Литиевые электрохимические системы

The corrosion and electrochemical behavior of magnesium and the MA 21 magnesium-lithium alloys in solutions of moderately acidic phosphates with various additives was studied. The inhibiting effect of nitrate and fluoride ions on the anode dissolution of these objects was revealed. Features of the electrochemical dissolution of magnesium and the magnesium-lithium alloys in nitrate phosphate solutions with fluoride ions caused by their activation-passivation competition have been noted.

Possibilities for increasing efficiency of impedance spectral measurements are investigated. It is shown that for determination of linear electrochemical impedance a linearly changing input signal is preferable, and for the quantitative estimation of non-linearity of electrochemical impedance as an input signal it is expedient to use the cosine electric beats. The constructive diagrams of generators of such signals are offered.

In article experience of application of chemical sources of a current of electrochemical system lithium – tionilchloride and batteries on their basis, in onboard systems of electrosupply of modern and perspective space-rocket technics of Russia is presented.

It is shown that an examination of reduced galvanostatic charge-discharge curves allows making preliminary conclusion on degradation mechanism upon cycling. If such degradation is due to loss of active material all normalized curves coincide. In the case of insulating films building up normalized curves are shifted along potential axis. Various structure changes result in qualitative change of curves shape.

On basis of analysis of literature data as well as of own experimental results we suggest some regularity for degradation of silicon electrodes upon cycling. It was shown that an electrode capacity Q at n-th cycle can be calculated from equation Q = Q₀ exp(kn+?n²/2), where Q₀ is initial capacity value, k и ? are empiric constants.

This message was transferred with a trial version of CommuniGate(r) Pro* First pilot samples of composite sheetings based on various metallic matrixes (Al, Cr, Mn, Fe, Ni) and ceramic fillers ((Al₂O₃, Cr₂O₃, MnO₂, Fe₃O₄, NiO, AlN etc.) were obtained by means of the reverse galvanostatic technique.

It is has been shown that the generalized Peukert equation gives the best result when calculating the capacity given by sealed nickel-cadmium accumulators at different discharging currents.

The results of the design of a fully-tight Ni-MH battery of the NMG type are presented. The authors have developed a spread technique of making both negative and positive electrodes with sheet foam nickel as a conducting support. The influence of the density of both charging and discharging current and the discharge temperature on the discharging characteristics of the power source was studied.

Samples having the chemical formula Li_0.5 Fe_{2.5 – x} Mg_xO₄ (0 ? x ? 1) were prepared by the standard ceramic method. The parts of the dielectric constant ?', ?'' and A.C. conductivity ?(?) are measured at different frequencies from 10 ^{– 2} to 10⁵ Hz in the room temperature and different cooling velocity, and then the dielectric loss tangent tg ? was calculated. The sample with x = 0.1 what was cooled quickly showed the greatest values of ?₀ as compared with the other samples.

Electrochemical behavior of Li in the systems with PE based on polymers of chlorinated polyvinylchloride and polyvinylidene fluoride were investigated by the method of cyclic voltammetry and galvanostatic cycling. Potentiodynamic investigations have shown that on lithium electrode even in the systems with polymer electrolyte the high current densities up to 5 mA/cm² are realized. Influence of polymer electrolyte composition on the properties of the interface Li/electrolyte and rechargeable work of lithium electrode has been shown.