Щелочные аккумуляторы

The paper considers the most significant properties of moulding solutions based on a mixture of polyvinylidene fluoride and polystyrene for the process of capillary-free electrospinning nonwoven materials. It has been shown that the material obtained from the mixed solution of polyvinylidene fluoride and polystyrene in the ratio of components 0.75 : 0.25 is the largest porous, the diameter of the fibers is in the widest range from 0.14 to 2.8 ?m, and branching of the fibers is observed.

The current situation in technology and developments in the field of polymer binders for composite electrodes of lithium electrochemical systems are discussed. A wide range of synthetic and natural polymers used for this purpose is considered. Emphasis is placed on commercially available materials, which form aqueous solutions or dispersions. The advantages of multifunctional polymer binders are demonstrated.

The energetic properties of the new composite electrode materials suitable for electrochemical capacitors were investigated. Composite electrodes were made using Norit A activated carbon and synthesized sparingly soluble copper salts such as copper iodide(I) and hexacyanoferrates (II), etc. (III). The composition of the salts was confirmed by elemental analysis and the particle size was determined by the Scherrer equation using the data of X­-ray phase analysis.

This paper is the conclusion to the series of the articles devoted to the problem of accelerated charging of a lead-acid battery. In this paper we investigated the possibility of increasing the charge efficiency by applying the asymmetric current at the second stage. In addition, the effect of using admissible charging rates on the resource, the admissible number of consecutive cycles, and gas release were studied.

The paper presents the results of the study of phase composition and electrochemical performance of lithium-manganese oxide spinel with excess lithium of nominal composition of Li_{1 + x}Mn₂O₄ obtained by solid-phase method. It was established that samples with x = 0.1 and 0.2 were composite materials with LiMn₂O₄ being the basic phase and Li₂MnO₃ being the impurity (3 and 7 mas.%, respectively) also comprising trace amounts of MnO₂.

The influence of small amounts of the Fe, Co, and Ni impurities on the spontaneous hydrolytic process of borohydride was studied within a temperature range of 60–100°C. The object under study was a simulated solution containing 9.53 M of OH^- ions and 0.14 M of BH₄^- ions, used as a fuel for borohydride fuel cells. The rate constant k of borohydride hydrolysis for a small amount of impurities at different temperature was estimated. The lowest non-accelerating concentrations of the impurities were established ( ? 10 ppm for iron? ?

The structure and specific electrochemical characteristics of a mixed cathode material based on ground LiNi_1/3Mn_1/3Co_1/3O₂ (NMC111) and highly porous activated carbon YEC-8B were studied. The mixed material containing 35 wt. % NMC111 and 65 wt. % YEC-8B (based on the mass of active materials), has a specific capacity ?70% higher in comparison with the cathode material based on pure coal YEC-8B.

It was established that at the cathodic treatment of titanium in aqueous dimethyl sulfoxide solutions of sodium molybdate, containing phosphoric acid, at the potential of the cathodic incorporation of sodium (E_c  = ? 2.6 V) in the potentiostatic mode, the composition formed on the electrode surface layer depended not only on the composition of the solution, but also on the volume ratio of the aqueous electrolyte solution and the organic solvent (dimethyl sulfoxide).

The third part of the review is devoted to polymer binders with electronic conductivity used to make composite electrodes for lithium electrochemical systems. Polymer semiconductors (“synthetic metals”), related polymers with additionally introduced functional groups, related copolymers and mixtures of polymers, as well as carbon chain polymers and copolymers with inсorporated polyaromatic fragments are considered.

A method of deriving standard electrochemical impedance spectroscopy (EIS) data such as Bode diagram, Nyquist diagram, and others from frequency dependence of the external impedance using numerical differentiation of the indicated dependence in quadratic coordinates is proposed, the method being named as the differential electrochemical impedance spectroscopy (DEIS). The method was tested experimentally on polyvinyl alcohol-based proton membranes doped with sulphated montmorillonite in granulated or dispersed states as an example.