The authors worked as working group members in the Molten Salt Committee of the Electrochemical Society of Japan in FY 2015–2016 to collect and summarize information on books and literatures devoted to molten salts. They covered a wide range of aspects of molten salts such as handling/measurement techniques, thermophysical properties, phase diagrams, thermodynamic data, electrochemical data, and structures. A total of 89 books and database literature sources were organized by content. The group also carried out an activity to archive the technical data of the electrolytic smelting of Al metal in the Hall-Héroult process that has operated in Japan. We hope this activity report will allow molten salt researchers to access trustworthy information conveniently.
In this work, [EMIM]F-urea-H2O system is capable of dissolving Cu2O, and then the metallic copper was electrodeposited from this system at room temperature. The reduction of Cu (I) in this system involves a quasi-reversible and one-step single-electron transfer process. The electrodeposition of copper was performed on a tungsten (W) substrate at −0.67 V (vs. Ag) and 353 K via potentiostatic electrolysis. The electrodeposits were identified as metallic copper, as verified by XRD and EDS. SEM image shows that uniform, polygonal nanoparticles of copper were obtained after the potentiostatic static electrolysis.
We, for the first time, fabricated an additive-free battery electrode composed of Fe-zeolitic imidazolate frameworks-derived Fe2O3 nanoparticles (NPs) incorporated in carbon shells (Fe2O3@C) through electrophoretic deposition (EPD). High specific capacity of Fe2O3@C without additives comparable to that of the theoretical capacity (1007 mAh/g) suggests that the electrochemical conversion reactions accompanied by lithiation and delithiation process are not significantly limited by the absence of the conductive agents and binders. The additive-free system paves the way for an efficient experimental probe to investigate the intrinsic electrochemical properties of the metal-organic framework-derived nanostructures.
We fabricated an ultrathin ligand-free lead sulfide (PbS) colloidal quantum dot (CQD) field effect transistor (FET) and probed interfacial charge transport properties sensitized by the combination of gate electric field and ultrathin CQD layer thickness at low temperature. Large gate-modulated current hysteresis of the (NH4)2S-treated PbS CQD FET was significantly reduced at lower temperature. Interfacial charge transport after oleic acid ligand removal of PbS CQDs close to the gate dielectric is investigated through analysis of temperature dependent mobility and threshold voltage, hypothesizing that gate field screening by ionic conduction and thermally-activated electronic transport determine the interfacial charge transport properties.
We show that a catalytic amount of electro-generated acid (EGA) prepared from the oxidation of a Bu4NB(C6F5)4/CH2Cl2 solution catalyzes effectively the tandem cyclization of epoxyolefins, producing the corresponding polycyclized compounds in 23%–57% yields. The scope and limitations of the substrates are examined, and we compare the stability of the intermediates through theoretical calculations. The success of the current reactions might be due to the high reactivity of EGA, because the counter anion is bulky and stabilized B(C6F5)4− derived from Bu4NB(C6F5)4 as the supporting electrolyte.
Previous study shows that tetra-n-hexylammonium cation (THA+), which is composed of one nitrogen atom and four alkyl chains, increases the activity of the oxygen reduction reaction (ORR) on Pt(111) eight times as high as that of bare Pt(111). We have studied the ORR on Pt single crystal electrodes modified with alkane to elucidate which part of THA+ contributes to the enhancement of the activity for the ORR. The ORR activity is increased only twice by the modification of Pt(111) with dodecane and hexadecane. Combination of a nitrogen atom and alkyl chains of THA+ plays an important role in enhancing the ORR on Pt electrodes. Dodecane and hexadecane increases the ORR activity on Pt(111) and Pt(110), but they deactivate the ORR on Pt(100) and the high index planes.
To investigate the effect of catholyte shared by different membrane electrolytic cells on electrosynthesis of ammonium persulfate, the equivalent circuit models of two electrolytic cells with shared catholyte and separate catholyte were established and the pilot experiments were carried out with a cation exchange membrane (named PGN membrane) and the Al2O3 ceramic membrane. The model results showed that there appeared the bias ionic current from the low resistance electrolytic cell to the high resistance electrolytic cell with shared catholyte. The experimental results showed that the cathode current of the PGN membrane electrolytic cell was 56 A lower than its anode current with shared catholyte while the cathode current of the ceramic membrane electrolytic cell was 56 A higher than its anode current at the supply voltage of 5.3 V. And the current efficiency of PGN membrane and the ceramic membrane declined with their energy consumption increasing compared with those with separate catholyte. The model results showed a good agreement with those of the experiments. Therefore, it is necessary to consider the effect of shared catholyte by different membrane electrolytic cells on industrial electrosynthesis of ammonium persulfate.
A novel modification method of stainless-steel electrode for reduction of sulfur dioxide to prepare sulfur was reported. Sulfur dioxide can spontaneously react with modified stainless-steel electrode at a rate of 12.77 mA/cm2 to produce sulfur under acidic conditions without additional energy. Evidence was found for the destruction of passive film on the stainless-steel surface in the process of modification which leads to the open circuit potential of stainless-steel electrode shift negatively to the reduction potential range of sulfur dioxide. When modified stainless steel was used as cathode in electrolysis, the contributions of impressed current and redox reaction made the sulfur yield up to 88% within 3 hours.
Chlorophenols (CPs) are a kind of important organic chemical intermediates, which are produced in various industrial processes. Currently, electrochemical method is the most effective treatment for the degradation of chlorophenols (CPs) in wastewater. In this study, a three-dimensional electrode electrochemical reactor, constructed using the Sn/Sb-Mn-GAC (granular activated carbon) particle electrodes, was used to treat the wastewater containing 4-chlorophenol. On the basis of single factor experiments, the process conditions of the designed three-dimensional electrochemical reactor were optimized using the response surface methodology. The experimental results showed that the three-dimensional electrochemical reactor could effectively reduce 4-chlorophenol by 96.13% at the optimum Na2SO4 concentration of 2 g·L−1, electrode plate distance of 2 cm, current intensity of 2 A, and particle electrode dosage of 14 g. The experimental observations were in reasonable agreement with the modeled values, thus verifying the design of the proposed reactor.
Anode support is prepared using phase inversion method and directly used for anode supported solid oxide fuel cell. The anode substrate is about 560 µm in thickness and has a porosity of 60.0%. The finger-like pore layer is 522 µm in thickness, in which the finger-like pore diameter is about 30 µm. The sponge layer is 28 µm in thickness and has a porosity of 46.1%. The single cell with Ni-YSZ/YSZ/GDC/BaCo0.4Fe0.4Zr0.1Y0.1O3−δ configuration is fabricated with YSZ electrolyte on the skin layer. At 800°C and under an output voltage of 0.64 V, the single cell attains a power density of 3.33 W cm−2. At 700°C, 750°C and 800°C, the single cell outputs a current density over 5.2 A cm−2 without the appearance of limited current density from gas transport. The results depict gas transport in the anode substrate with the sponge layer and the skin layer is highly efficient.
A LiCoO2/LiNi0.8Co0.1Mn0.1O2 composite was prepared by the combination of mechanical ball milling and heat treatment. The as-prepared LiCoO2/LiNi0.8Co0.1Mn0.1O2 composite was characterized by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray Spectroscopy. The LiCoO2/LiNi0.8Co0.1Mn0.1O2 composite was utilized as cathode material for lithium-ion batteries. Compared with the milled LiCoO2/LiNi0.8Co0.1Mn0.1O2 composite, the LiCoO2/LiNi0.8Co0.1Mn0.1O2 composite after heat treatment exhibited superior performance, including in an increased coulombic efficiency, better capacity retention and enhanced rate capability. The present work demonstrated that Ni and Mn from LiNi0.8Co0.1Mn0.1O2 were co-doped for the LiCoO2 during high temperature, resulting in improving the electrochemical properties of the LiCoO2/LiNi0.8Co0.1Mn0.1O2 composite.
The satellite REIMEI was launched in August 2005, this is one of the first satellites to use Li-ion batteries. REIMEI is a small scientific satellite designed for carrying out aurora observations using three different cameras. The main scientific mission of the satellite ended in 2013. More than 14 years have passed, and the batteries have experienced over 78,100 charge/discharge cycles. REIMEI remains in operation with a new mission dedicated to analyzing its Li-ion battery. In this work, we present a durability analysis for the REIMEI battery based on telemetry data.
TiO2(B) has a high theoretical capacity of 335 mAh g−1 for Li+ intercalation and thus has been considered as a candidate for lithium-ion capacitor and Li-ion battery negative electrodes. For high rate lithium storage, i.e. high power density, it is important to shorten the Li+ diffusion path by using nanostructured TiO2(B). In this work, TiO2(B) nanosheet with different equivalent diameter of 300 nm and 30 nm were prepared. In addition, the orientation of the TiO2(B) nanosheets was manipulated by altering the deposition method and drying process. Smaller size TiO2(B) nanosheets had better Li+ intercalation ability compared to larger sized TiO2(B) nanosheets. The effect of alignment of the TiO2(B) nanosheets was evident for small-sized TiO2(B) nanosheets; vertical or random alignment of small-sized TiO2(B) afforded higher capacity compared to horizontally oriented nanosheets.
To control the fluoride dissociation and conduction of polyether-based solid polymer electrolytes, an electrolyte system composed of a host polymer, metal salt, and anion acceptor was proposed. Appropriate choices of metal salt with low lattice enthalpy and anion acceptor concentration were important to obtain polymer electrolytes with high fluoride conductivity. The results of thermal and electrochemical measurements revealed that the optimal electrolyte system displayed a relatively high fluoride conductivity of ca. 1 × 10−6 S cm−1 at 303 K and fluoride transference number of over 0.8 (80%).
The electrochemical reduction of anthracenes in the presence of esters and chlorotrimethylsilane in LiClO4/THF in the undivided cell equipped with magnesium electrodes affords the corresponding cyclized products at low to moderate yields. Herein, the chemical structure of the product is determined by X-ray analysis, as well as 1H NMR, 13C NMR, and HRMS. The in situ generation of magnesium anthracenes is indicated. The scope and limitations of the current reactions using anthracene and its derivatives with various esters are investigated.
We propose a novel “bezel-less” lithium-ion battery (LIB) structure that enhances the volumetric energy density of LIB. This structure reduces the extra-space volume for seal and accumulation of current collectors, eliminating the bezel part by 16% compared to the conventional aluminum laminated LIBs. The bezel-less LIB using a Ni-rich positive electrode and a graphite negative electrode recorded an energy of 132 Wh and high energy density of 600 Wh L−1 (256 Wh kg−1). The safety of the proposed bezel-less LIB by a combined use of the quasi-solid-state electrolyte layer was successfully demonstrated in overcharge and collapse tests.
In order to improve the surface integrity of nitinol cardiovascular stents, this paper presented the method of electropolishing nitinol cardiovascular stents by adding distilled water of different concentration into ethylene glycol - sodium chloride electrolyte to find the optimal electrolyte composition and to investigate the change of surface chemical composition. The I-V curves and surface roughness were measured to determine the optimal polishing voltage range. The optimal polishing voltage and the composition and concentration of electrolyte were obtained by data analysis. Surface integrity of nitinol cardiovascular stents has also improved significantly. In addition, Titanium dioxide film was formed on the surface of the nitinol cardiovascular stents, which played an important role in improving the biocompatibility of the stents.
Rapid quenching is one of the methods for preparing silicide/Si composite alloy as an active material for negative electrode in lithium-ion batteries. In this study, we focused on the method’s control over the positional relation between the Si and silicide phase by changing the additive elements. Various Si-alloys and the relationship between their lithiation and delithiation properties and their arrangement was investigated.
This study details the development of a solid-state complementary metal-oxide semi-conductor (CMOS)-compatible glucose fuel cell, consisting of various amounts (% wt.) carbon nanohorns (CNHs). It was fabricated on an anode area using one-dimensional (1D) structural CNHs, which express an open-circuit voltage (OCV) of 375 mV, the power density of 8.64 µW/cm2 and current density 23.05 µA/cm2 in 30 mM glucose solution. The cell can be manufactured via a CMOS fabrication process, using materials biocompatible with the human body. The CNHs enhanced the fuel cell due to their high electrocatalytic ability. Here, CNHs were used to fabricate a 17.5 mm × 0.7 mm solid-state CMOS-compatible glucose fuel cell with 375 mV of OCV - the highest reported value for such a cell with an anode area of 16.2 mm × 0.3 mm. The highest power is 0.42 µW. Power generation is the main challenge for developing glucose fuel cells to make the implantable devices that can be used for biomedical applications.
In this study, we have demonstrated electrochemical synthesis of polyphenylene (PP) deriving from 1,4-bis(trimethylsilyl)benzene using a flow microreactor. The electrochemical flow microreactor allowed effective synthesis of a soluble PP without its deposition. The molecular weight of PP could be controlled by selecting reaction conditions for the electrochemical polymerization in the microreactor. In addition, the role of trimethylsilyl (TMS) group in this reaction process was clarified by the comparison to the polymerization of unsubstituted benzene.
Commercially available 18650 LiFePO4-Graphite Li-ion cells were exposed to charge-discharge cycling at 0°C following two different charge methods: constant current-constant voltage (CC-CV) and constant current (CC), and two different discharge rates: 1 C and 0.2 C. The effect of the charge method and discharge rate on the cell performance was analyzed. The cell exposed to CC charge and 1 C discharge-rate showed a high voltage plateau at the beginning of the discharge voltage, while a high voltage plateau was not observed in the discharge profiles of the cells exposed to a discharge rate of 0.2 C.