Liquid-state Electrode Research Articles

Inherent Water Competition Effect-Enabled Colloidal Electrode for Ultra-stable Aqueous Zn-I Batteries.

Electrode material stability is crucial for the development of next-generation ultralong-lifetime batteries. However, current solid- and liquid-state electrode materials face challenges such as rigid atomic structure collapse and uncontrolled species migration, respectively, which contradict the theoretical requirements for ultralong operation lifetimes. Herein, we present a design concept for a soft colloid polyvinylpyrrolidone iodine (PVP-I) electrode, leveraging the inherent water molecule competition effect between (SO4)2- from the electrolyte and PVP-I from the cathode in an aqueous Zn||PVP-I battery. Electrochemical demonstrations measured under various simulated and practical (integrated with photovoltaic solar panel) conditions highlight the potential for an ultralong battery lifetime. The PVP-I colloid exhibits a dynamic response to the electric field during battery operation. More importantly, the water competition effect between (SO4)2- from the electrolyte and water-soluble polymer cathode materials establishes a new electrolyte/cathode interfacial design platform for advancing ultralong-lifetime aqueous batteries.

Nitrate ion-selective electrode based on Cu(I) neocuproine complex

The ion association complex of is(neocuproine)-copper(I) and nitrate has been employed as new electroactive material for a nitrate ionselective electrode. Two different types of the electrode constructions have been examined, liquid-state electrode and PVC plastic membrane electrode with direct solid contact. Data on sensitivity and selectivity of these systems are reported. The PVC membrane electrode has been employed for the potentiometric nitrate determination in tap water (>0.2ppm of NO3−-N).

Construction of a new Hg 2+-selective liquid-state electrode

The construction and basic characteristics of a new liquid-state Hg 2+-selective membrane electrode are discussed. The membrane consists of the PAN chelate of Hg(II), dissolved in CHCl 3. The linear response range of the electrode is 10 −1 −10 −5 M Hg 2+ with a slope of 28.5 mV/decade of concentration. The response time of the electrode in dilute solutions is less than 3 min, and in concentrated solutions it is only a few sec. The electrode has been used in precipitation or complexation titrations in which Hg 2+ is involved ( e.g., in the determination of some organic compounds in drug synthesis).

Determination of nitrate in water with a new construction of ion-selective electrode

A new design of the liquid-state electrode for nitrate ions is proposed. It contains a porous wick soaked with the liquid ion-exchanger, and has no internal reference solution. This electrode was used for nitrate determination of tap water at the level 8–10 p.p.m. The effects of chloride and hydrogencarbonate are eliminated by the addition of silver sulphate and a phosphate buffer, which also maintains constant ionic strength. Precision of a series of measurements is better than 2%, but the results show differences up to 10% compared to the colorimetric brucine procedure.

Ion Selective Electrodes Based on Brilliant Green Tetrathiocyanatezincate(II)

Abstract Liquid state, heterogeneous silicone rubber and carbon paste electrodes based on Brilliant green tetrathiocyanatozincate(II) have been prepared and studied. The liquid state electrode, consisting of a 10−3 M solution of Brilliant green tetrathiocyanatozincate(II) in o-dichlorobenzene supported on lightly cross-linked natural rubber, was the most satisfactory. This electrode responded rapidly when placed in 10−4 to 10−1 M solutions of zinc containing a twenty-fold excess of thiocyanate. The potential concentration slope (-29.5 mV per decade change in concentration) was that 2-expected for response to Zn(SON)4 2-. The silicone-rubber and carbon paste electrodes also gave near-Nernstian response, but responded more slowly.

Selectrode TM—the universal ion-selective solid-state electrode : Part I. Halides

The ion-sensitive surface of the new solid-state electrode proposed consists of a very thin layer of an electroactive material adsorbed on the surface of hydrophobized graphite. The electrode has neither an inner reference aqueous solution nor a membrane, its construction being similar to that of the previously described liquidstate electrode. The unique advantage of this new solid-state electrode is that its ionsensitive surface can be easily renewed or replaced by another material so that the electrode can be made selective towards different ions in the sample solution. Experiments with Selectrodes TM activated with silver halides have confirmed that they exhibit a pure Nernstian respon'se towards iodide, bromide and chloride, have excellent potential stabilities even during long-term continuous operation and show sensitivities in agreement with the solubilities of AgI, AgBr and AgCl, respectively. Use of various other electroactive materials will be described later. These Selectrodesö can be treated formally as second-order electrodes. This makes it possible to predict Selectrodes TM potentials and to understand the observed phenomena of sub- and supersensitivity. Comparison between solid-state membrane electrodes and Selectrodes TM is attempted.

The liquid-state, iodide-selective electrode

The ion-sensitive surface of the liquid-state electrode is formed by a very thin layer of an organic liquid, adsorbed at the surface of porous graphite. The composition of this organic phase, which must be immiscible with water, can be chosen so that the electrode responds only to the activity of a certain ion in the measured aqueous sample. The performance and construction of a liquid-state electrode with solutions of iodine in carbon tetrachloride, benzene and mesitylene as the organic phase is described. The electrode is suitable for measurement of iodide activities down to 10 −6 M; it has selectivity ratios for iodide over bromide of about 10 −3 and over chloride ion of better than 10 −4. In contrast to the solid-state iodide-selective electrode (AgI/Ag 2S membrane), the liquid-state electrode is not sensitive to light at any level of the iodide activities studied, but it is sensitive to species which would reduce iodine to iodide.

The liquid-state electrode (A preliminary communication)

The liquid-state electrode (A preliminary communication)