The hydrous ruthenium oxide has been formed by a sol‐gel process. precursor was obtained mixing aqueous solutions of and alkalis. powder annealing the at low temperatures. crystalline structure electrochemical properties have studied as function temperature. At lower temperatures is in an amorphous phase with high specific capacitance. Specific capacitance 720 F/g measured for 150°C. When temperature exceeded 175°C, formed, dropped rapidly. surface area resistivity pellet made from these...

The hydrous form of ruthenium oxide has been demonstrated to be an excellent electrode material for electrochemical capacitors. This material, as prepared by a sol‐gel process at low temperatures, is amorphous and electrically conductive. specific capacitance over . value least two times higher than the highest ever reported such materials. charge storage mechanism believed involve bulk protonation oxide. discovery opens new avenue research in field high energy density

A new lithium salt based on a chelated borate anion, BOB [bis(oxalato)borate] is evaluated as the electrolyte solute for lithium-ion cells by both electrochemical means and cell testing. Controlled potential coulometry study reveals that anion can stabilize aluminum substrate to more positive potentials than popular hexafluorophosphate does, while slow scan cyclic voltammograms show good compatibility of with graphitizable carbonaceous anode well satisfactory stability against charged...

The formation chemistry of graphite/electrolyte interface and its dependence on electrolyte bulk composition were investigated by conducting electrochemical impedance analyses interfaces systematically formed in various electrolytes NMR identification surface species harvested therefrom. interpretation these strongly suggests that Li+ solvation sheath structure is central defining the anode chemistry, because solvent molecules preferentially recruited into would be reduced graphene upon...

Understanding the factors limiting Li+ charge transfer kinetics in Li-ion batteries is essential improving rate performance, especially at lower temperatures. The process involved lithium intercalation of graphite anode includes step de-solvation solvated liquid electrolyte and transport preformed solid interphase (SEI) on electrodes until accepts an electron electrode becomes a Li electrode. Whether or through SEI depends nature interphases interfaces. Several examples involving materials...

The oxidative stability and initial oxidation-induced decomposition reactions of common electrolyte solvents for batteries electrical double layer capacitors were investigated using quantum chemistry (QC) calculations. electrolytes consisted linear (DMC, EMC) cyclic carbonate (EC, PC, VC), sulfone (TMS), sulfonate, alkyl phosphate paired with BF4–, PF6–, bis(fluorosulfonyl)imide (FSI–), difluoro-(oxalato)borate (DFOB–), dicyanotriazolate (DCTA–), B(CN)4– anions. Most QC calculations...

Although biaxially-oriented polypropylene thin film is a common dielectric for many high voltage pulsed power capacitor applications, the electrical conductivity under field at elevated temperature mostly unknown. Such knowledge valuable not only better understanding of origin and transport mechanisms charge species field, but also gaining insight improving breakdown strength electro-thermal modeling energy density, capacitors. In this work, conduction mechanism was investigated...

Using ac impedance, we studied the formation process of solid electrolyte interface (SEI) film on graphite electrode during initial cycles. Results show that SEI takes place through two major stages. The first stage at voltages above 0.25 V (before lithiation graphite), which a loose and highly resistive is formed. second occurs narrow voltage range 0.25-0.04 V, proceeds simultaneously with electrode. In stage, stable, compact, conductive produced. © 2001 Electrochemical Society. All rights reserved.

Using alkyl phosphates and a cyclophosphazene as cosolvents, the possibility of formulating nonflammable electrolyte for lithium-ion batteries was explored. The emphasis placed on determining impact these flame-retarding additives performance electrolyte. It found that although cosolvents at high contents effectively suppress flammability electrolyte, their effectiveness is still insufficient to render electrolytes completely nonflammable. Furthermore, such reduction in always realized...

We scrutinized the conventional practice of measuring an electrolyte stability window. It is shown that misleading values might be generated by this practice. Thus, we recommend to obtain a real window, working electrode material should simulate electrodes used in device. Further, applications have high‐surface‐area electrode, new quantification window proposed. The electrochemical various nonaqueous electrolytes are derived way reflect actual operation limits these real‐life devices. © 1999...

The electrical conductivity of cuprous chloride containing a dispersion fine alumina particles was studied as function volume fraction (0–0.212) and particle size (0.3 0.06 μm initial size). At low temperatures the ionic may be increased by much two orders magnitude. enhanced conductivity, Δσ, proportional to surface area added alumina. Both these data earlier Liang (1) were fitted relation, where is radius dispersoids fraction.

Electrochemical capacitors can be divided into two types depending on whether the salt concentration in electrolyte changes during charging and discharging. In first type of capacitor, such as double‐layer capacitors, reduces capacitor. The maximum energy density this capacitor will depend not only specific capacitance operating voltage, but also electrolyte. paper, a formula describing dependence capacitance, is given based optimized weight (or volume) ratio electrode material It shows that...

Lithium ethylene dicarbonate ((CH2OCO2Li)2) was chemically synthesized and its Fourier transform infrared (FTIR) spectrum obtained compared with that of surface films formed on Ni after cyclic voltammetry (CV) in 1.2 M lithium hexafluorophosphate (LiPF6)/ethylene carbonate (EC):ethyl methyl (EMC) (3:7, w/w) electrolyte metallic cleaved in-situ the same electrolyte. By comparison IR experimental spectra compound, we established title compound is predominant species both instances. Detailed...

Capacitors are a good example of the fact that even simplest device can become complicated given 250 years evolution.

In this work we demonstrate that the fluorination of alkyl substituents on phosphate can reduce viscosity, enhance flame-retarding efficiency, and increase electrochemical stability cosolvents. Therefore new flame retardant be used at a concentration greater than 20% in electrolyte, as cosolvent, order to formulate completely nonflammable electrolyte works lithium-ion cells. This formulation not only increases safety feature battery, while maintaining capacity utilization rate capability,...

A homologous series of lithium alkyl mono- and dicarbonate salts was synthesized as model reference compounds for the frequently proposed components constituting electrolyte/electrode interface in Li-ion batteries. The physicochemical characterization these bulk state using thermal analyses X-ray photoelectron, nuclear magnetic resonance, Fourier transform infrared spectroscopies establishes a reliable database comparison studies on surface chemistry electrodes harvested from cells.