Inhibition of sintering in molten carbonate fuel cell anodes

Molten carbonate fuel cells operate at 600–700°C. At these high temperatures, high surface area nickel anodes lose their activity rapidly due to sintering. A study of the sintering kinetics of Ni, Ni-Ag and Ag powder revealed that when Ni and Ag particles are present in similar numbers, sintering is significantly inhibited. This is achieved by minimizing volume diffusion between adjacent particles — Ni and Ag have virtually no solid solubility at any temperature. Paste electrolyte cells using such electrodes gave 114 mA/cm² at 0.65 V on 80% H₂/20% CO₂ fuel, compared to 80 mA/cm² at 0.65 V for a cell using sintered nickel anodes.     

Measuring mercury ion concentration with a carbon nano tube paste electrode using the cyclic voltammetry method

A simply prepared carbon nano tube paste electrode (CNTPE) was utilized for monitoring mercury ion concentration using the cyclic voltammetry (CV) method and the square wave anodic stripping voltammetric (SWASV) method. The CNTPE was compared with various conventional electrodes. The CNTPE method was applied to determine the concentration of trace levels of Hg(II) in several water samples, which yielded a relative error of 0.6% with a concentration of 0.20 mg L^–1 Hg(II). It was deposited at –0.5 V (vs Ag/AgCl), which was subsequently reduced to +0.20 V to strip it on the CNTPE. The optimal experimental conditions for the analysis were found to be as follows: pH value of 4 for the medium; deposition potential of –0.5 V; deposition time of 210 s; SW frequency of 40 Hz; SW amplitude of 100 mV, and step potential of 25 mV. Given these optimum conditions, a linear range was observed within the concentrations of 1.0–25.0 g L^–1 and 40.0–200.0 g L^–1. The detection limit was found to be 0.42 g L^–1.     

Investigation of the 1-methyl-3-ethylimidazolium chloride-AlCl3/LiAlCl4 system for lithium battery application Part I: Physical properties and preliminary chronopotentiometric study

The applicability of the 1-methyl-3-ethylimidazolium chloride — AlCl₃ system for lithium battery application was investigated. Lithium chloride was found to dissolve up to 1.59 mole ratio of LiAlCl₄/MeEtImAlCl₄ upon reaction between LiCl and AlCl₃ in the melt. Density, conductivity and viscosity of the melt upon addition of LiAlCl₄ were determined. The density was found to increase monotonically from 1280 to 1480 kg m^–3, while the conductivity decreased rapidly from the initial value of 5.6 mS to a steady plateau at 3.4 mS. The viscosity was varied from 1.46 Ns m^–2 to a small but distinct initial fall prior to rising to 2.75 Ns m^–2 when the mole ratio of LiAlCl₄ increased from zero to 1.59. The chronopotentiometric studies indicate a satisfactory electrochemical behaviour with no apparent attack of the melt by the formation of the reactive lithium alloys. 350 cycles were achieved with cycling efficiency over 90% using an optimal c.d. of 6 mA cm^–2 for lithium deposition on aluminium substrate in the melt. Prolonged cycling improved the nucleation rate but led to an increase in the internal resistance and a gradual reduction in the charge and discharge capacity.     

New electrodes for oxygen evolution in acidic solution

Conventional electrowinning of metals such as zine and copper from 1–1.5 kmol m^–3 H₂SO₄ electrolytes involves anodic oxygen evolution at Pb alloy/PbO₂ anodes operating at 200–800 A m^–2. The oxygen overpotential, estimated to be about 0.6 V, constitutes a significant proportion of the cell voltage (typically 2.5 V for Cu and 3.3 V for Zn). The objective of this work was to lower the anode overpotential and so decrease the process specific energy requirements, by devising new anode materials based on: (1) PTFE-bonded PbO₂ catalysts, supported on Pb–Ag alloys; (2) modification of the pore structure of porous electrodes to maximize the utilization of the available surface without the use of PTFE bonding. Both methods are shown to produce significant benefits in lowering oxygen overpotentials, though the latter technique has been tested only in alkaline electrolytes, as yet. However, with the former approach, substrate oxidation through the porous catalyst layer has been found to cause catalyst shedding after>60 h at 1 kA m^–2, though careful pre-oxidation of the anode substrate appears to extend the anode life.Paper presented at the 2nd International Symposium on Electrolytic Bubbles organized jointly by the Electrochemical Technology Group of the Society of Chemical Industry and the Electrochemistry Group of the Royal Society of Chemistry and held at Imperial College, London, 31st May and 1st June 1988.     

Electrochemical reduction of carbon dioxide to ethylene with high Faradaic efficiency at a Cu electrode in CsOH/methanol

The electrochemical reduction of CO₂ with a Cu electrode in CsOH/methanol-based electrolyte was investigated. The main products from CO₂ were methane, ethylene, ethane, carbon monoxide and formic acid. A maximum Faradaic efficiency of ethylene was 32.3% at −3.5 V vs. Ag/AgCl saturated KCl. The best methane formation efficiency was 8.3% at −4.0 V. The ethylene/methane current efficiency ratio was in the range 2.9–7.9. In the CsOH/methanol, the efficiency of hydrogen formation, being a competitive reaction against CO₂ reduction, was depressed to below 23%.     

HBr electrolysis in the Ispara Mark 13A flue gas desulphurization process: electrolysis in a DEM cell

The potential application of a DEM cell for the electrolysis of hydrogen bromide in the Ispra Mark 13A process for flue gas desulphurization has been tested in a number of laboratory experiments and in long-duration tests in a bench-scale plant of the process. Satisfactory electrode materials have been found, i.e. Hastelloy C 276 for the cathode and a RuO₂ coating on titanium for the anode. Both electrode materials showed a good stability during a 1500 hours experiment. Cell voltage/current density relationships have been determined during bench-scale plant operation. A typical value is 1.5V at a current density of 2.5 kA m^–2. It has been shown that in an undivided cell a cathodic back reaction occurs which causes a decrease of the current efficiency. Under normal operation conditions current efficiencies of about 90% are obtained.A simplified flow model for the DEM cell was developed which is useful in understanding the phenomena which occur during scale-up of the cell. An industrial size installation for the production of 170 kg h^–1 of bromine at a current density of 2 kA m^–2 was constructed and has been in operation since August 1989.Nomenclature a _x thermodynamic activity of the constituentx (mol cm^–3) - C bromine concentration (mol l^–1) - e _z local current efficiency - e _ov overall cell efficiency - E _a ⁰ anodic standard potential (V) - E _c ⁰ cathodic standard potential (V) - E _a ^c equilibrium anode potential (V) - E _e ^c equilibrium cathode potential (V) - F Faraday number (C mol^–1) - g _a anodic overpotential (V) - g _c cathodic overpotential (V) - G electrolyte flow rate (l h^–1) - i current density (A m^–2) - K _c cathodic back reaction rate factor (l mol^–1) - L cell width (m) - n number of electrons involved (n=2) - R gas constant (J K^–1 mol^–1) - R _cell cell resistance (ohm m²) - R _c circuit resistance (ohm m²) - w _b local cathodic back reaction rate (mol m^–2 h^–1) - w _th local theoretical reaction rate (mol m^–2 h^–1) - W _th overall theoretical reaction rate (mol h^–1) - T temperature (K) - Z cell length (m)     

Electrochemical reduction of solutions of ReF6 in fused LiF–NaF–KF eutectic mixture

Electrolyte was prepared by introducing gaseous ReF₆ into the molten LiF–NaF–KF eutectic at 600 °C. The electrochemical properties of the solutions were studied by voltammetric techniques. The reduction of ReF₈ ^2– to Re occurred via a single irreversible step with diffusion controlled mass transfer. The diffusion coefficient of ReF₈ ^2– was 8 × 10^–10 m² s^–1 and the cathodic transfer coefficient was 0.13. Well-crystallized pure rhenium layers, up to 50 m thick, were obtained on W, Ag, graphite and vitreous carbon substrates and were examined by SEM and X-ray diffraction techniques.     

Electrochemical reduction of silver thiosulphate complexes Part II Mechanism and kinetics

In this paper the thermodynamic data for complex formation between Ag⁺ and S₂O_{3 2–} ions, determined previously, are applied to kinetic investigation of the reduction of silver thiosulphate complexes. Both electrochemical (linear sweep voltammetry on a rotating disc electrode) and surface analytical (Auger electron spectroscopy) techniques are used. The deposits resulting from the electrodeposition of silver thiosulphate complexes are shown to be composed of silver and to be polycrystalline. The reduction follows a mechanism involving mass and charge transfer and chemical reaction steps. The relevant kinetic parameters are calculated and a rate equation describing the kinetics of the reduction is given.List of symbols a activity (M) - c concentration (M) - j current density (A m^–2) - j _c current density of charge transfer (A m^–2) - j _m current density of mass transfer (A m^–2) - k rate constant (m s^–1) - y activity coefficient (molarity scale) - D diffusion coefficient against gradient of concentration (m² s^–1) - D diffusion coefficient against gradient of electrochemical potential (m² s^–1) - E electrode potential vs NHE (V) - I ionic strength (M) - T temperature (K) Greek symbols a transfer coefficient - _1n stability constant of Ag(S₂O₃) _n (^2n–1)- - kinematic viscosity (m² s^–1) - rotation speed of the electrode (rad s^–1) Indices b bulk of the solution - f free (= uncomplexed) - 1,n related to complex Ag(S₂O₃)_n ^(n–1) - t total Constants F Faraday constant (96486 A s mol^–1) - R universal gas constant (8.3145 Jmol^–1 K^–1)     

The behaviour of a trickle tower electrolytic cell for the production of cobalt(III) acetate from cobalt(II) acetate

The production of Co(III) acetate from Co(II) acetate using a bipolar trickle tower of graphite Raschig rings was investigated. Space time yields up to 18 kg m^–3 h^–1 were obtained, which showed no improvement over those achievable in a conventional plate and frame cell. A mathematical model of the system indicated that the electrode reactions occurred almost entirely at the opposing annular surfaces between consecutive layers of Raschig rings and that the unexpectedly low performance of the device was most probably due to the unfavourable mass transport conditions which existed in the intervening gaps.Nomenclature a annular cross sectional area of one Raschig ring (m²) - b _C kinetic exponential constant for reduction of Co(III) (V^–1) - b _A kinetic exponential constant for oxidation of Co(II) (V^–1) - b _H kinetic exponential constant for hydrogen evolution (V^–1) - b ₀ kinetic exponential constant for oxygen evolution (V^–1) - [Co(II)] concentration of Co(II) (mol m^–3) - [Co(III)] concentration of Co(III) (mol m^–3) - F Faraday constant (96 487 C mol^–1) - f fraction of total flow by-passing the annular gap between adjacent Raschig rings in a vertical row - I current per vertical column of rings (A) - k _C rate constant for reduction of Co(III) (A m mol^–1) - k _A rate constant for oxidation of Co(II) (A m mol^–1) - k _H rate constant for hydrogen evolution (A m^–2) - k _O rate constant for oxygen evolution (A m^–2) - k _L mass transfer coefficient (m s^–1) - Q flow rate per vertical row of Raschig rings (m³s^–1) - v volume of annular gap between adjacent Raschig rings in a vertical row (m³) - V superficial velocity of electrolyte (m s^–1) - _A anodic potential (V) - _C cathodic potential (V)     

Exploration of molten hydroxide electrochemistry for thermal battery applications

The electrochemistry of molten LiOH–NaOH, LiOH–KOH, and NaOH–KOH was investigated using platinum, palladium, nickel, silver, aluminum and other electrodes. The fast kinetics of the Ag⁺/Ag electrode reaction suggests its use as a reference electrode in molten hydroxides. The key equilibrium reaction in each of these melts is 2 OH^– = H₂O + O^2– where H₂O is the Lux-Flood acid (oxide ion acceptor) and O^2– is the Lux–Flood base. This reaction dictates the minimum H₂O content attainable in the melt. Extensive heating at 500 °C simply converts more of the alkali metal hydroxide into the corresponding oxide, that is, Li₂O, Na₂O or K₂O. Thermodynamic calculations suggest that Li₂O acts as a Lux–Flood acid in molten NaOH–KOH via the dissolution reaction Li₂O_(s) + 2 OH^– = 2 LiO^– + H₂O whereas Na₂O acts as a Lux–Flood base, Na₂O_(s) = 2 Na⁺ + O^2–. The dominant limiting anodic reaction on platinum in all three melts is the oxidation of OH^– to yield oxygen, that is 2 OH^– 1/2 O₂ + H₂O + 2 e^–. The limiting cathodic reaction in these melts is the reduction of water in acidic melts ([H₂O] [O^2–]) and the reduction of Na⁺ or K⁺ in basic melts. The direct reduction of OH^– to hydrogen and O^2– is thermodynamically impossible in molten hydroxides. The electrostability window for thermal battery applications in molten hydroxides at 250–300 °C is 1.5 V in acidic melts and 2.5 V in basic melts. The use of aluminum substrates could possibly extend this window to 3 V or higher. Preliminary tests of the Li–Fe (LAN) anode in molten LiOH–KOH and NaOH–KOH show that this anode is not stable in these melts at acidic conditions. The presence of superoxide ions in these acidic melts likely contributes to this instability of lithium anodes. Thermal battery development using molten hydroxides will likely require less active anode materials such as Li–Al alloys or the use of more basic melts. It is well established that sodium metal is both soluble and stable in basic NaOH–KOH melts and has been used as a reference electrode for this system.     

Zinc-air cell with neutral electrolyte

The zinc-air electrochemical system in 5m NH₄Cl was studied. The optimum electrolyte-zinc ratio was found to be 50 ml g^–1 Zn and the optimum electrolyte-cathode ratio, 15 ml cm^–2 of carbon cathode. The air cathode polarization is not increased by intermittent usage of the cell. Electrodes made from zinc sponge with addition of lead show the smallest corrosion in the given electrolyte. The cell voltage is about 0.9–0.95 V at a load of 10 mA cm^–2 of carbon cathode at ambient temperature.     

Electrosynthesis of hydrogen peroxide in acidic solutions by mediated oxygen reduction in a three-phase (aqueous/organic/gaseous) system Part II: Experiments in flow-by fixed-bed electrochemical cells with three-phase flow

The second part of the work concerned with mediated electrosynthesis of H₂O₂ in acidic solutions (pH 3) deals with investigations using divided flow-by fixed bed electrochemical cells operated with co-current three-phase flow (aqueous/organic emulsion and O₂ gas at 0.1 MPa). Graphite felt (GF) and reticulated vitreous carbon (RVC) were evaluated as cathodes at superficial current densities up to 3000 A m^–2. Typically, at current densities above 600 A m^–2 graphite felt yielded higher peroxide concentrations per pass and current efficiencies, most likely due to the almost an order of magnitude higher organic liquid to solid mass transfer capacity for 2-ethyl-9,10-anthraquinone (EtAQ) mediator, that is, 0.13 s^–1 in the case of GF vs 0.015 s^–1 for RVC with 39 ppc (pores per cm). Factorial experiments revealed a positive interaction effect between superficial current density and emulsion load with respect to the current efficiency for H₂O₂ electrosynthesis. Thus, at the highest investigated superficial current density of 3000 A m^–2, the current efficiency was 84% when the emulsion load was at the highest explored level of 11.7 kg m^–2 s^–1, whilest for the lowest level of emulsion load, 2.8 kg m^–2 s^–1, the current efficiency for H₂O₂ was 18%. Furthermore, the presence of 1 mM cationic surfactant, tricaprylmethylammonium chloride (CH₃(C₈H₁₇)₃N⁺Cl^–, A336), had a positive main effect of about 12% on H₂O₂ current efficiency and there was also a positive synergistic effect between surfactant and emulsion load, estimated at about 7%. The aqueous to organic phase volume ratio, in the range of 0.9/1 and 3/1, had a statistically insignificant effect on the current efficiency for H₂O₂ generation. A decrease of the aqueous to organic phase volume ratio from 3 to 0.9 increased the cell voltage from about 6.5 to 7.3 V.     

Effect of silver catalyst on the activity and mechanism of a gas diffusion type oxygen cathode for chlor-alkali electrolysis

Application of a gas-diffusion type oxygen cathode will contribute to energy saving in chlor-alkali electrolysis. For this purpose the development of gas-diffusion electrodes with high performance and durability is essential. We have investigated the performance for oxygen reduction and the mechanism of its on gas-diffusion electrodes with and without Ag catalyst in order to develop such oxygen cathodes with high performance and durability. It has been found that an electrode with no catalyst, that is, carbon support only in the reaction layer, shows electrochemical activity for oxygen reduction in 32 wt % NaOH at 80 °C and 1 atm O₂, but loading of 2 mg cm^–2 Ag of particle size 300 nm, not only improves the activity by about 100 mV but promotes the four-electron reduction to produce OH^–, while H₂O₂ is the predominant reaction intermediate in the absence of the Ag catalyst. The production of H₂O₂ has been demonstrated by conducting CV measurements to detect H₂O₂ in the anodic scan after a cathodic sweep up to 0.3 V vs RHE. It has been shown that the gas-diffusion type oxygen cathode with Ag catalyst has the high performance and durability necessary for chlor-alkali electrolysis.     

A study of transport of hydroxyl ion in a chlor-alkali diaphragm

The loss of hydroxyl ions by diffusion and back migration to the anolyte compartment is the major source of efficiency loss in a chlor-alkali diaphragm cell. The transfer rate of hydroxyl ions across the diaphragm depends on diaphragm properties and electrolyte flow rate inside the diaphragm. This work examines the concentration distribution of hydroxyl ions across the diaphragm in a laboratory cell. A numerical computation is carried out to optimize the diaphragm structure and current density based on the minimum production cost of chlorine. The optimum current density is found to be 50% lower than the present operating current density in the chlor-alkali industry.Nomenclature A _p apparent cross-sectional area of the diaphragm (m²) - A _T true cross-sectional area of the pores (m²) - C _OH concentration of the hydroxyl ion at any pointx along thex-direction (kg mol m^–3) - C _K catholyte concentration (kg mol m^–3) - C dimensionless concentration given in Equation 11 - C _D unit diaphragm cost ($ kg^–1) - C _E unit direct electrical energy cost ($ kg^–1) - C ₁ unit specific investment cost ($ kg^–1) - D diffusion coefficient of the hydroxyl ion (m² s^–1) - E ₀ open circuit voltage (V) - E total cell voltage (V) - F Faraday's constants (96 487 C g equiv^–1) - i _P apparent current density based on apparent area of the diaphragm,A _P (A m^–2) - i _T true current density based on true crosssectional area of the pores,A _T (A m^–2) - I magnitude of total current through the cell (A) - (IR)_BUS voltage drop in the bus-bar (V) - (IR)_SOLN voltage drop in the solution (V) - (IR)_DIA voltage drop in the diaphragm (V) - N _OH flux of hydroxyl ion (kg mol m^–2 s^–1) - K _S average conductivity of the solution (ohm^–1 m^–1) - k ₁ energy cost ($ kWh^–1) - K ₂ capital cost of the electrolyte cell ($ m^–2) - K ₃ cost coefficient of diaphragm ($ m^–2) - K ₅ unit cost of the raw material ($ kg^–1) - l effective pore length (m) - l ₁ distance between the anode and the cathode (m) - L life period of the diaphragm (yr) - molecular weight of chlorine gas (kg) - M _NaCl molecular weight of sodium chloride (kg) - n number of years of amortization which in principle is given by the life time of the cell (yr) - N _C total number of cells (dimensionless) - p production rate of chlorine gas (kg yr^–1) - R resistance (ohm) - r ₀ resistance of the solution (ohm) - S annual interest rate (%) - U _OH– mobility of hydroxyl ion (kg mol m²V^–1 C^–1 s^–1) - electrolyte velocity along the x-direction inside diaphragm (m s^–1) - _S superficial velocity (m s^–1) - V _W volume of water lost from the catholyte compartment due to evaporation and cathodic reaction (m³ s^–1) - x axial coordinate - Z valence of hydroxyl ion (kg equiv kg^–1 mol^–1) - diaphragm thickness (m) - porosity (%) - current efficiency (dimensionless) - _a anodic overpotential (V) - _c cathodic overpotential (V) - tortuosity factor (dimensionless)     

The role of supporting electrolyte during the electrocatalytic hydrogenation of aromatic compounds

The electrocatalytic hydrogenation of benzene, aniline, and nitrobenzene was investigated at a Raney nickel powder cathode. The single phase electrolyte consisted of t-butanol, water, and a hydrotropic salt, either sodium or tetraethylammoniump-toluenesulphonate (TEATS). The hydrogenation of benzene was achieved only in the latter case; the only product detected was cyclohexane. The highest current efficiency (73%) was obtained at 50° C, 1.0m benzene, 2.5m TEATS, and at an apparent current density of 4.0 mA cm^–2. Aniline was electrocatalytically hydrogenated to cyclohexylamine only in the presence of a quaternary ammonium ion supporting electrolyte (containing either Br^– orp-toluenesulphonate anions), with product current efficiencies of 40%. When nitrobenzene was hydrogenated with a sodiump-toluenesulphonate supporting electrolyte, only nitro group reduction was observed. When the supporting electrolyte was TEATS, both nitro group reduction and aromatic ring hydrogenation occurred.     

Modification of Porous Silica with Activated Carbon and its Application for Fixation of Yeasts

Mixtures of small silica particles and activated carbon were heated at 1250–1450°C in an inert atmosphere to make nano- and macro-sized porous silica for incorporating yeast in the porous strucrure. Without activated carbon, porous silica of 45–60% porosity and 15–30 m pore diameter was produced with a specific surface area below 1 m²/g. By the addition of 8 wt% of activated carbon granules, the surface area of porous silica increased to 100 m²/g at 1250°C. It was confirmed that there were micropores(1.2 nm) and mesopores(4.0 nm) due to activated carbon granules in porous silica when granule type activated carbon was used. However, in the case of activated carbon fiber, its micro- and mesoporous structure was destroyed in the firing process. The fixation of Z. rouxii yeasts was promoted on the porous silica with activated carbon.     

Electrochemical reduction of nitrogen oxyanions in 1 M sodium hydroxide solutions at silver,copper and CuInSe2 electrodes

The reduction of nitrate and nitrite ions was studied in 1m NaOH supporting electrolyte. Voltammetric investigations show that, on silver cathodes, nitrate reduction begins at potentials about 500 mV more positive than nitrite reduction, the latter being superimposed on hydrogen evolution. Electrolyses of nitrate solutions at –1.4V/sce give nitrite with good selectivity. On copper cathodes, nitrate and nitrite reductions occur in the same region of potentials and show similar voltammetric profiles. The dominant product of nitrite reduction is ammonia, whereas nitrate may be reduced to nitrite at –1.1 V/sce and to ammonia with high yields at –1.4 V/sce. Reduction of nitrogen oxyanions may also be performed on CuInSe₂ (photo)cathodes. Photoassisted reductions of nitrate performed on p-CuInSe₂ at –1.4 V/sce gave mixtures of ammonia, nitrite and hydrogen.     

Electrochemical studies on gold electrodes in acidic solutions of thiourea containing gold (I) thiourea complex ions

Electrochemical studies were made of the behaviour of gold electrodes in degassed acidic solutions containing between 0.00l to 0.03 M thiourea and between 10^–5 to 10^–3 M gold(I)thiourea. At anodic overpotentials of up to 0.3 V the dissolution of gold was rapid, and nearly reached the maximum diffusioncontrolled rate. The exchange current density was greater than 10^–6 A cm^–2, and dissolution proceeded at 100% efficiency. At higher anodic potentials, thiourea was oxidized to formamidine disulphide and other sulphur-containing compounds and the dissolution of gold became partly inhibited, while the current efficiency decreased markedly.The reduction of gold(I)thiourea was diffusion-controlled at cathodic overpotentials between –0.15 to –0.35 V, after which slight inhibition was observed. Thiourea itself did not contribute to the cathodic reaction, but formamidine disulphide could be reduced on a freshly deposited gold surface; in the absence of gold(I)thiourea in the solution, the reduction of formamidine disulphide caused rapid passivation of the gold surface. In 0.01 M thiourea and 0.1 M sulphuric or perchloric acid, the diffusion coefficient of the Au(CS(NH₂)₂) ₂ ⁺ ion was 1·1 x 10^–5 cm² s^–1 at 30°C.The standard reduction potential at 30° C of the redox couple Au(CS(NH₂)₂) ₂ ⁺ ¦Au on a fresh gold surface wasE ₀=0.352 V, but on a passivated gold surface this value increased to as much asE ₀=041V.     

Electrospun poly(lithium 2‐acrylamido‐2‐methylpropanesulfonic acid) fiber‐based polymer electrolytes for lithium‐ion batteries

Novel single‐ion conducting polymer electrolytes based on electrospun poly(lithium 2‐acrylamido‐2‐methylpropanesulfonic acid) (PAMPSLi) membranes were prepared for lithium‐ion batteries. The preparation started with the synthesis of polymeric lithium salt PAMPSLi by free‐radical polymerization of 2‐acrylamido‐2‐methylpropanesulfonic acid, followed by ion‐exchange of H⁺ with Li⁺. Then, the electrospun PAMPSLi membranes were prepared by electrospinning technology, and the resultant PAMPSLi fiber‐based polymer electrolytes were fabricated by immersing the electrospun membranes into a plasticizer composed of ethylene carbonate and dimethyl carbonate. PAMPSLi exhibited high thermal stability and its decomposition did not occur until 304°C. The specific surface area of the electrospun PAMPSLi membranes was raised from 9.9 m²/g to 19.5 m²/g by varying the solvent composition of polymer solutions. The ionic conductivity of the resultant PAMPSLi fiber‐based polymer electrolytes at 20°C increased from 0.815 × 10^?5 S/cm to 2.12 × 10^?5 S/cm with the increase of the specific surface area. The polymer electrolytes exhibited good dimensional stability and electrochemical stability up to 4.4 V vs. Li⁺/Li. These results show that the PAMPSLi fiber‐based polymer electrolytes are promising materials for lithium‐ion batteries. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Electrochemical and physical chemical properties of sp carbon microrods

We investigated sp² carbon microrods resulting from the reaction of lithium with hexachlorobenzene. The material exhibits high surface area (200-340 m²/g, depending on heat treatment) and a reversible lithium storage capacity in excess of 500 mA h/g. The discharge/charge behavior of the material resembles that of high specific capacity non-graphitic carbon. Without distinguishable plateaus, the reversible intercalation of lithium occurs at a broad potential window below 1 V vs. Li/Li⁺. A possible mechanism for the rod formation, based on SEM results, is briefly considered.