Ionics
Spherical LiNi1/3Co1/3Mn1/3O2 was successfully prepared by controlled crystallization. The preparation started with the spherical coprecipitate of Ni1/3Co1/3Mn1/3CO3 from NiSO4, CoSO4, MnSO4, NH4HCO3, and NH3·H2O, followed by pyrolysis of Ni1/3Co1/3Mn1/3CO3 at 600°C for 3 h. The X-ray diffraction analysis showed that the homogeneous cubic (Ni1/3Co1/3Mn1/3)3O4 was obtained after the pyrolysis. Spherical...
Crystals of the BaBi x O1.5x+1 family are studied using X-ray diffraction, calorimetric, and impedance methods. It is shown that the compounds with x>5 are thermally stable in the temperature range as wide as 300–870 K, in spite of the first-order phase transition with a large heat effect. The conductivity is found to be anisotropic both in low- and high-temperature phases.
Microstructural and chemical changes in a NiO-YSZ electrocatalytic electrode were studied. The microstructural changes in the NiO-YSZ electrocatalytic electrode after the cell operation was compared with the electrode quenched under the applied voltage to suppress the oxidation process. The reversible reduction of NiO into Ni and the formation of intergranular Ni layers at the NiO/YSZ interface were...
Magnetic experiments are powerful tools to study fundamental properties and to check the qualities of samples. Temperature, stress, and impurities of materials can all affect magnetic properties and play an important role in the utilization of these materials for engineering applications. The estimation and analysis of the spontaneous magnetization can reveal ferromagnetic particles as impurities...
The responses to biasing a nickel–metal hydride secondary battery with a dc pulse train, as well as to spontaneous discharging, are studied. A comparison is made between the current during biasing, i e, and the current during off-biasing, i g. It is suggested that both currents arise from the motion of the same charge carriers in the electrolyte, possibly the OH− ions. The only difference is that...
The aim of this work is to enhance the room temperature conductivity of solid alkaline composite polymer electrolytes (ACPEs) based on polyvinyl alcohol/potassium hydroxide/propylene carbonate (PVA–KOH–PC) composites by cross-linking the PVA and bond scission of the PC by γ-radiation. The ACPEs were prepared by solvent-casting technique and irradiated with doses up to 200 kGy at room temperature....
Ionics is a key technology for storing, converting and using energy efficiently as well as protecting the environment. Major progress has been achieved in recent years in the understanding and development of individual materials components needed for ionic devices. It should be emphasized that only combinations of materials are eventually important and at least four interfaces exist with electronic...
Polyvinyl alcohol (PVA) and potassium hydroxide (KOH) have been used to prepare alkaline solid polymer electrolytes (ASPE) films. The films were stored in a dry environment for 30 and 100 days. The highest room temperature conductivity for the PVA:KOH film with weight percentage ratio of 1:0.67 during storage for 30 and 100 days were (8.5±0.2)×10−4 and (1.3±0.1)×10−7 S cm−1, respectively. The conductivity–temperature...
A highly conductive bismuth oxide/ceria bilayer electrolyte was developed to reduce solid oxide fuel cell (SOFC) operating temperatures. Bilayer electrolytes were fabricated by depositing a layer of Er0.2Bi0.8O1.5 (ESB) of varying thickness via pulsed laser deposition and dip-coating on a Sm0.2Ce0.8O1.9 (SDC) substrate. The open-circuit potential (OCP) and ionic transference number (t i) of ESB/SDC...
With dwindling liquid fuel resources, hydrogen offers a credible alternative. The use of hydrogen in a fuel cell offers the highest fuel conversion efficiency compared with all other technologies and it also has the potential to substantially reduce greenhouse gas and particulate emissions at least at the end-user sites. One of the major barriers to the introduction of the hydrogen economy and its...
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It was found for the first time that the catalysis of yttrium doping of spinel LiMn2O4 can enhance the electrochemical activities of manganese, leading to both improvement of electrochemical capacity and reactivity with the electrolyte of manganese. A proper amount of doping was 0.5%, and such yttrium-doped sample, Li(Y0.005Mn0.995)2O4, had an initial capacity of 130 mAh g−1 over that of the undoped...
Iron disulfide reactivity relative to the components of composite polymer electrolytes based on chlorinated polyvinylchloride has been studied by taking differential infrared (IR) spectra. It has been shown that iron-containing admixtures on iron disulfide surface can initiate the decomposition processes of polymer systems. Possibility of diffusion to the volume of liquid electrolyte of surface iron—comprising...
Recent material developments of fast solid oxide and lithium ion conductors are reviewed. Special emphasis is placed on the correlation between the composition, structure, and electrical transport properties of perovskite-type, perovskite-related, and other inorganic crystalline materials in terms of the required functional properties for practical applications, such as fuel or hydrolysis cells and...
Commercial silica gel drying pearls were used in impedance measurements between ambient temperature and 300 °C in dry and humid atmospheres. A pronounced difference was seen supporting previous conclusions that proton conduction was operative in these amorphous samples. The same conclusion was reached on the basis of a fuel cell experiment at ambient temperature. A Nernst voltage close to the theoretical...
There is a global push to develop a range of hydrogen technologies for timely adoption of the hydrogen economy. This is critical in view of the depleting oil reserves and looming transport fuel shortage, global warming, and increasing pollution. Molecular hydrogen (H2) can be generated by a number of renewable and fossil-fuel-based resources. However, given the high cost of H2 generation by renewable...
Capacity fading of LiCr0.1Mn1.9O4 /MPCF (mesophase pitch-based carbon fiber) cells was investigated at elevated temperature (55 °C). The cells showed very fast capacity fading, keeping only 60% of capacity retention at the 100th cycle at 55 °C. The cycled electrodes and the electrolyte were analyzed using electrochemical test, inductively coupled plasma, and X-ray diffraction. Results of the analyses...
Electrical conductivity and dielectric relaxation studies of silver ion-conducting glasses have been prepared using xAg2SO4-15Ag2O-(90-x)(90P2O5-10MoO3) glass system over a temperature range of 298–353 K and frequencies of 10 Hz to 10 MHz. DC conductivities exhibit Arrhenius behavior over the entire temperature range with a single activation barrier. The ac conductivity behavior of these glasses has...