The synthesis, properties and applications of polypyrrole (PPy), a representative of conducting polymers, are reviewed. Chemical and electrochemical methods for the preparation of PPy and PPy films and the effect of the reaction conditions on the properties of the polymer produced are discussed. The mechanisms of electrochemical polymerisation of pyrrole are compared. The physicomechanical properties of the polymer, its morphology and structure are discussed. The mechanism of charge transfer in PPy is considered within the framework of the model of quasi-equilibrium concentrations of polarons and bipolarons. The methods for modification of the electrochemical performance of PPy are reviewed, in particular, synthesis of PPy from pyrrole derivatives with the appropriate electroactive groups and introduction in the PPy of electroactive dopant anions and the effect of those on the electrochemical performance of PPy films are considered. Examples of the use of PPy are given and the prospects for its application in various areas are discussed. The bibliography includes 254 references.

https://iopscience.iop.org/article/10.1070/RC1997v066n05ABEH000261/pdf

Polypyrrole : a conducting polymer; its synthesis, properties and applications

The development of advanced rechargeable batteries for efficient energy storage finds one of its keys in the lithium-ion concept. The optimization of the Li-ion technology urgently needs improvement for the active material of the negative electrode, and many recent papers in the field support this tendency. Moreover, the diversity in the chemical nature of the materials studied so far requires a systematization work to be done to envisage the main guidelines for research and future progress areas. This review starts with an analysis of the major advantages and drawbacks of the lithium metal electrode that led to the development of the Li-ion concept. The successful carbon-based materials, including numerous forms of both natural and anthropogenic origins are then mentioned. Attention is paid to the materials prepared from side products of the petroleum industry. Then, the central part of the report concerns alternative possibilities that have emerged from the use of tin, antimony and other elements that reversibly form alloys and compounds with lithium. The systematic study takes into account the chemical nature of the elements directly involved in the reversible reactions with lithium. Thus, tin and other group 14 elements, pnictides, and oxides are summarized in three consecutive sections. In the first section, particular attention will be paid to tin oxides and phosphates and the “SnSb” compounds serves as a link with the next section. Among the metal pnictides, compounds such as CoSb 3 and CrSb 2 , are described as precursors of the electroactive material in a dispersing matrix. Also phosphides, such as CoP 3 and MnP 4 , are also discussed, the latter having interesting intercalation reactions with lithium. Finally, the recently revised field of using transition metal oxides that allow a reversible Li 2 O formation on cycling is discussed. In each section, several materials evaluated in our laboratory are included.

Inorganic materials for the negative electrode of lithium-ion batteries: state-of-the-art and future prospects

LAYERED molybdenum and tungsten dichalcogenides have stimulated considerable interest as lubricants1,2, battery cathodes3–5, and catalysts6–8. Pure, crystalline group VI transition-metal dichalcogenides are normally prepared by intermittently grinding and heating the elements at >900 °C for several days. Low-temperature solution routes to these materials have also been explored9–11. In those studies, exchange (metathesis) reactions between transition-metal halides and alkali-metal sulphides or covalent sulphiding agents in polar organic solvents were found generally to yield finely divided products at close to ambient conditions. Here, in contrast, we consider the factors that influence reactions between transition-metal halides and alkali-metal chalcogenides in the solid state. These highly energetic reactions, driven by the formation of very stable product species, provide a powerful method for the rapid synthesis of materials normally prepared at high temperatures over long periods of time. Other advantages of these solid-state reactions include control of reaction conditions and of product particle sizes. Although our study focuses on group VI transition-metal dichalcogenides, analogous metathesis reactions can be used for rapid syntheses, initiated at low temperatures, of many other technologically important materials.

Rapid solid-state synthesis of materials from molybdenum disulphide to refractories

A synthesis methodology is demonstrated to produce MoS2 nanoparticles with an expanded atomic lamellar structure that are ideal for Faradaic-based capacitive charge storage. While much of the work on MoS2 focuses on the high capacity conversion reaction, that process is prone to poor reversibility. The pseudocapacitive intercalation-based charge storage reaction of MoS2 is investigated, which is extremely fast and highly reversible. A major challenge in the field of pseudocapacitive-based energy storage is the development of thick electrodes from nanostructured materials that can sustain the fast inherent kinetics of the active nanocrystalline material. Here a composite electrode comprised of a poly(acrylic acid) binder, carbon fibers, and carbon black additives is utilized. These electrodes deliver a specific capacity of 90 mAh g−1 in less than 20 s and can be cycled 3000 times while retaining over 80% of the original capacity. Quantitative kinetic analysis indicates that over 80% of the charge storage in these MoS2 nanocrystals is pseudocapacitive. Asymmetric full cell devices utilizing a MoS2 nanocrystal-based electrode and an activated carbon electrode achieve a maximum power density of 5.3 kW kg−1 (with 6 Wh kg−1 energy density) and a maximum energy density of 37 Wh kg−1 (with 74 W kg−1power density).

Pseudocapacitive Charge Storage in Thick Composite MoS 2 Nanocrystal-Based Electrodes

Studies on new chemically deposited photoconducting antimony trisulphide thin films

Amorphous Molybdenum Sulfide Electrodes for Nonaqueous Electrochemical Cells

Une couche mince de MoS 3 sur un substrat d'aluminium, nickel, silice ou alumine est preparee par depot chimique en phase vapeur, dans un domaine de temperature de 150 a 400 o C, a partir d'hexafluorure de molybdene et d'hexamethyldisilthiane en solution non aqueuse. Ce film est caracterise par spectroscopie IR a transformee de Fourier, par des mesures de resistivites et d'epaisseur

Y. L. Barberio

Papers

Amorphous Molybdenum Sulfide Electrodes for Nonaqueous Electrochemical Cells

MoS3 Thin Film Cathodes Prepared by Chemical Vapor Deposition

Amorphous Molybdenum Sulfide Electrodes for Nonaqueous Electrochemical Cells.

MoS3 Thin Film Cathodes Prepared by Chemical Vapor Deposition