Showing papers in "ECS Electrochemistry Letters in 2012"
TL;DR: In this article, a copper rubeanate metal organic framework (CR-MOF) was used to improve the catalytic activity of electrochemical reduction of CO2 due to its characteristics of electronic conductivity, proton conductivity and dispersed reaction sites, and nanopores.
Abstract: We synthesized a copper rubeanate metal organic framework (CR-MOF) which has the potential to improve the catalytic activity of electrochemical reduction of CO2 due to its characteristics of electronic conductivity, proton conductivity, dispersed reaction sites, and nanopores. Synthesized CR-MOF particles were dropped on carbon paper (CP) to form a working electrode. The onset potential for CO2 reduction of a CR-MOF electrode was about 0.2 V more positive than that observed on a Cu metal electrode in an aqueous electrolyte solution. Our analysis of the reduction products during potentiostatic electrolysis showed formic acid (HCOOH) to be virtually the only CO2 reduction product on a CR-MOF electrode, whereas a Cu metal electrode generates a range of products. The quantity of products from the CR-MOF electrode was markedly greater (13-fold at −1.2 V vs. SHE) than that of a Cu metal electrode. Its stability was also confirmed.
167 citations
TL;DR: In this paper, the corrosion behavior of aluminum current collectors at high potentials in the presence of the electrolyte salt LiN(SO2CF3)2 and various electrolyte solvents is studied.
Abstract: The corrosion behavior of aluminum current collectors at high potentials in the presence of the electrolyte salt LiN(SO2CF3)2 and various electrolyte solvents is studied. The corrosion is investigated, by detection of the actual weight loss of the current collector. Collector corrosion depends on the chemistry of the electrolyte solvent, with strong corrosion in the presence of carbonates and lactones and minimal corrosion in the presence of nitriles. It is demonstrated that not only a charge consuming aluminum dissolution takes place and possible explanations are discussed.
113 citations
TL;DR: In this paper, the authors applied polyacrylic acid (PAA) as a binder in the aqueous solvent in the preparation of sulfur cathode for lithium-sulfur battery.
Abstract: Polyacrylic acid (PAA) as a binder in the aqueous solvent is applied in the preparation of sulfur cathode for lithium-sulfur battery. Electrochemical performances are investigated by a charge-discharge cycle test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV and EIS tests indicate that the PAA sulfur cathode has smaller resistance and better kinetics characteristics than that of the poly(vinylidene fluoride) (PVDF) sulfur cathode using PVDF as a binder in N-methy-2-pyrrolidone (NMP) solvent. The charge-discharge tests show that the discharge capacity and the coulombic efficiency of the PAA sulfur cathode are 325 mAh g −1 and 89.5% at the 50th cycle at the current density of 335 mA g −1 . Compared with the PVDF sulfur cathode, the PAA sulfur cathode shows considerably a better cyclability. These results show that the PAA binder has great potential for lithium-sulfur battery applications.
100 citations
TL;DR: In this article, the electrochemical properties of Mg2Si in dilute NaCl over a range of pH values are presented, revealing that Mg 2Si is either a local anode or local cathode.
Abstract: The electrochemical characteristics of Mg2Si in dilute NaCl over a range of pH values are presented. In this study, Mg2Si was carefully synthesized to permit the collection of its anodic and cathodic potentiodynamic polarization response. Difficulties in producing bulk Mg2Si means that such data remains scarce to date. Mg2Si is an important intermetallic that forms in Al and Mg alloys containing silicon. In this work, the electrochemical response of Mg2Si is interpreted (and contrasted) in the context of Al and Mg alloys that contain Mg2Si, revealing that Mg2Si is either a local anode or local cathode.
88 citations
TL;DR: In this paper, a 30 mL sample bottle containing 10 mL of candidate solvent with/without 1 M of supporting electrolyte, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, Kanto Chemical, >99.7%), and the bottle was closed and placed 24 hours in room temperature.
Abstract: Candidate solvents which we examined were PC (Kishida chemical, >99.5%), dimethylsulfoxide (DMSO, Wako pure chemical, >99%), acetonitrile (ACN, Wako pure chemical, >99%), 3-methoxypropionitrile (MPN, Wako pure chemical, >99%), trimethyl phosphate (TMP, Wako pure chemical, >99%), sulfolane (SULF, Aldrich, >99%), tetramethylene sulfoxide (TMSO, Aldrich, >99%), tetraglyme (TGly, Aldrich, >99%) and ionic liquid, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (PP13-TFSI, Kanto Chemical), and these solvents were used as received without further purification. 0.2 g (2.8 mmol) of yellow KO2 powder (Strem chemicals, 96.5%) was slowly added into 30 mL sample bottle containing 10 mL of candidate solvent with/without 1 M of supporting electrolyte, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, Kanto Chemical, >99.7%), and the bottle was closed and placed 24 hours in room temperature. Precipitates were filtrated by separable syringe filter (1 μm pore) and washed in DMSO and chloroform three times, respectively. After drying in vacuum, the precipitates were analyzed by Raman and IR spectroscopy. The yields of the precipitates were in the range of 50‐130 wt% as compared with the weight of added KO2. All process and analysis were carried out under inert gas (Ar) atmosphere. Analytical method of Raman and IR were identical of our previous report. 13 Baseline calibration of
70 citations
59 citations
TL;DR: In this article, the strontium effect in PrBa1-xSrxCo2O5+δ oxides was investigated based on their structural characteristics, electrical properties, and electrochemical performance.
Abstract: The strontium effect in PrBa1–xSrxCo2O5+δ (x = 0, 0.25, 0.5, 0.75, and 1.0) oxides was investigated based on their structural characteristics, electrical properties, and electrochemical performance. Electrical conductivities increase with increasing strontium content due to the higher oxygen content and coordination number. The area specific resistance (ASR) of PrBa1–xSrxCo2O5+δ were measured on Ce0.9Gd0.1O1.95 (GDC) and the minimum ASR values were observed at x = 0.5 and 0.75. Electrochemical performance of PrBa1–xSrxCo2O5+δ cathodes was measured using Ni-GDC anode-supported cell. The maximum power density was 1.08 W cm −2 at 600 ◦ Cf orx = 0.5 and 0.75.
48 citations
TL;DR: In this paper, the thermal stability of common electrolytes with Li2O2 was investigated and all of the solvents investigated, including ethylene carbonate (EC), propylene carbonates (PC), dialkyl carbonates, dimethoxyethane (DME), tetraethylene glycol dimethyl ether, and acetonitrile, were found to have good thermal stability.
Abstract: The stability of electrolytes is a significant limitation for cycle life performance in Li-O2 batteries. Since Li2O2 is generated at the cathode surface during cycling, an investigation of the thermal stability of common electrolytes with Li2O2 was conducted. All of the solvents investigated, including ethylene carbonate (EC), propylene carbonate (PC), dialkyl carbonates, dimethoxyethane (DME), tetraethylene glycol dimethyl ether, and acetonitrile, have good thermal stability in the presence of Li2O2. Many salts, including LiBF4, lithium bis(oxalaoto)borate (LiBOB), and lithium Bis(trifluoromethanesulfonyl)imide (LiTFSI), also have good stability in the presence of Li2O2. However, LiPF6 reacts rapidly with Li2O2 to generate OPF2OLi and LiF.
40 citations
TL;DR: In this paper, the preparation and electrochemical testing of blended TiS2/sulfur/carbon cathodes in LiSulfur cells is described, and the resulting electrodes are investigated regarding their reversible capacity and degradation behavior.
Abstract: The preparation and electrochemical testing of blended TiS2/sulfur/carbon cathodes in lithium-sulfur cells is described in this paper. TiS2, sulfur and carbon were combined in various ratios and the resulting electrodes were investigated regarding their reversible capacity and degradation behavior in lithium-sulfur cells. The capacity of corresponding cathodes depends on the amount of TiS2 used. The maximum capacity was somewhat lower (compared to sulfur/carbon cathodes) when TiS2 was added, but it was observed that TiS2 improved the pulse power capability of corresponding lithium-sulfur cells.
36 citations
36 citations
TL;DR: In this paper, thylakoid membranes extracted from Spinacia oleracea were physically adsorbed onto Toray paper electrodes with and without catalase, followed by entrapment in a vapor deposited silica matrix.
Abstract: Thylakoid membranes have been proposed for electrochemical solar energy conversion, but they have been plagued with short term instability. In this paper, thylakoid membranes extracted from Spinacia oleracea were physically adsorbed onto Toray paper electrodes with and without catalase, followed by entrapment in a vapor deposited silica matrix. The bioelectrodes were tested using voltammetry and amperometry and tested in a complete photobioelectrochemical cell. Upon subsequent polarization experiments, a significant decrease in the maximum current density from 1.53 ± 0.13 μAcm −2 to 0.75 ± 0.14 μAcm −2 was observed without catalase present. When catalase was included in the anode, this current decrease was not observed, showing the importance of catalase to scavenge reactive oxygen species produced by the thylakoids during photoelectrocatalysis.
TL;DR: Li et al. as discussed by the authors showed that glue-like PAA coating on the electrodes form a protective film, which may protect the LiFePO4 matrix from the corrosive solution or suppress the dissolution of Fe.
Abstract: The electrochemical performance of LiFePO4 at elevated temperature (55°C) is enhanced by using polyacrylic acid (PAA) as a binder. Results show that at 55°C, it can deliver 100 cycles with 97.7% capacity retention and unchanged discharge plateau potential at the current density of 70 mA g−1 (0.5 C), which is much better than the cathode with polyvinylidene fluoride. Scanning electron microscopy studies clearly demonstrate that glue-like PAA coating on the electrodes form a protective film, which may protect the LiFePO4 matrix from the corrosive solution or suppress the dissolution of Fe.
TL;DR: In this article, a new electrolyte additive, methylene methanedisulfonate (MMDS), was used for improving the cycling performance of LiNi0.5Co0.2Mn0.3O2/graphite cells.
Abstract: Methylene methanedisulfonate (MMDS) is evaluated as a new electrolyte additive for improving the cycling performance of the LiNi0.5Co0.2Mn0.3O2/graphite cells cycled in the voltage range of 3.0–4.4 V. With the addition of 0.5 wt% MMDS in the electrolyte, the capacity retention of the cells increases from 70.7% to 94.1% after 100 cycles in 3.0–4.4 V, but has no difference in 3.0–4.2 V. The enhanced cycling performance of the cells with MMDS additive is ascribed to the surface modification of LiNi0.5Co0.2Mn0.3O2 cathode, which not only improves the conductivity of cathode electrolyte interface film but also suppresses the solvent decomposition at high voltage.
TL;DR: In this article, a proton exchange membrane fuel cell (PEMFC) is proposed to operate in an alkaline media with the potential advantage of facile kinetics of oxygen reduction reaction on non-precious group metals and stability at high pH values.
Abstract: Development of proton exchange membrane fuel cells, have to be tempered with the cost, a significant portion of which is due to the so called ‘stability criterion’ restricting the choice to Pt and Pt alloy materials.Fuelcellsoperating inalkaline media havepotential advantage of facile kinetics of oxygen reduction reaction on non-precious group metals and stability at high pH values. In addition, the hydrodynamics of alkaline membrane fuel cells is potentially beneficial considering the problems associated with water management in a conventional PEM fuel cell. Further, highly stable PTFE based membranes are not required under alkaline conditions as the membranes are less prone to attack by peroxide ions. Even though AEMFCs alleviate most of the hurdles associated with PEM fuel cells, state of art performance of H2/air does not exceed half of the performance shown by H2 fed PEM fuel cells using Pt based catalysts (compare 700 mW cm −2 for PEMFCs 1 at 0.65 V
TL;DR: In this article, small mesophase graphite (SMG) is combined with either styrene-butadiene rubber/carboxymethyl cellulose (SBR/CMC) or polyvinylidene difluoride (PVDF) binder to constitute the anodes for high-power Li-ion batteries.
Abstract: Small (micron)-sized mesophase graphite (SMG) is combined with either styrene-butadiene rubber/carboxymethyl cellulose (SBR/CMC) or polyvinylidene difluoride (PVDF) binder to constitute the anodes for high-power Li-ion batteries. The binder effects on the electrochemical performance of the SMG/LiFePO4 18650-battery are evaluated. Using SBR/CMC binder reduces the first-cycle irreversible capacity loss and most surprisingly enhances the high-temperature (55°C) cycle-life of the battery. Surface analyzes suggest that the enhancements are consistent with reduced formation of the solid-electrolyte-interphase (SEI) layer on graphite anode, indicating that composition of binder can have significant influence on SEI formation on anode.
TL;DR: In this paper, the Magneli phase titanium sub-oxides conductive ceramic particles were added to Zn electrodes for use in Ni/Zn batteries for better cycling stability, higher discharge capacity, and corrosion resistance.
Abstract: The Magneli phase titanium sub-oxides conductive ceramic particles were added to Zn electrodes for use in Ni/Zn batteries. X-ray diffraction analysis indicated that the basis of the conductive ceramic was Ti4O7 and transmission electron microscopy showed that the particles were uniform in shape and size. The electrochemical performance of a Zn electrode with the conductive ceramic as the conductive additive was investigated by charge/discharge cycling test, cyclic voltammetry, and Tafel plot. Compared with a Zn electrode with acetylene black and without conductive additive, the electrode with conductive ceramic showed better cycling stability, higher discharge capacity, and corrosion resistance.
TL;DR: In this article, the effect of curing temperature of a common current collector, silver, on the polarization area specific resistance (ASR) of a cathode was investigated, and the results explicitly showed that at least one order of magnitude lower ASR for a current collector with Ag cured at 800-C than that cured at 650-C of the same cathode configuration.
Abstract: The true functionality of a current collector employed in electrochemical cells is to ensure a lowresistance steady electrons flow between the cell and instrumentation without involving in any local electrochemical reactions of the electrode. In this study, we investigated the effect of curing temperature of a common current collector, silver, on the polarization area specific resistance (ASR) of a cathode. The results explicitly showed that at least one order of magnitude lower ASR for a cathode with Ag cured at 800◦C than that cured at 650◦C of the same cathode configuration. Microscopic analysis of the 800◦C-cured cells revealed a deep penetration and abundant distribution of Ag into the cathode/electrolyte interfacial region. These finely dispersed and highly conductive Ag particles/agglomerates are ORR (oxygen reduction reaction)-active, thus engaging in the local electrochemical reaction and overshadowing the true properties of the cathode under investigation. Based on these results, we call for caution when using Ag as a current collector for electrochemical measurements, particularly at a temperature ≥650◦C. © 2012 The Electrochemical Society. [DOI: 10.1149/2.010301eel] All rights reserved.
TL;DR: In this paper, a cathode with an initial discharge capacity of 163 mAh/g (98% of theoretical value) at C/20 rate with impressive capacity retentions until 50 cycles attributed to the combined contributions of surface coating and porous structure that serve as facile electrical conduits for ion/electron transport.
Abstract: /C cathode delivered an initial discharge capacity of 163 mAh/g (98% of theoretical value) at C/20 rate withimpressive capacity retentions until 50 cycles attributed to the combined contributions of surface coating and porous structure thatserve as facile electrical conduits for ion/electron transport.© 2012 The Electrochemical Society. [DOI: 10.1149/2.003204eel] All rights reserved.Manuscript submitted May 30, 2012; revised manuscript received July 2, 2012. Published August 24, 2012.
TL;DR: In this article, the incorporation of h-BN nanosheets into the nickel matrix significantly improves corrosion resistance in 3.5 wt% NaCl solution, and the results demonstrated that the incorporation improved corrosion resistance.
Abstract: Nickel matrix composite coatings were successfully fabricated by the incorporation of h-BN (hexagonal boron nitride) nanosheets using the pulse electrodeposition technique. Electrodeposition was carried out by dispersing 5–20 g/L of h-BN nanosheets into the sulfamate electrolytic bath. Composite coatings have shown smooth surface over pure nickel coating. XRD patterns of the composites have shown mixed orientations of crystallites unlike pure nickel which showed preferred (100) orientation. The results demonstrated that the incorporation of h-BN nanosheets into the nickel matrix significantly improves corrosion resistance in 3.5 wt% NaCl solution. © 2012 The Electrochemical Society. [DOI: 10.1149/2.003303eel] All rights reserved.
TL;DR: LiCo0.5Mn 0.5PO4 is readily prepared via a modified hydrothermal route to investigate the effect of Mn substitution on LiCoPO4 as discussed by the authors.
Abstract: LiCo0.5Mn0.5PO4 is readily prepared via a modified hydrothermal route to investigate the effect of Mn substitution on LiCoPO4. The results show that the Mn substitution plays a profound role in reducing the particle size and stabilizing the surface of the olivine materials, thus leading to highly improved electrochemical properties versus the pure LiCoPO4 .T he LiCo0.5Mn0.5PO4 can deliver a reversible capacity of 126 mAh g−1 and maintain 88% of that over 30 cycles, thereby manifesting its potential for energy storage