The diatomite-templated carbons were prepared using diatomite as template and furfuryl alcohol as carbon resource, and were further activated using potassium hydroxide as an activating agent. The structure, pore parameters, and electrochemical capacity of diatomite-templated carbons after activation were investigated to evaluate the influence of activated condition. The results showed active carbons contained a proportion of disordered materials in the form of amorphous carbon and ordering decreased at higher activation temperatures, however, it had little relationship to KOH/carbon mass ratio. Pore parameters, such as the specific surface area and pore volume, as well as the micropore volume, showed a growing trend with the increase of activation temperature and KOH/carbon mass ratio but micro porosity showed an opposite trend. The specific capacitance of all samples were ranging from 51.5 to 98.1 F g−1 at current density of 1 A g−1 and capacitance retention could maintain at more than 70% at current density of 20 A g−1, indicating they had good electrochemical properties. Moreover, electrochemical property became better as activation temperature and KOH/carbon mass ratio decreased.
Titanium was prepared from TiCl4 in molten NaCl-KCl-NaF salt. The product of the reaction of TiCl4 with NaF was identified using X-ray diffraction, and its electrochemical behavior was studied using cyclic voltammetry and square wave voltammetry. The electrochemical deposition of titanium was investigated during the addition of TiCl4 to NaCl-KCl-NaF melts. The results indicate that Na2TiF6 was first obtained through the reaction of NaF with TiCl4 in the NaF-KCl-NaCl melt, and Na2TiF6 was decomposed to Na+ and [TiF6]2− in the melts. [TiF6]2− was then sequentially reduced to [TiF6]3− and Ti at the cathode, accompanied by chlorine gas emission at the anode and fluoride formation at the cathode.
Degradation of lithium-ion battery (LIB) was evaluated by using liquid chromatography-quadruple time of flight mass spectroscopy (LC-QToF/MS). Lab-made LIBs were degraded by storing at their states of charge of 50% at 25 or 60°C for three months. The degradation of the LIB was accelerated at 60°C compared with that at 25°C. The electrochemical impedance spectroscopy analysis suggested that the remarkable degradation occurred for solid electrolyte interphase (SEI): it was implied that on one hand, the composition of the SEI for the LIB degraded at 25°C did not vary, on the other hand, that at 60°C varied. For LC-QToF/MS analysis, although decomposed products derived from the electrolyte solution were detected from the electrolyte in the LIB degraded at both 25 and 60°C, those decomposed products were almost the same. Whereas, the difference between decomposed products at 25 and 60°C was confirmed for the interphases between electrodes and electrolyte. The characteristic decomposed products at 60°C was a product with more than C35 and more than 500 m/z of mass number. This product should be one of the reason of capacity degradation due to the internal resistance increase. Thus, a possibility of LC-QToF/MS was demonstrated.
This study was aimed at the preparation of an electrode for alkali water electrolysis, which had excellent catalytic activity by use of electroplating of alloys made of abundant metal, such as Fe and Ni. The hydrogen overvoltage of the Fe-Ni-W alloy plated electrode was the smallest through the measurement, moreover the hydrogen overvoltage was reduced after a long electrolysis. The elemental composition and the enlargement of the surface area were confirmed by SEM and EDX analysis. Involvement of Fe and W of Fe-Ni-W alloy plated electrode will be one factor for its high catalytic activity. Thus plated Fe-Ni-W alloy electrodes were compared with the Fe alloy plated electrodes considering of their water electrolysis performance. The catalytic activity of Fe-Ni-W plated electrode showed the best performance comparing to Fe-W-P or Fe-Ni alloy plated electrodes as both anode and cathode. Also comparing to the stainless steel which had been widely used in the field of industrial water electrolysis, the Fe-based alloy plated electrode showed better performance as the electrodes for water electrolysis.