Anode carbon sizing

In this context, a review is presented of the complex chain of events affecting anode performance, ranging from the properties of precursors for filler cokes and binder pitches, through production of these raw materials and their fabrication into anode carbon, and concluding with anode performance evaluation in full-size prebake and Soderberg cells of different designs. 

This ideal carbon should also be as pure as is practical, and have the required electrical conductivity and mechanical strength to function as plant anode material. Anode carbon consists of three elements (1) graphite crystallites in various sizes, shapes, and... 

Coke for the aluminum industry must be calcined before use to produce quality anode carbon. This calcined coke should be relatively hard, strong, dense, with low electrical resistivity and oxidation sensitivity, high purity, and available in aggregate sizing from -1 inch particles to cover standard anode filler sizing requirements. The desired range of property values is as as given in Table I. 

The objective of making good anode carbon, which has the property values already specified, involves four important operations which are applied differently for Soderberg and prebake anode fabrication. These four operations are (1) filler aggregate sizing (2) paste pitching level determination, (3) paste compaction, and (4) compacted composite baking. 

The anodic oxidation of phenol (dissolved in sodium sulfate) was studied by De Sucre and Watkinson using two types of lead dioxide anodes [26]. The first was made of 2 mm lead shot that was oxidized for 12 h at 526mA/cm in 20% sulfuric acid while the second anode, electrodeposited lead dioxide flakes, was supplied by a commercial manufacturer. The phenol oxidized faster on the electrodeposited Pb02, which also turned out to be more corrosion-resistant than the oxidized lead shot. While all of the phenol oxidized rapidly (1.5 h) on the electrodeposited anode, not all of it formed CO2. It was found that 80% of the total organic carbon remained in solution after the phenol was completely oxidized. Phenol destruction increased with an increase in current density, and decreased as electrolyte flowrate, pH, and anode particle size were increased. 

For Sm, Eu, and Yb, on the other hand, nanocapsules containing carbides were not found in the cathode deposit by either TEM or XRD. To see where these elements went, the soot particles deposited on the walls of the reaction chamber was investigated for Sm. XRD of the soot produced from Sm203/C composite anodes showed the presence of oxide (Sm203) and a small amount of carbide (SmC2). TEM, on the other hand, revealed that Sm oxides were naked, while Sm carbides were embedded in flocks of amorphous carbon[12J. The size of these compound particles was in a range from 10 to 50 nm. However, no polyhedral nanocapsules encaging Sm carbides were found so far. 

The physicochemical properties of carbon are highly dependent on its surface structure and chemical composition [66—68], The type and content of surface species, particle shape and size, pore-size distribution, BET surface area and pore-opening are of critical importance in the use of carbons as anode material. These properties have a major influence on (9IR, reversible capacity <2R, and the rate capability and safety of the battery. The surface chemical composition depends on the raw materials (carbon precursors), the production process, and the history of the carbon. Surface groups containing H, O, S, N, P, halogens, and other elements have been identified on carbon blacks [66, 67]. There is also ash on the surface of carbon and this typically contains Ca, Si, Fe, Al, and V. Ash and acidic oxides enhance the adsorption of the more polar compounds and electrolytes [66]. 

The effects of dispersion of the electrocatalyst and of particle size on the kinetics of electrooxidation of methanol have been the subject of numerous studies because of the utilization of carbon support in DMFC anodes. The main objective is to determine the optimum size of the platinum anode particles in order to increase the effectiveness factor of platinum. Such a size effect, which is widely recognized in the case of the reduction of oxygen, is still a subject of discussion for the oxidation of methanol. According to some investigators, an optimum of 2 nm for the platinum particle size exists, but studying particle sizes up to 1.4 nm, other authors observed no size effect. According to a recent study, the rate of oxidation of methanol remains constant for particles greater than 4.5 nm, but decreases with size for smaller particles (up to 2.2 nm). 

Commercial and non-commercial carbons were tested for their applicability as anode of lithium-ion battery. It was found that Superior Graphite Co s materials are characterized both by high reversible capacities and low irreversible capacities and thus can be regarded as good candidates for practical full cells. Cylindrical AA-size Li-ion cells manufactured using laboratory techniques on the basis of SL-20 anode had initial capacities over 500 mAh (volumetric energy density ca. 240 Wh/dm3). Boron-doped carbon... 

There is no question that the development and commercialization of lithium ion batteries in recent years is one of the most important successes of modem electrochemistiy. Recent commercial systems for power sources show high energy density, improved rate capabilities and extended cycle life. The major components in most of the commercial Li-ion batteries are graphite electrodes, LiCo02 cathodes and electrolyte solutions based on mixtures of alkyl carbonate solvents, and LiPF6 as the salt.1 The electrodes for these batteries always have a composite structure that includes a metallic current collector (usually copper or aluminum foil/grid for the anode and cathode, respectively), the active mass comprises micrometric size particles and a polymeric binder. 

Further on, the Co-Ni complexes were used for modification of Hohsen Carbon type (10-10) and Hohsen Graphite type (10-28) anode materials for Li-ion batteries applying similar procedure. These anode materials were tested in 2016 size lithium coin cells with a configuration Li/electrolyte (LP-30)/(modified anode material). The coin cells were assembled by standard technology in dry atmosphere of a glove box and then... 

Various nanoporous AAO membranes have been obtained by varying different parameters such as applied voltage, temperature of electrolyte, electrolytic concentration and speed of rotation of electrolyte in two step anodization process. SEM analysis performed for evaluation of results. The relationship between pore size and variation of different parameters obtained. The synthesized membranes have been used as template for the synthesis of carbon nanotubes of different nano dimensions. 

A similar approach for the production of hydrothermal carbon nanotubes is the hydrothermal carbonization of glucose in the macrochannels of anodic alumina membranes [16]. Depending on the pore size of the membrane different hollow hydrother-... 

Another important parameter that has to be taken into account when choosing the appropriate diffusion layer is the overall cost of the material. In the last few years, a number of cost analysis studies have been performed in order to determine fuel cell system costs now and in the future, depending on the power output, size of the system, and number of xmits. Carlson et al. [1] reported that in 2005 the manufacturing costs of diffusion layers (for both anode and cathode sides) corresponded to 5% of the total cost for an 80 kW direct hydrogen fuel cell stack (assuming 500,000 units) used in the automotive sector. The total value for the DLs was US 18.40 m-, which included two carbon cloths (E-TEK GDL LT 1200-W) with 27 wt% P ILE, an MPL with PTFE, and Cabot carbon black. Capital, manufacturing, tooling, and labor costs were included in the total. 

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