Vol 54, No 4 (2018)

Nanocomposite polymer electrolytes represent a perspective class of polymer electrolytes for electrochemical devices in which nanodisperse filler is introduced to the “solvating matrix + lithium salt” base composition. This three-section paper reviews studies devoted to the preparing and investigating of different types of novel nanocomposite polymer electrolytes for lithium power sources carried out for the last 15 years. Its first section is devoted to the solid nanocomposite polymer electrolyte consisting of polyethylene oxide, lithium salt, and nanodisperse filler (Al₂O₃, TiO₂, SiO₂, etc.); the second section, to nanocomposite polymer membranes based on the polyvinylidene fluoride-co-hexafluoropropylene that can be used as a substitute for inert polyolefine separator of polypropylene, polyethylene, or their alternating layers. It is this type of the nanocomposite polymer electrolytes that is the most perspective one; the great majority of publications are dedicated to this electrolyte. The third section of the review covers the studies of the nanocomposite polymer electrolytes based on different polymers, oligomers, and co-polymers prepared by different methods. Nanoparticles of Al₂O₃, TiO₂, SiO₂, ZnO, MgO, Fe₃O₄, Ca₃(PO₄)2, ZrO₂, clay, ferroelectric ceramics SrBi₄Ti₄O₁₅, a compound SO₄^2-–ZrO₂, molecular sieves, nanochitin, etc., are discussed as possible additives to the nanocomposite polymer electrolytes. The reference list contains 101 items.

The electrodeposition of zinc–nickel alloys (5–16 at % Ni) from the ammonium oxalate electrolytes is studied. It is shown that the ratio between the alloy components has an effect on the corrosion resistance of the coatings, their structure, chemical and phase composition, and microhardness.

Full computer simulation of the cathode structure in hydrogen–oxygen fuel cell with polymer electrolyte is performed. Both transport, support grains (agglomerates of carbon particles onto whose surface Pt-catalyst is deposited), and the current generation in active layer are simulated. The active layer operation in potentiostatic mode is studied. The effect of variations of the active layer and the fuel cell temperature (T_s and Т, respectively) on the cathode overall current I and the support grain flooding with water is calculated. The changes in the temperature difference T_s–Т was shown for the first time, experimentally and by the simulation, to generate variations of I and the degree of the support grain flooding with water. In particular, with the increasing of T_s–Т the current I increased, whereas the support grain flooding with water decreased; and vice versa, with the decreasing of T_s–Т the current I drops down, while, the support grain flooding with water grows. An explanation of the phenomena is presented, which takes account of structure of the support grains in which О₂ reduction and Н₂О generation occur. There exist intrinsic channels for protons and О₂ molecules transportation to the catalyst. Water releasing in the support grains is able to fill partially or even entirely the gas pores through which oxygen is supplied to the platinum. As a result, the current generated in the support grains can drop down significantly; at the same time, the value of I also drops down. The degree of the support grainfilling with water is determined by two processes, namely, the flooding and draining. The source of flooding is the current generation; that of draining, the water saturated vapor diffusion and water filtration in nanopores. The lower cathode potential, the higher the flooding rate, whereas the water removal rate grows or drops down with the increasing of decreasing of the temperature difference Т_s–Т, respectively. Thus, the temperature difference variations naturally lead to those of the quantity I.

Lipophilic compounds combining oxy- and ester-groups are synthesized and studied as neutral ionophores in plasticized PVC membranes for the development of novel water hardness ion-selective electrodes. Electrodes based on the ionophores studied showed a higher selectivity to calcium over magnesium ions. However, for electrodes based on hexadecyl-4-hydroxybutanoate or decyloxybutanol this preference turned to be rather low: logK_CaMg=–(0.5–0.7). Electrodes with membranes containing hexadecyl-4- hydroxybutanoate, 0.3 M as a neutral ionophore and bis[4-(1,1,3,3-tetramethylbutyl)phenyl]phosphate, 0.01 M as a charged ionophore, in combination with Ca²⁺-selective electrode based on ETH 1001 as ionophore, proved to be suitable for measurements of water hardness, also for the measurement of Mg²⁺ ion content in artificial aquarium fish-breeding water samples and in samples modeling electrolyte composition of blood serum.