Efficiency electrochemical

Whenever energy is transformed from one form to another, an iaefficiency of conversion occurs. Electrochemical reactions having efficiencies of 90% or greater are common. In contrast, Carnot heat engine conversions operate at about 40% efficiency. The operation of practical cells always results ia less than theoretical thermodynamic prediction for release of useful energy because of irreversible (polarization) losses of the electrode reactions. The overall electrochemical efficiency is, therefore, defined by ... 

Usually the plaques produced by either method are coined (compressed) in those areas where subsequent welded tabs are coimected or where no active material is desired, eg, at the edges. The uncoined areas usually have a Bmnauer-Emmet-TeUer (BET) area in the range of 0.25—0.5 m /g and a pore volume >80%. The pores of the sintered plaque must be of suitable size and intercoimected. The mean pore diameter for good electrochemical efficiency is 6—12 p.m, deterrnined by the mercury-intmsion method. 

Electrochemical efficiency, batteries, 3 414 Electrochemical etching, in membrane preparation, 15 813t Electrochemical ethylene oxidation,... 

Accidental operation with an anolyte total organic concentration (TOC) of 6,000 mg/L (rather than the intended 3,000 mg/L) during a test run of Composition B oxidation demonstrated an electrochemical efficiency of approximately 70 percent versus the target 40 percent. This is consistent with the behavior of the plant during the oxidation of M28 propellant in Demo II. 

The committee notes that other research in mediated electrochemical processes has shown that the coulom-bic or electrochemical efficiency of the process is directly proportional to the concentration of the material being oxidized and rapidly decreases as the destruction approaches 100 percent—that is, as the concentration of oxidizable material becomes very small (Chiba et al., 1995). 

What is the cause of /non-faradaic. ie. why is the electrochemical efficiency lower than the 100% theoretical maximum ... 

In a set of experiments (6), the authors have determined the electrochemical efficiency of Ni/Cu layer deposition. It was found that the copper layers deposit with 96% efficiency and the nickel deposit with 90% efficiency. This information, together with the measured coulomb input per layer, enables one to confirm the validity of the suggested formula. Alternatively, if one accepts the arguments that lead to the formula, the electrochemical efficiency values can be viewed as confirmed. The relatively slight deviation from perfect efficiency, at least in the case of nickel, is probably connected with hydrogen evolution. 

Electrochemical efficiency equal to the number of moles of gaseous products per Faraday. Traces of 17 and 18 were also found. 

Electrochemical efficiency (moles of gaseous products per Faraday). 

Electrochemical efficiency given as the ninnber of moles of 5 decomposed per Faraday. "The ratio of moles of Ar radicals to moles of 5. 

The key to the successful development of this method lies in the development of inexpensive electrodes possessing high electrical conductivity, chemical and physical stability, large selective ion removal capacity, and reasonable electrochemical efficiency. Graphite and carbon-based materials are considered to be the most promising. 

Microreaction technology has already shown a great deal of promises for homogeneous reactions, be thermal, photochemical or electrochemical. Efficient mixing, precise control of reaction temperature and residence time enable one to manipulate the selectivity issue, tame an ultrafast reaction or even conduct a highly exothermic... 

The cost of hydrogen from electrolysis is dominated by two factors (1) the cost of electricity and (2) capital-cost recovery for the system. A third cost factor—operation and maintenance expenses (O M)—adds perhaps 3 to 5 percent to total annual costs. The electrochemical efficiency of the unit, coupled with the price of electricity, determine the variable cost. The total capital cost of the electrolyzer unit, including compression, storage, and dispensing equipment, is the basis of fixed-cost recovery. 

The total cost of a system at this scale would be about 2.5 million. It is anticipated that electrolysis technology scales with an 85 percent factor, so smaller-scale systems, with somewhat higher unit costs, are entirely feasible. For example, a facility with half the fueling capability (60 cars per day) would cost about 1.25 million, plus a 15 percent scaling factor. The scalability of electrolysis is one of the important factors relating to its likely use in early-stage fuel cell vehicle adoption. The electrochemical efficiency of electrolysis is essentially independent of scale. 

Overall, improvements in electrolyzer performance will come from three advancements (1) improved electrochemical efficiency—efficiency gains from 63.5 percent system... 

Reagents The AFCs work only with pure reagents. The presence of impurities and nitrogen reduces the electrochemical efficiency of the cell. The presence of CO2, which reacts easily with the alkaline electrolyte to form carbonates, may be detrimental for the cell, resulting in... 

The simultaneous application of ultrasonic irradiation to an electrochemical reaction which has been termed sonoelectrochemistry has been shown to produce a variety of benefits in almost any electrochemical process. These include enhanced chemical yield in electrosynthesis and the control of product distribution improved electrochemical efficiency in terms of power consumption, improved mixing, and diffusion in the cell minimization of electrode fouling accelerated degassing and often a reduction in the amount of process-enhancing additives required. In a major chapter devoted to this topic, Suki Phull and Dave Walton have attempted to cover the majority of applications of ultrasound in electrochemistry including electrochemical synthesis, electroanalytical chemistry, battery technology, electrocrystallization, electroinitiated polymerization, and electroplating. 

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