐size SiO2, a quaternary gel polymer electrolyte based on one of the PILs as the polymer host was prepared. The quaternary gel polymer electrolyte was chemically stable even at a higher temperature of 80 °C in contact with the lithium anode. In particular, the electrolyte exhibited high lithium ion conductivity, wide electrochemical stability window and good lithium stripping/plating performance. Li/LiFePO4 batteries with the quaternary gel polymer electrolyte at 80 °C had capacities of 140 and 130 mA h g?1 respectively at 0.1 and 0.2 C current rates. Copyright © 2011 Society of Chemical Industry  相似文献   

17.
Nanoscale TiO2 particle filled poly(vinylidenefluoride-co-hexafluoropropylene) film is characterized by investigating some properties such as surface morphology, thermal and crystalline properties, swelling behavior after absorbing electrolyte solution, chemical and electrochemical stabilities, ionic conductivity, and compatibility with lithium electrode. Decent self-supporting polymer electrolyte film can be obtained at the range of <50 wt% TiO2. Different optimal TiO2 contents showing maximum liquid uptake may exist by adopting other electrolyte solution. Room temperature ionic conductivity of the polymer electrolyte placed surely on the region of >10−3 S/cm, and thus the film is very applicable to rechargeable lithium batteries. An emphasis is also be paid on that much lower interfacial resistance between the polymer electrolyte and lithium metal electrode can be obtained by the solid-solvent role of nanoscale TiO2 filler.  相似文献   

18.
The modified polypropylene (PP) separators with self‐polymerization of dopamine on the surfaces are prepared by a simple solution‐immersion method to improve the interfacial hydrophilic and discharge performance. The contact angle test and the liquid electrolyte uptake capacity test results show that the wettability and the electrolyte‐retention ability of polydopamine‐modified separator are improved significantly. The robust and thin polydopamine layer on the surface also enhances thermal performance and tensile strength of the modified PP separator certified by DSC and tensile strength tests. The ionic conductivity of the modified PP separator is up to 3.08 mS·cm?1, ~2.5 times of the bare separator. Good discharge capacity retention and C‐rate discharge performance are demonstrated by a 2025 coin half‐cell with the liquid electrolyte‐soaked polydopamine modified PP separator sandwiched between lithium metal anode and LiFePO4 cathode. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40543.  相似文献   

19.
An admixture of commercial liquid electrolyte (LB302, 1 M solution of LiPF6 in 1:1 EC/DEC) and methyl methacrylate (MMA) was enclosed in CR2032 cells. The assembled cells were then -ray-irradiated using configurations of half cells and full cells. Through this in situ irradiation polymerization process, we obtained rechargeable lithium ion cells with poly(methyl methacrylate) (PMMA) based gel polymer electrolytes (GPE). Galvanostatic cycling, AC impedance spectroscopy, and cyclic voltammetry were employed to investigate the electrochemical properties of the cells and the gel polymer electrolyte. This PMMA-based gel polymer electrolyte was found to exhibit a high ionic conductivity (at least 10–3 S cm–1) at room temperature. Due to a significant increase in the charge transfer resistance between the GPE and the cathode, the cell impedance of a PMMA-based lithium ion cell is greater than that of a liquid-electrolyte-based cell. The discharge capacity of a LiNi0.8Co0.2O2/GPE/graphite is approximately 145 mAh g–1 for the first cycle and decreases to123 mAh g–1 after 20 cycles. In addition, a large initial cell impedance (LICI) was observed in the irradiated positive half cell. In this paper, we propose a possible mechanism related to the detachment of the PMMA layer from the lithium electrode. This detachment of the PMMA layer from the lithium electrode has not been explicitly discussed previously.  相似文献   

20.
In order to improve the discharge capacity in lithium ion microbatteries, a thick-film cathode was fabricated by a screen printing using LiCoO2 pastes. The printed cathode showed a different discharge curves when the cell was tested using various (liquid, gel and solid-state) electrolytes. When a cell test was performed with organic liquid electrolyte, the maximum discharge capacity was 200 μAh cm−2, which corresponded to approximately 133 mAh g−1 when the loading weight of LiCoO2 was calculated. An all-solid-state microbattery could be assembled using sputtered LiPON electrolyte, an evaporated Li anode, and printed LiCoO2 cathode films without delamination or electrical problems. However, the highest discharge capacity showed a very small value (7 μAh cm−2). This problem could be improved using a poly(vinylidene fluoride-hexafluoro propylene) (PVDF-HFP) gel electrolyte, which enhanced the contact area and adhesion force between cathode and electrolyte. The discharge value of this cell was measured as approximately 164 μAh cm−2 (≈110 mAh g−1). As the PVDF-HFP electrolyte had a relatively soft contact property with higher ionic conductance, the cell performance was improved. In addition, the cell can be fabricated in a leakage-free process, which can resolve many safety problems. According to these results, there is a significant possibility that a film prepared using the aforementioned paste with screen printing and PVDF-HFP gel electrolyte is feasible for a microbattery.  相似文献   

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