Electrochemical pulsed current

The possibility that adsorption reactions play an important role in the reduction of telluryl ions has been discussed in several works (Chap. 3 CdTe). By using various electrochemical techniques in stationary and non-stationary diffusion regimes, such as voltammetry, chronopotentiometry, and pulsed current electrolysis, Montiel-Santillan et al. [52] have shown that the electrochemical reduction of HTeOj in acid sulfate medium (pH 2) on solid tellurium electrodes, generated in situ at 25 °C, must be considered as a four-electron process preceded by a slow adsorption step of the telluryl ions the reduction mechanism was observed to depend on the applied potential, so that at high overpotentials the adsorption step was not significant for the overall process. 

Pulsed-current techniques can furnish electrochemical kinetic information and have been used at the RDE. With a pulse duration of 10-4 s and a cycle time of 10-3 s, good agreement was found with steady-state results [144] for the kinetic determination of the ferri-ferrocyanide system [260, 261], Reduction of the pulse duration and cycle time would allow the measurement of larger rate constants. Kinetic parameter extraction has also been discussed for first-order irreversible reactions with two-step cathodic current pulses [262], A generalised theory describing the effect of pulsed current electrolysis on current—potential relations has appeared [263],... 

The use of polarographic assays for the determination of drugs in blood is the most demanding on the detection limitations of the technique. Differential pulse polarography, stripping voltammetry, and LCEC are the only electrochemical methods currently available for routine determination of drugs below 1.0 ng/mL of blood. 

S. McGinnis, P. Sines, and B. Das, Pulsed current anodization An effective method for fabricating patterned porous silicon p-njunction light emitting diodes, Electrochem. Solid-State Lett. 2, 468, 1999. 

Hydroxyapatite substituted with metabolic elements such as Sr, Mg and Zn were deposited by pulsed current ECD technique (Gopi et al., 2014). The coatings imparted sufficient corrosion resistance to the Ti alloy substrate and showed potential for suitable cell attachment and proliferation. Addition of single-walled carbon nanotubes (SWCTs) to electrochemically deposited hydroxyapatite increased the coating bond strength to 26 MPa, an improvement of about 70% over that of pure hydroxyapatite (Pei et al., 2014). 

The pick-up of electrical and electromagnetic noise should be avoided, especially in the case of the application of electrochemical pulse methods and sensitive dc measurements involving small potential perturbations and currents. 

Electrochemical deposition of a CP is generally carried out in a single compartment, three-electrode (working, counter, and reference electrodes) cell with a solution of a monomer and an electrolyte (dopant) dissolved in an appropriate solvent. A schematic of a typical electrochemical deposition rig is shown in Figure 18.6. Upon galvanostatic (constant current), potentiostatic (constant potential), or potentiodynamic (pulsed current or pulsed... 

Biochemical analysis on nanoliter scale is precisely carried out by micrototal analysis system (pTAS) which consists of microreactors, microfluidic systems, and detectors. Performance of the pTAS depends on micromachined and electrochemically actuated micropump capable of precise dosing of nanoliter amounts of liquids such as reagents, indicators, or calibration fluids [28]. The dosing system is based on the displacement of the liquid from a reservoir which is actuated by gas bubbles produced electrochemically. Electrochemical pump and dosing system consist of a channel structure micro-machined in silicon closed by Pyrex covered with novel metal electrodes. By applying pulsed current to the electrodes, gas bubbles are produced by electrolysis of water. The liquid stored in the meander is driven out into the microchannel structure due to expansion of gas bubbles in the reservoir as shown in Fig. 11.8. 

Micropump delivery rates are as low as few nl/s and can be controlled accurately by the pulsed current passing through the platinum electrodes. Electrochemical gas production can be precisely... 

Electrochemical machining (ECM) is a material removal process into which pulsed current is dissipated through a conductive electrolytic solution between the tool and the workpiece (Fig. 2). Such chemical interaction causes material to be removed from the workpiece according to the shape of the tool. ECM is based on thermal effects by extremely quick heating, melting, and vaporizing. The heat sources are the energy... 

Metal used Current density [mA cmr ] Electrochemical pulse Time on Time off [ms] [ms] Ultrasonic pulse Time on /imsj Particle size achieved [nm] Current efficiency... 

This is of course not the case when working with room temperature ionic liquid systems. Electrochemical and spectroscopic studies of cobalt, copper, and nickel, have been carried out in the AlClj-butylpyridinium chloride molten salt system. The direct current and pulsed current electrodeposition of Ni-Al alloys has also been shown in acidic AlCls-butylpyridinium chloride ionic liquids. This particular alloy has also been shown to be successful in AlCl3-[C2-mim]Cl ashave Co-Al andCu-Al. Electrochemical techniques can also be used to calculate the diffusion coefficients of metal ions. Table 21.2.6 shows the calculated diffusion coefficients and stokes-Einstein products of cobalt(II), copper(I), nickel(II) and zinc(II) in the 40-60 mol% [Cj-mimlCl-AlClj ionic liquid. 

Employ pulse current deposition method Maximize amount of zinc electrodeposited from electrolyte solution Need to identify optimal deposition conditions, followed by electrochemical tests to characterize improvements in system efficiency... 

MACE has been combined with electrochemical etch to form localized porous segments in nonporous nanowires and obtain nanowires of prescribed length by cleavage at the porous sections (Kim et al. 2011b). A pulsed current is applied to the substrate to induce periodic porosiflcation. Direct contact to a patterned continuous metal film is necessary to induce localized porosiflcation. If the backside of the wafer is contacted, the entire nanowire structure porosifies upon current pulsing. 

Pulse electrodeposition (pulsed potential or pulsed current) has been also employed for CdSe formation [30]. In addition, EC-ALE has been employed for the electrochemical synthesis of CdSe on Au substrates through the layer-by-layer UPD of Se and Cd in sequence [45,46]. 

Thus, we implement robust diagnostic methods, which are as un-intmsive as possible, with a view to management of the battery s operation and predictive maintenance of the components during their operation. These methods are based on electrical or empirical models using measurements of the voltage, current and temperature, and monitoring of the electrical parameters which are representative either of the SOC or the SOH. These electrical parameters are obtained from electrochemical measurements taken by impedance spectroscopy (Sequential measurements described in section 2.4.12) or by pulsed current (temporal measurements) such as the internal resistance. Thermal models on the scale of the element or of the pack are also of crucial importance. ... 

---