Sulfate-based electrolyte

That is, in contact with a sulfate-based electrolyte, at the cathode ... 

A copper-plating electrolyte, specifically optimized for copper metallization of interconnects on silicon wafers is described. The copper sulfate based electrolyte features no (or tow) sulfuric acid and a high (>0.8 M) copper concentration. Elimination (or reduction) of the acid increases the electrolyte resistivity, thereby minimizing the... 

Deposition and corrosion of Cu thin layers from an aqueous sulfate-based electrolyte were studied in situ with an AFM-EQCM system by Bund et al. [66]. The shift of the resonance frequency and of the damping of the quartz crystal (EQCM), on one side, and the evolution of surface roughness (AFM), on the other side, could be thus monitored simultaneously. No disturbance of the AFM response by the oscUlating quartz or vice versa was observed in this study. The authors proved that a quantitative separation of internal (information given by EQCM) and external friction (which is the roughness contribution, obtained by AFM) of the solid materials is possible by combining AFM and EQCM techniques. 

Figure 2.3 shows two galvartic cells indicating metal dissolution at the anode (left electrode) and the direction of current flow. Figure 2.3a shows metals Mi and Mj as the anode and cathode, respectively. Both are immersed in their own sulfate-base electrolyte. Each Mi - MiSO iaq) and M2 - M%SOi aq)... 

The control experiment in pure supporting electrolyte (dotted lines in Fig. 13.2) shows a sharp faradaic current spike, which is mainly due to pseudocapacitive contributions (adsorption of (bi)sulfate and rearrangement of the double layer) plus oxidation of adsorbed Hupd (dotted lines in Fig. 13.2a), but no measurable increase in the CO2 partial pressure (m/z = 44 current) above the background level (dotted lines in Fig. 13.2b). Therefore, a measurable adsorption of trace impurities from the base electrolyte can be ruled out on the time scale of our experiments. Moreover, this experiment also demonstrates the advantage of mass spectrometric transient measurements compared with faradaic current measurements, since the initial reaction signal is not obscured by pseudocapacitive effects and the related faradaic current spike. 

Table 3. Technical Characteristics of LR2325-size MnOz-Li and 1142-size Mn02-Zn cells based on Mn02 synthesized electrochemically from manganese sulfate-containing electrolytes with additions of fluoride ion.

Acid based electrolytes are desirable, as the mobility of protons allows the use of more dilute solutions. However, acids promote hydrogen evolution, which can form bubbles in the cell. Good results with both sulfate and perchlorate salts have been seen. Recent results with chloride in the deposition of CdTe are encouraging as well [142]. 

As already shown by the early work of Clavilier et al. [153], the voltammetric response of Pt(l 11) depends strongly on the nature of the ions in solution. The adsorption states observed in the potential region between 0.4 and 0.9 V of a voltammogram measured in a fluoride solution (Fig. 46 a) characterize the absence of specifically adsorbed ions. In the presence of sulfate species these states are shifted cathodically, as observed in the voltammogram taken in the fluoride base electrolyte after addition of 2.5xl0 M H2SO4 (Fig. 46b). 

Figures 47 and 48 show spectra taken at different potentials in sulfate solutions containing a fluoride base electrolyte at pH 2.8 (0.5 M KF-I-0.69M HF) and 0.23 (7.3 M HF) respectively. Positive-going bands represent the solution loss of species being adsorbed. Negative-going bands are due to the adsorbate.

Alkali metal sulfates [11,12], Ag-(5 -alumina [13], Na-fJ-alumina [14], NASICON (NajZrjSijPOj,) [15], MgO-stabilized [16,17], sulfate-based solid electrolytes [15]... 

Considering water based electrolytes, Grimes et al. [34] achieved the best results (i.e., nanotubes up to 6 pm long) in a solution containing either fluoride salts (NaF or KF) or HF in the presence of buffer salts like sodium sulfate or sodium or potassium hydrogen phosphate in a pH interval ranging from 3 to 5 (Fig. 19). 

The viscosity of aqueous solutions of ether sulfates can be increased by adding an electrolyte, usually common salt. This effect depends on salt concentration and the structure of the particular ether sulfate. As a general rule, it can be said that this thickening effect will happen at lower concentrations of salt, the more branched parts there are in the alkyl chain. This means, in practice, that thickening of solutions of alkyl ether sulfates based on oxoalcohols with a proportion of branched alkyl chains will occur at lower concentration of salt than is the case for alkyl ether sulfates based on pure linear alcohols. The increase of viscosity by the addition of salt also takes place in mixtures of ether sulfates with other types of surfactants. 

Leventis, N. and Y.C. Chung. 1992. New complementary electrochromic system based on poly-pyrrole-Prussian Blue composite, a benzylviologen polymer, and polyfvinylpyrrohdone)/ potassium sulfate aqueous electrolyte. Chem Mater 4 1415-1422. 

Commercially pure nickel cathode is produced by electrowiiming in either sulfate or chloride electrolyte, or a combination of both. Chloride based electrolyte systems generate chlorine gas at the anode The nickel industry to developed anode bag technology in order to capture chlorine gas at the source. Not only is the chlorine gas collected and removed from the operating environment in the cellhouse using anode bags, it is also returned upstream as an oxidant in the matte leaching process step. 

Although the use of additives in the electrolyte is a simple way of improving performances, research into new solvents and salts should not be neglected, as recently demonstrated in copper sulfate-based electrodes for which the use of an ether-based electrolyte (e.g. 1 M lithium... 

SO2 produced by this process can be scrubbed using aqueous NaOH or (NH4)0H solutions to form Na2S03 or (NH4)2SOg solutions. Aqueous sulfite solutions can be further oxidized via electrolytic or photolytic processes, producing sulfate based fertilizer and hydrogen according to ... 

The principle of the SO2 gas detection with the sulfate-based solid electrolyte, is as follows. Two compartments, each with a different SO2 gas concentration, are divided by the solid electrolyte. 

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