Cathodic Ratio Research Articles

In-situ plasma assisted lithium-ion battery cathodes to catalytically pyrolyze lignin for H2-rich syngas production

In-situ plasma assisted lithium-ion battery cathodes catalysis was investigated to pyrolyze lignin to H2-rich syngas, oil and char. The effects of temperature, cathode to lignin ratio and plasma current on syngas production were investigated by using the typical ternary cathode NCM111 (LiNi1/3Co1/3Mn1/3O2) as catalyst and adopting dielectric barrier discharge mode. Response surface methodology based on BOX-BEHNKEN design was used to analyze the significance and interactions of process factors on the syngas yield. The conditions of 837℃, 10.4 %, and 185 mA for obtaining high-yield syngas (22.58 %) were more stringent; thereinto, from high to low, the intensity of factors on the yield was temperature, plasma current, and cathode ratio. Furthermore, different cathodes (non-cathode, NCM811 (LiNi4/5Co1/10Mn1/10O2), LCO (LiCoO2), and LMO (LiMn2O4)) were applied to decouple the catalytic effects of three metals in the NCM111. NCM111 enhanced both lignin gasification and carbonization by reducing condensable components, and NCM811 further improved gasification, but LCO and LMO had weaker gasification ability. NCM111 increased H2 volume fraction from 22.35 % to 67.31 %, NCM811 elevated the micro-discharge performance, promoting the hydrogasification reactions between energetic H species and char to produce more CH4, while LCO and LMO tended to produce the CO-rich syngas. Besides, in-situ plasma and its synergy with cathodes inhibited the formation of heavy aromatics and produced some high-value bio-oils rich in light aromatics, in which NCM111 achieved 92.30 % selectivity towards MAHs. High Ni ratio was beneficial for improving the char porosity, and the chars obtained by using NCM811 had a surface area of 409.29 m2/g, and a pore volume of 0.401 cm3/g. Comparably, the degree of catalytic lignin gasification for preparing H2-rich syngas could be ranked as Ni > Co > Mn in the ternary cathode.

Investigation on the arc root characteristics of vacuum arc between the iron-core cup-shaped transverse magnetic field contacts

The severity of the contact surface ablation determines the breaking capacity of the vacuum circuit breaker, and the interaction between the arc root and the electrode is the main cause of the contact surface ablation. The characteristics of the arc root determine the magnitude of the electromagnetic force received by the arc during the movement stage as well as the shape and speed of the arc movement. It will eventually affect the temperature of the contact surface and the ablation situation. This paper studied the arc root characteristics of high-current constricted vacuum arcs between the iron-core cup-shaped transverse magnetic field contacts and put forward the idea of using the ratio of cathode and anode arc root areas to quantitatively analyze the concentration of vacuum arc. The research on the arc root characteristics of the vacuum arc can help to improve the arc characteristics and arcing mechanism, and the proposition of the ratio can provide a new method for the study of constricted arc. This can provide a basis for improving the arc extinction performance of the switch, reducing the ablation of the contact material, and improving the contact life.

Compost Solid-phase Microbial Fuel Cell (CSMFC) Performance using Graphene and Graphite as Electrodes

Organic waste is a type of waste produced by many sector, which need to managed appropriately. During its development, composting is one of the organic waste management efforts that is often be applied, Another alternative organic waste management in the form of Microbial Fuel Cell (MFC) has emerged. Several researchers conducted studies on MFC performance which was influenced by many factors, especially the electrode which contributes to the electron transfer process. This study has a concern about energy optimization through CSMFC technology using different electrode’s material. Electrode materials from Graphene and Graphit has good electro-conductivity and has a large surface area, making it suitable for bacteria to adhere. The sampled reactors are consists of two types of electrodes in the form of graphite and graphene. Each materials has anode and cathode ratio of 1:1, 2:1, and 3:1. The samples measured into three kinds, which called a mature compost measurement, electrochemical measurement, and biochemical measurement. Some collected sampling data were then processed and analyzed statistically using SPSS software. The processed and analyzed data included the calculation of power density, total N, C/N ratio, and moisture content. Any data like voltage (V) and electric current (I) are needed to obtain a power density. The highest average voltage, current, power and power density are produced by the N3 reactor (graphene 3:1) that is 269 x 10-3 V, 163 x 10-6 A, 56 x 10-6 Watt and 1.914 x 10-3 W / m2. There is no significant effect of variations in the type of electrode (graphite and graphene) on CSMFC performances.

Mass transfer characteristics of a flow-by fixed bed electrochemical reactor composed of vertical stack stainless steel screens cathode

Mass transport properties of a flow-by fixed bed electrochemical reactor composed of a vertical stack of stainless steel nets operated at a batch-recycle mode were characterized using cathodic deposition of copper as a test reaction. The electrochemical reactor was operated at constant potential in which reduction of copper happened under mass transport control. This potential was selected from the application of hydrodynamic voltammetry using a borate/chloride solution as supporting electrolyte on stainless steel rotating disc electrode. A linear relationship was observed between the flow rate and the mass transfer coefficient. The electrochemical reactor was efficient in removing copper and able to reduce the levels of this metal to lower than 0.4 ppm starting from an initial concentration of 49.7 ppm at 80 min using a ratio of cathode volume/catholyte volume equal to 0.0075. A mathematical correlation between the Sherwood number and Reynolds number were obtained which characterized the mass transport properties of the reactor as follows: Sh = 0.2254Re0.4228Sc1/3.

Influence of sea mud state on the anodic behavior of Al-Zn-In-Mg-Ti sacrificial anode

The influence of sea mud state on the anodic behavior of Al-Zn-In-Mg-Ti sacrificial anode was investigated by the methods of electrochemical, immersion and surface analysis techniques. In this work, the simulated seawater, sea mud and seawater/sea mud transition region systems were set up in laboratory, it can measure the galvanic corrosion of sacrificial anode in seawater/sea mud transition environment. Results show that the corrosion rate of Al-Zn-In-Mg-Ti sacrificial anode in simulated seawater is higher than that in simulated sea mud. And the corrosion rate increased with the increasing size of sea mud. When the Al-Zn-In-Mg-Ti sacrificial anode and Q235 joint together at the ratio of cathode and anode area of 50:1, the mix potential shift negative with the increasing size of sea mud and the mixed current density is highest in seawater and increase with the increasing size of sea mud. The corrosion rate is determined by the conductivity and dissolved oxygen in various mud size. In simulated seawater environment, Al-Zn-In-Mg-Ti sacrificial anode present relatively uniform dissolution; however, in simulated sea mud environment, due to the different dissolved oxygen in various mud size, Al-Zn-In-Mg-Ti sacrificial anode present nonuniform dissolving, especially in simulated lager particles sea mud.

Electrolytic removal of zinc from simulated chloride wastewaters using a novel flow-by fixed bed electrochemical reactor

The cathodic deposition of zinc from simulated chloride wastewater was used to characterize the mass transport properties of a flow-by fixed bed electrochemical reactor composed of vertical stack of stainless steel nets, operated in batch-recycle mode. The electrochemical reactor employed potential value in such a way that the zinc reduction occurred under mass transport control. This potential was determined by hydrodynamic voltammetry using a borate/chloride solution as supporting electrolyte on stainless steel rotating disc electrode. The results indicate that mass transfer coefficient (Km) increases with increasing of flow rate (Q) where .The electrochemical reactor proved to be efficient in removing zinc and was able to reduce the levels of this metal to lower than 0.7 ppm starting from initial concentration of 48.4 mg dm-3 ppm in 120 minutes using ratio of cathode volume/catholyte volume equal to 0.0075. Sherwood and Reynolds numbers were correlated to characterize the mass transport properties of the reactor as follows:

Composite organic radical–inorganic hybrid cathode for lithium-ion batteries

A new organic radical–inorganic hybrid cathode comprised of poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PTMA)/LiFePO4 composite system was developed and reported for the first time. The hybrid electrodes' voltammetry contains three pairs of reversible redox peaks indicating the combination of electrochemical characteristics between LiFePO4 and PTMA electrodes and shows a decrease in voltage gap between oxidation and reduction that corresponds to an improvement in the rate and reversibility of the redox couples. Results from electrochemical impedance spectroscopy show lower charge-transfer resistance of cycled hybrid cathodes suggesting an enhanced electrode/electrolyte interface formed in hybrid systems which leads to faster migration of Li ions through the interface and longer cycle life capability when compared with pure LiFePO4 or PTMA cathode system. Optimizing the hybrid cathode's ratio of PTMA/LiFePO4 yields a significant improvement in high pulse power performance (30 mAh cm−3) over the pure PTMA (16 mAh cm−3) or LiFePO4 (3.0 mAh cm−3) cathode. Further characterization of the hybrid electrodes using SEM showed a more compact surface morphology after high rate pulse experiments. The demonstrated properties of hybrid cathodes are promising for transportation and other high pulse power applications that require long cycle life and low cost.

Electrotechnology of microarc oxidation of light alloys

Features of electrotechnology of microarc oxidation of light (Al, Mg, Ti) alloys are considered. A module with current displacement effect was developed and described. It allows to control the ratio of cathode and anode currents and the rigidity of mode in condensing AC inverters which are widely used for this technology.

Kinetics of the Charge/Discharge Characteristics of Redox Flow Battery Electrolytes

A comparison of the electrochemical behavior of Ce(IV) and its complexes of ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminedisuccinic acid (EDDS), and nitrilotriacetic acid (NTA) using cyclic voltammetry (CV) and rotating disc electrode (RDE) on Pt-electrode were carried out. All complexes had an anodic cathodic ratio greater than 1. The Ce(IV)-DTPA had the best properties: highest peak potential, better reversibility, and higher peak current. Potential usage of the Ce(IV)-DTPA in redox flow batteries (RFB) was confirmed by the electrochemical impedance spectroscopy results: lowest electrolyte and charge transfer resistance. The performance evaluation of RFB employing Ce(IV) and Ce(IV) complexes of DTPA and EDTA with constant current charge/discharge analysis proved that CE(IV)-DTPA complex has a potential as an anode in RFB. A maximum potential of 1 V and a minimum voltage of 2 V were achieved. Highest energy, voltage, and coulombic efficiencies of 85%, 93%, and 92% were obtained, respectively.

Intercalation of PF 6− anion into graphitic carbon with nano pore for dual carbon cell with high capacity

Intercalation property of PF 6 − into graphitic carbon was studied for a hybrid capacitor with different ratio of cathode and anode amount. Graphene sheet distance increased with increasing PF 6 − intercalation amount and it saturated at 0.4 nm at high applied potential, which is corresponded to stage 2 structure. On the other hand, it was found that nano size pore into graphene sheet was introduced at higher applied potential with 20 times larger anode carbon and this nano porous carbon shows a large capacity for intercalation capacity of 147 mAh g −1. The estimated energy density of the hybrid capacitor using carbon with nano bubble structure was ca. 400 Wh kg −1.

Research on Corrosion Resistance of Mg-Al-Sr Alloy

The corrosion properties of Mg-Al-Sr alloy was characterized with comparison to AZ91D alloy. With the addition of Mg-Sr master alloy, the grain size of Mg alloy refined and the corrosion resistance was improved. The experimental results indicated that the formation of small amount of Al4Sr phase was favorable to improve the corrosion resistance. However, with the increase of Al4Sr stripy phase, the area ratio of cathode to anode will increase, resulting in the decrease of corrosion resistance potential.

Noniterative method for the synthesis of convergent pierce electron guns

A simple noniterative method has been proposed to design a convergent Pierce electron gun. The logarithmic value of the ratio of cathode to anode radii of curvature is expressed in a power series directly in terms of beam convergence ratio. This made it possible to calculate the half-beam cone angle with the help of Langmuir-Blodgett's solution, which, in turn, facilitated the calculation of other output parameters. The throw of the gun is also expressed in a power series in terms of the ratio of the anode-aperature radius to the beam waist radius. It is numerically shown with practical examples that both the interelectrode distance and the throw decrease with the gun perveance and increase (the former almost linearly while the latter almost binomially) with the beam diameter.

The matching of Pierce guns to tunnels

All Pierce guns which shoot the maximum electron current through two identical apertures collinear with the axis of the gun have a unique ratio of cathode to anode radius. The value of this unique ratio is given for four important cases. A simple design procedure and relevant numerical data are given.