The electrochemical hydrogenation of soybean oil with supercritical carbon dioxide (SC‐CO2) has been studied to seek ways for substantial reduction of the trans fatty acids (TFA). The solubility of CO2 in electrolytes and the conductivity of electrolytes were investigated using a self‐made electrochemical hydrogenation reactor. The optimum hydrogenation parameters were assessed. Both the solubility of CO2 in electrolytes and the conductivity of electrolytes increased with increasing CO2 pressure. When the pressure reached a critical point of CO2, the solubility of CO2 expressed as a mole fraction was 0.42 in cathode electrolyte and 0.1 in anode electrolyte. At 8 MPa, the conductivity of electrolytes was 1.5 times higher than that at 2 MPa. When the pressure was higher than the critical point of CO2, the solubility of CO2 in electrolytes and the conductivity of electrolytes reached a stable value. The optimum condition for electrochemical hydrogenation of soybean oil in SC‐CO2 were reaction pressure (8 MPa), reaction temperature (48 °C), current (125 mA), agitation speed (300 rpm), and reaction time (8 h). Fatty acid profile, iodine value, and TFA content were evaluated at the optimum parameters. This investigation showed that the electrochemical hydrogenation of soybean oil in SC‐CO2 was improved. The reaction time was shortened by 4 h, and TFA content was reduced by 35.8% compared to traditional hydrogenation process. 相似文献
All‐solid‐state lithium‐ion electrolytes offer substantial safety benefits compared to flammable liquid organic electrolytes. However, a great challenge in solid electrolyte batteries is forming a stable and ion conducting interface between the electrolyte and active material. This study investigates and characterizes a possible solid‐state electrode‐electrolyte pair for the high voltage active cathode material LiMn1.5Ni0.5O4 (LMNO) and electrolyte Li1+xAlxGe2‐x(PO4)3 (LAGP). In situ X‐ray diffraction measurements were taken on pressed pellets comprised of a blend of LMNO and LAGP during exposure to elevated temperatures to determine the product materials that form at the interface of LMNO and LAGP and the temperatures at which they form. In particular, above 600°C a material consistent with LiMnPO4 was formed. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy were used to image the morphology and elemental compositions of product materials at the interface, and electrochemical characterization was performed on LMNO‐coated LAGP electrolyte pellet half cells. Although the voltage of Li/LAGP/LMNO assembled batteries was promising, thick interfacial phases resulted in high electrochemical resistance, demonstrating the need for further understanding and control over material processing in the LAGP/LMNO system to reduce interfacial resistance and improve electrochemical performance. 相似文献
In the last years, the ionic liquid system formed by specific mixtures of 1‐ethyl‐3‐methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (EMIM[Tf2N]) and AlCl3 proved to be a very suitable electrolyte for the electrodeposition of aluminum. In order to establish an industrial electrodeposition process based on this novel electrolyte system, the suitability of melt crystallization for purification and recycling of these electrolytes has been studied. It exists a composition range in the ternary system where the compound EMIM[AlCl4] can be crystallized in a high purity. The layer melt crystallization technique is successfully applied to the binary system EMIMCl‐AlCl3 and to the real ternary electrolytes. Hydrolysis is proposed for treatment of the residue. In aqueous solutions, the membrane process nanofiltration is applied for concentration and recovery of the ionic components. An integral recycling concept is presented. 相似文献
Two types of micro‐tubular hollow fiber SOFCs (MT‐HF‐SOFCs) were prepared using phase inversion and sintering; electrolyte‐supported, based on highly asymmetric Ce0.9Gd0.1O1.95(CGO) HFs and anode‐supported based on co‐extruded NiO‐CGO(CGO)/CGO HFs. Electroless plating was used to deposit Ni onto the inner surfaces of the electrolyte‐supported MT‐HF‐SOFCs to form Ni‐CGO anodes. LSCF‐CGO cathodes were deposited on the outer surface of both these MT‐HF‐SOFCs before their electrochemical performances were compared at similar operating conditions. The performance of the anode‐supported MT‐HF‐SOFCs which delivered ca. 480 mW cm–2 at 600 °C was superior to the electrolyte‐supported MT‐HF‐SOFCs which delivered ca. six times lower power. The contribution of ohmic and electrode polarization losses of both FCs was investigated using electrochemical impedance spectroscopy. The electrolyte‐supported MT‐HF‐SOFCs had significantly higher ohmic and electrode polarization ASR values; this has been attributed to the thicker electrolyte and the difficulties associated with forming quality anodes inside the small (<1 mm) lumen of the electrolyte tubes. Further development on co‐extruded anode‐supported MT‐HF‐SOFCs led to the fabrication of a thinner electrolyte layer and improved electrode microstructures which delivered a world leading 2,400 mW cm–2. The newly made cell was investigated at different H2 flow rates and the effect of fuel utilization on current densities was analyzed. 相似文献
Summary: Highly porous poly[(vinylidene fluoride)‐co‐hexafluoropropylene] (PVdF‐HFP)/TiO2 membranes were prepared by a phase inversion technique, using dimethyl acetamide (DMAc) as a solvent and water as a non‐solvent. Their physical and electrochemical properties were then characterized in terms of thermal and crystalline behavior, as well as ionic conductivity after absorbing an electrolyte solution of 1 M LiPF6 dissolved in an equal weight mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC). For comparison, cast films and their electrolytes were also made by a conventional casting method without using the water non‐solvent. In contrast to the case of using N‐methyl‐2‐pyrrolidone (NMP) as a solvent, the PVdF‐HFP/TiO2 composite electrolytes, obtained using DMAc, exhibited superior properties of electrochemical stability and interfacial resistance with a lithium electrode but had lower ionic conductivities. It was also demonstrated that the phase inversion membrane was more effective than the cast film as the polymer electrolyte of a lithium rechargeable battery. As a result, a phase inversion membrane with 50 wt.‐% TiO2 was demonstrated to be the optimal choice for application in a lithium rechargeable battery.
Time evolutions of interfacial resistance between polymer electrolyte and lithium electrodes. 相似文献
The objective of this effort is to synthesize and characterize a series of lanthanum‐(La) doped Sr2MgMoO6 (SMMO) and La‐doped Sr2MgNbO6 (SMNO) anode materials which can be used in combination with lanthanum‐containing electrolytes to mitigate the effects of lanthanum poisoning in solid oxide fuel cells (SOFCs). Currently, an La0.4Ce0.6O1.8 (LDC) buffer layer is used with many perovskite‐based anode materials to prevent La diffusion into the anode from the La0.8Sr0.2Ga0.8Mg0.2O2.8 (LSGM) electrolyte which can create a resistive La species that impedes electrochemical performance. The LDC buffer layer, with diminished electronic conductivity, adds an extra level of complexity in the SOFC manufacturing process. Further, this extraneous layer presents an added experimental challenge when assessing anode material performance. Overall electrochemical performance could be improved if the resistive buffer layer could be removed, thereby allowing the anode material to have direct contact with the electrolyte. To accomplish this, a new class of anode materials was synthesized with the goal of balancing “La” chemical potential between these neighboring materials. La‐doped SMMO and SMNO were prepared and studied. It was hypothesized that by incorporating La into the anode, the gradient of chemical activity between the anode and electrolyte would decrease, which would prevent La diffusion. These anode materials were synthesized via a sol–gel methodology and characterized with X‐ray diffraction to assess phase purity. The conductivity of the materials was analyzed in the presence of both H2 and 100 ppm H2S/H2 to determine the stability and performance of these materials during device operation. The stability experiments demonstrated that 40% La‐doped SMNO is stable in all pertinent environments while not reacting with the LSGM electrolyte. 相似文献
In this paper we report the results of physical–chemical and electrochemical investigations performed on ternary mixtures of the room temperature ionic liquid (IL) N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI), propylene carbonate (PC), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as electrolyte for lithium-ion batteries. The thermal stability, ionic conductivity, viscosity and electrochemical stability windows of all considered mixtures were investigated and compared with those of electrolytes based on the pure PYR14TFSI and PC. The mixtures were also used as electrolyte in combination with LiFePO4-based electrodes. The specific capacity and cycling stability of these systems were investigated at different C-rates, both at room temperature and 60 °C. 相似文献