The electrochemical properties of
N
-substituted salts of 2,2'-bipyridine:
N
-methyl-2,2'-bipyridinium iodide and
N
,
N
'-dimethyl-2,2'-bipyridinium iodide were studied by cyclic voltammetry (CV). ...The electrochemical properties are greatly affected by the methyl substituents at the nitrogen atom in the
ortho
-bipyridine molecule. The conproportionation constants were calculated for
N
,
N
'-dimethyl-2,2'-bipyridinium iodide and made it possible to judge about the degree of electron localization in the systems.
To enhance the corrosion resistance of pure aluminum in sulfur-containing environments, Ni–Mo coatings were deposited on aluminum substrates via direct current (DC) and pulse current (PC) ...electrodeposition techniques. The phase structure, micromorphology and element composition of the coatings were characterized by XRD, SEM, and EDS. The corrosion resistance of pure aluminum and Ni–Mo coatings in 1 wt % Na
2
S aqueous solution were studied by static corrosion immersion and electrochemical test. The results indicated that aluminum suffered severe corrosion in Na
2
S aqueous solution, leading to the formation of Al(OH)
3
. The application of Ni–Mo coatings effectively prevented direct contact between the solution and the aluminum substrate. Compared with the coating prepared by DC electrodeposition under the same conditions, the Ni–Mo coating obtained through PC electrodeposition exhibited finer grains, a more compact and flatter surface, and higher Mo content, the impedance value was 15.61 kΩ cm
2
and its corrosion current density was 9.610 × 10
–6
A/cm
2
. The corrosion current density of the coating prepared by DC electrodeposition was 1.514 × 10
–5
A/cm
2
, whereas that of pure aluminum in the same medium was 3.030 × 10
–3
A/cm
2
.
Perovskite based materials have become an attractive anode for fuel cell due to the significant conductivity, carbon resistivity and sulphur tolerance. Doping of Ce on B-site of the La
0.4
Sr
0.6
Ce
...x
Ti
1−
x
O
(
x
= 0.02, 0.04, 0.06, 0.08) with different dopant concentrations is prepared using sol-gel technique. The synthesized material is analyzed by numerous techniques. X-ray diffraction confirmed the cubic perovskite structure (JCPDS 01-079- 0183) with average crystallite size of 35 nm. UV–Vis spectroscopy revealed the red shift in band gap (2.76 eV) compared to LaSrTiO
. Scanning electron microscopy shows the homogeneity and porosity in the prepared material. The observed particle size is in the range of 50–60 nm. The presence of the lanthanum, strontium, cerium, titanium and oxygen ions is confirmed by EDX. The Raman spectra and XRD, confirmed that cerium ions have been diffused in the lattice structure of LSTO
. The La
0.4
Sr
0.6
Ce
0.08
Ti
0.92
O
anode showed the highest conductivity of 2.67 S cm
–1
with lower activation energy of 0.20 eV as compared to other three samples. The power density of 58 mW cm
–2
at 600°C with 0.9 V OCV is achieved for the composition La
0.4
Sr
0.6
Ce
0.08
Ti
0.92
O
using sub-bituminous fuel. The observed results show that prepared material is potential ceramic anode for direct carbon fuel cell.
Hydrogen is considered an appealing fossil fuel alternative due to its high-energy density, environmental friendliness, and reproducibility, but stable, effective, and secure hydrogen storage ...continues to be a major challenge. We synthesized magnesium composites doped with 2 wt % graphene, carbon black, or graphite by the mechanical ball milling method. The effects of various carbon materials on the morphology, phase structure, hydrogen uptake and release properties, and thermal decomposition of magnesium-based composites were investigated by XRD, PCT, SEM, and TG-DSC. The experimental findings show that among the various carbon additives, the hydrogen uptake and release abilities of the carbon black modified magnesium composites were the most notable, followed by graphene and graphite. At 623 K, the carbon black modified Mg composites can absorb 5.78 wt % and desorb 5.51 wt % of hydrogen, respectively. Moreover, the incorporation of carbon black greatly reduced the dehydrogenation peak temperature of MgH
2
. The results indicated that carbon black was instrumental in optimizing the hydrogen storage performance of Mg.
In this work, Ca-doped lithium manganese oxides Li
0.98
Ca
0.02
Mn
2
O
4
were successfully synthesized via a facile hydrothermal method followed by calcination. The evolution of the microstructures ...and electrochemical performance were investigated in detail. XRD identified that pure spinel phase with the enlarged lattice constants were observed in Ca-doped samples. SEM revealed that powders had a hollow hemispherical morphology composed of stacked nanoparticles. Ca doping can improve the electrochemical performance of LiMn
2
O
4
. Galvanostatic charge-discharge tests demonstrated that Li
0.98
Ca
0.02
Mn
2
O
4
calcined at 550°C could deliver the initial discharge capacity of 108.6 mA h/g with the capacity retention of 91.4% after 100 cycles at 2 C. The results indicate that Ca-doped LiMn
2
O
4
is a promising cathode material.
Ordered polyaniline/carbon fibers (PANI/CFs) hybrids were fabricated via a facile in-situ polymerization method, and applied as electrode materials for supercapacitors. The morphology and structure ...of the as-prepared samples were conducted using SEM, XRD, FT-IR, and TGA techniques, respectively, and characterization results proved the successful growth of PANI on the CFs with network structure. The electrochemical performance tests demonstrated that the specific capacitance of PANI/CFs was 653.8 F/g at 1 A/g, and after 2000 cycles, the specific capacitance retained 91.7% at 20 A/g in 1.0 M H
2
SO
4
electrolyte. In comparison to PANI, the excellent electrochemical performance of PANI/CFs was attributed to high dispersion of active sites, good electrical conductivity and enhanced accessibility between electrolyte and the active materials on the electrode. Thus, the improved electrochemical properties of PANI/CFs hybrids suggest good potential to be a greatly promising electrode material for use in supercapacitors.
LiNi
0.5
Co
0.2
Mn
0.3
O
2
(NCM523) cathode materials are susceptible to irreversible phase changes and surface side reactions between electrode materials and electrolyte during charging and ...discharging, which represent a severe danger to the safety and electrochemical performance of batteries. Li
Na
x
Ni
0.5
Co
0.2
Mn
0.3
O
Cl
y
cathode materials co-doped with Na
+
and Cl
–
were prepared by a simple co-precipitation method. The effects of crystal structure, morphology and electrochemical properties were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and charge-discharge performance tests. The results show that the doping of Na
+
and Cl
–
reduces the mixing of cations and expands the diffusion channels of Li
+
. Currently, the doped 1%-NCM has a high charge-discharge capacity and the best cycling performance (187.56 mA h g
–1
at 1 C with the highest capacity retention at 76.29% after the first cycle). After 50 cycles, the specific capacity retention was 138.33 mA h g
–1
, which increased the capacity retention by 18.58% compared with the unmodified material, indicating that the co-doping of anions and cations improved the Li
+
de-embedding ability as well as the specific capacity.
Nitrogen plasma-doped SiO
2
@TiO
2
composites were prepared by plasma-enhanced chemical vapor deposition (PECVD). SiO
2
@TiO
2
with a core-shell structure was first synthesized by the sol-gel method. ...SiO
2
was used as a precursor, followed by coating with TiO
2
film. The core-shell design of SiO
2
@TiO
2
enables the material to withstand large volume changes while maintaining the stability of the solid electrolyte interface (SEI) film. Moreover, nitrogen plasma sputtering introduced numerous oxygen vacancies in the SiO
2
@TiO
2
material, significantly enhancing the battery’s electrical conductivity. The SiO
2
@TiO
2
-N composite exhibited an initial discharge capacity of 1043 mA h g
–1
at a current density of 100 mA g
–1
. After 300 cycles, it still maintained a high discharge capacity of 571 mA h g
–1
.
The relationship between the discharge characteristics of reserve chemical power sources of the lead–perchloric acid–lead dioxide system and the physicochemical properties of electroplated cathode ...coatings with lead dioxide, including phase composition and microstructure, has been studied. The study reveals that the discharge characteristics of power sources can be enhanced by employing a two-layer lead dioxide coating consisting of a porous outer layer and a denser inner layer. The findings have been validated through the production and testing of industrial prototypes of pilot miniature reserve power sources, which exhibit improved performance even at low temperatures (activation time, less than 30 ms; discharge capacity, ~200 mA min/cm
2
; discharge voltage per cell, 1.8–1.2 V at –50°C).
Magnesium alloy has been extensively used in various fields due to prominent physical and chemical properties. Nevertheless, the further application is still impeded by inferior corrosion resistance. ...Herein, a triethanolamine (TEA)-assisted phosphating coating strategy is presented to protect bare magnesium alloy and specifical optimization effect is investigated in detail. Electrochemical tests demonstrate that the addition of TEA significantly enhances the protective performance of phosphating coating. Further, surface analysis indicates that the modified phosphating coating primarily consisting of CaHPO
4
⋅2H
2
O is more uniform and denser owing to the excellent crystallinity of CaHPO
4
crystals with the presence of TEA, which can be ascribed to the destructive effect of H
2
bubbles evolution on the deposition of CaHPO
4
crystals and the alleviated compactness of phosphating coating due to the inhibitive effect of TEA on the galvanic corrosion between α-Mg and β-Mg
17
Al
12
phases. This work intensively reveals the modification mechanism of TEA on the corrosion resistance of phosphating coating, and provide a theoretical guidance for screening suitable organic additives.
