Vol 52, No 12 (2016)

The review summarizes the development of lithium ion batteries beginning with the research of the 1970–1980s which lead to modern intercalation type batteries. Following the history of lithium ion batteries, material developments are outlined with a look at cathode materials, electrolyte solutions and anode materials. Finally, with lithium sulfur and lithium oxygen batteries two post intercalation type lithium batteries are discussed. The focus of the material discussions lies on basic understanding, problems and opportunities related to the materials.

We report the use of nano-impacts as a novel method for the study of photochemical reactions of individual nanoparticles (NPs). The conversion of gelatine stabilised silver bromide (AgBr) NPs to silver (Ag) NPs through photochemical reduction by ascorbic acid is studied mechanistically. Two mechanisms are proposed and investigated by monitoring the amount of electrochemically accessible AgBr against the time scale of conversion, measured through the use of the nano-impacts technique.

The process of electroxidative polymerization of magnesium 5,15-di(n-methoxyphenyl)porphine MgP(MeOPh)₂ is studied. The presence of substituents in positions 5 and 15 of the porphine macroring makes reactive two of its four meso positions, which allows new bonds to be formed only in the opposite positions 10 and 20. As a result, the process of electropolymerization of this substituted monomer at its oxidation can produce only linear chains, in contrast to unsubstituted magnesium porphine MgP for which the polymer structure can both be linear and contain zigzag and/or cruciform fragments.

A potentially implantable biocathode with the function of charge accumulation based on a nanobiocomposite including multiwall carbon nanotubes, polyaniline, and bilirubin oxidase is developed. The regularities of the functioning of the obtained electrode are studied in air–saturated phosphate buffer solution, pH 7.4 (PB), and also in phosphate buffer solution containing redox–active blood components (BMB). The open circuit potential of the biocathode is 0.33 and 0.08 V vs. the saturated calomel electrode in PB and BMB, respectively; it is completely restored after at least three self-charge/discharge cycles with connection to resistors with different resistance. Bioelectrocatalytic current density of oxygen reduction is 0.50 and 0.42 mA cm^–2 with the residual activity of 78 and 60% of the initial value after 12 h of continuous operation in PB at 25°C and in BMB at 37°C, respectively.

The formalism of Kramers–Moyal expansion is used for a stochastic description of one-stage electrochemical discharge occurring via a single route. In the stochastic model under consideration, an electrochemical reaction is represented as two independent random series of anodic and cathodic elementary acts of charge transfer. Each of two random series obeys its generalized Poisson’s distribution. Three Kramers–Moyal expansions are determined. The first Kramers–Moyal expansion works near the equilibrium potential. It takes into consideration both (anodic and cathodic) series of elementary acts. The second expansion determines the stochastic behavior of electrochemical reaction at high anodic potentials. The third expansion controls the stochastic behavior of electrochemical reaction in the range of high cathodic overpotentials. The dependence of coefficients of the Kramers–Moyal expansion on the macroscopic parameters of electrochemical discharge is determined. In view of interdisciplinary character of the theory of noise and fluctuations, a stochastic description of electrochemical discharge within the framework of Kramers–Moyal expansion is of interest also for the general theory of stochastic processes.

The electrochemical polymerization of 3,4-ethylenedioxythiophene (EDOT) in the presence of the salt and acid forms of polymer sulfonates with different polymer-chain flexibility is studied. The dependence of the rate of synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) on the nature of polysulfonate counterion that determines the type and distribution density of the charge in the polyelectrolyte chain is demonstrated. For the Н⁺ form of a rigid-chain polysulfonate, it is found that the specific interactions between parts of its macromolecules lead to destabilization of EDOT•⁺ radical cations, hinder the growth of PEDOT chains, and favor the formation of structures with the high degree of charge localization.