RETRACTED ARTICLE: Polymer electrolytes: characteristics and peculiarities

Polymer electrolytes are an important component of many electrochemical devices. This paper reviews state-of-the-art of the electrochemical and physical properties of polymer electrolytes. This review mainly encompasses the properties of different salts, solvents, and polymer hosts, which are encaged in liquid electrolytes. The additions of filler in polymer electrolytes result in composite polymer electrolytes, having high mechanical integrity and ionic conductivity, that are ideal electrolyte for these applications. The next generation state-of-the-art room-temperature ionic liquids based electrolytes, which are far superior to corresponding nonionic solvent-based electrolytes, are also discussed. An erratum to this article can be found at     

Polymer electrolyte for photoelectrochemical cell and dye-sensitized solar cell: a brief review

This paper reviews the use of solid polymeric electrolyte (SPE) and gel polymeric electrolyte (GPE) in photoelectrochemical cell (PEC) and dye-sensitized solar cell (DSSC). The structure of PEC and its working principle are presented. The various types of polymer electrolytes utilized in PEC and DSSC have been highlighted in this review. It also highlights the comparison of performance of PEC and DSSC utilizing those polymer electrolytes. This review is completed with the list of other SPEs that potentially be tested in DSSC.     

Recent advances on thermoelectric materials

By converting waste heat into electricity through the thermoelectric power of solids without producing greenhouse gas emissions, thermoelectric generators could be an important part of the solution to today’s energy challenge. There has been a resurgence in the search for new materials for advanced thermoelectric energy conversion applications. In this paper, we will review recent efforts on improving thermoelectric efficiency. Particularly, several novel proof-of-principle approaches such as phonon disorder in phonon-glass-electron crystals, low dimensionality in nanostructured materials and charge-spin-orbital degeneracy in strongly correlated systems on thermoelectric performance will be discussed.      

Photovoltaic cells technology: principles and recent developments

Solar energy is one of the renewable energy resources that can be changed to the electrical energy with photovoltaic cells. This article accomplishes a comprehensive review on the emersion, underlying principles, types and performance improvements of these cells. Although there are some different categorizations about the solar cells, but in general, all of them can be divided to crystalline silicon solar cells, thin film technology, III–V multijunction cells, dye-sensitized solar cells, polymer solar cells and quantum structured solar cells. Thin film technology is investigated in two non-crystalline silicon solar cells and chalcogenide cells. We present a complete categorization of solar cells and discuss the recent developments of different types of solar cells. Indeed, this paper covers almost all of the development processes of solar cells from their emersion in 1939 up to now. Also, due to substantial effects of the light trapping techniques on the improvements of the solar cells, a comprehensive study has been carried out.     

Quantum memories

We perform a review of various approaches to the implementation of quantum memories, with an emphasis on activities within the quantum memory sub-project of the EU integrated project “Qubit Applications”. We begin with a brief overview over different applications for quantum memories and different types of quantum memories. We discuss the most important criteria for assessing quantum memory performance and the most important physical requirements. Then we review the different approaches represented in “Qubit Applications” in some detail. They include solid-state atomic ensembles, NV centers, quantum dots, single atoms, atomic gases and optical phonons in diamond. We compare the different approaches using the discussed criteria.     

核电池概述及展望

核电池具有能量密度高、工作稳定可靠、无需人工干预等优点,在需要长期稳定供电的场合具有独特优势,其中热转换式核电池(RTG)是技术最为成熟且应用最早的一类,而β辐射伏特效应核电池已有商业化案例。目前,在β辐射伏特效应核电池研究中存在着放射源自吸收效应浪费能量、转化效率低、换能器件辐射损伤严重等问题,而对于一个实际的核电池,由于放射源自身不断衰变的属性,导致源的成分及其活度随着时间而发生变化,最终影响核电池的电学性能,其影响程度需要加以深入研究。本文以时间轴的形式对核电池的发展进行了全面回顾,简要介绍多种主流类型核电池的原理和应用范围;对于β辐射伏特效应核电池,指出放射源的自吸收是其中的关键科学问题。对于使用63Ni和TiT₂放射源的核电池,给出了其电学性能随时间变化的规律;指出对于某一特定结构的β辐射伏特效应核电池设计,在前期的模拟优化环节中,精细计算是至关重要的;最后提出了将放射源与换能材料相结合、使用含有较重同位素的换能器件的设想,这些设想有利于解决放射源自吸收问题、提高核电池输出功率和减轻辐射损伤的影响。     

Ionics—a key technology for our energy and environmental needs on the rise

Ionics is a key technology for storing, converting and using energy efficiently as well as protecting the environment. Major progress has been achieved in recent years in the understanding and development of individual materials components needed for ionic devices. It should be emphasized that only combinations of materials are eventually important and at least four interfaces exist with electronic and ionic junctions. The electrical fields exist over distances in the atomic range. Examples are given of recent successful developments of practically useful solids for lithium and oxide ion conduction in combination with appropriate electrodes. In addition, recent approaches to the design of ionic devices are described, notably the SEA concept for generating voltages in fuel cells and the coloration of single phase electrochromic materials. In order to overcome the tremendous problems in developing wide spread commercial applications, it is necessary to intensify our efforts in fundamental materials research drastically.     

The use of explosion in fabrication of new materials

Abstract

The energy of high explosives have been widely used for some time in improving characteristics of the existing materials as well as for creating new materials having good prospects for different technological applications. The two last decades witnessed especially remarkable results in this field. In this paper we shall give a concise review of explosive metal hardening and welding processes, explosive compaction of metalxnon-metal materials as well as of the equipment used in industrial applications of these and some other processes of explosive treatment of materials.     

Polymer electrolytes for lithium ion batteries: a critical study

Polymer electrolytes (PEs) are an essential component being used in most energy storage/conversion devices. The present review article on a brief history, advantage, and their brief application of polymer electrolyte systems. It consists of a glimpse on liquid, gel, and solid polymer electrolyte and a contrast comparison concerning benefits/disadvantages among the three. The article started with a brief introduction of polymer electrolytes followed by their varieties and extreme uses. The role of host polymer matrix by taking numerous examples of polymer electrolyte published by the different renowned group of the concerned field has been explored. The criteria for selection of appropriate host polymer, salt, inorganic filler/clay, and aprotic solvents to be used in polymer electrolyte have been discussed in detail. The mostly used polymer, salt, solvents, and inorganic filler/clay list has been prepared in order to keep the data bank at one place for new researchers. This article comprises different methodologies for the preparation of polymer electrolyte films. The different self-proposed mechanisms (like VTF, WLF, free volume theory, dispersed/intercalated mechanisms, etc.) have been discussed in order to explain the lithium ion conduction in polymer electrolyte systems. A numerous characterization techniques and their resulting analysis have been summarized from the different published reports at one place for better awareness of the scientific community/reader of the area.     

用于全固态锂电池的有机-无机复合电解质

固态电解质被认为是解决传统液态锂金属电池安全隐患和循环性能的关键材料,但仍然存在离子电导率低,界面兼容性差等问题.设计兼顾力学性能、离子电导率和电化学窗口的有机-无机复合型固态电解质材料是发展全固态锂电池的明智选择.近年来,基于无机填料与聚合物电解质的有机-无机复合电解质备受关注.设计与优化复合电解质结构对提高复合电解质综合性能具有重要意义.本文详细梳理了有机-无机复合固态电解质在全固态锂电池中展现的多方面优势,从满足不同性能需求的复合电解质结构设计角度出发,综述了有机-无机复合电解质在锂离子传导、锂枝晶的抑制、界面稳定性和相容性等方面的研究进展,并对有机-无机复合电解质的未来发展趋势和方向进行了展望.     

PEO electrolytes containing dioctyl phthalate (DOP) for dye-sensitized nanocrystalline TiO2 solar cells

In this paper, we aim to prepare polymer electrolytes consisting of NaI and I₂ dissolved in poly(ethylene oxide) (PEO) and dioctyl phthalate (DOP) as an additive and apply the electrolytes to dye-sensitized solar cells (DSSC). Upon the incorporation of salt, the phthalic-stretching C=O bands of DOP in Fourier transform infrared spectra shifted to a lower wave number (Δf = 93 cm⁻¹), confirming the unusual strong complex formation between sodium ions and phthalic oxygen. Coordinative interactions and structural changes of PEO/NaI/I₂/DOP electrolytes have also been characterized by wide angle X-ray scattering, presenting an almost amorphous structure of the polymer electrolytes. The ionic conductivity of the polymer electrolytes reached ∼10^–4 S/cm at room temperature at the mole ratio of [EO]:[Na]:[DOP] = 10:1:0.5, as determined by the four-probe method. DSSC using the polymer electrolytes and conductive indium tin oxide glasses exhibited 2.9% of overall energy conversion efficiency (=P _max/P _in × 100) at one sun condition (100 mW/cm²). The good interfacial contact between the electrolytes and the dye-attached nanocrystalline TiO₂ layers were verified by field-emission scanning electron microscopy.     

A Review of Monte Carlo Simulations of Polymers with PERM

In this review, we describe applications of the pruned-enriched Rosenbluth method (PERM), a sequential Monte Carlo algorithm with resampling, to various problems in polymer physics. PERM produces samples according to any given prescribed weight distribution, by growing configurations step by step with controlled bias, and correcting “bad” configurations by “population control”. The latter is implemented, in contrast to other population based algorithms like e.g. genetic algorithms, by depth-first recursion which avoids storing all members of the population at the same time in computer memory. The problems we discuss all concern single polymers (with one exception), but under various conditions: Homopolymers in good solvents and at the Θ point, semi-stiff polymers, polymers in confining geometries, stretched polymers undergoing a forced globule-linear transition, star polymers, bottle brushes, lattice animals as a model for randomly branched polymers, DNA melting, and finally—as the only system at low temperatures, lattice heteropolymers as simple models for protein folding. PERM is for some of these problems the method of choice, but it can also fail. We discuss how to recognize when a result is reliable, and we discuss also some types of bias that can be crucial in guiding the growth into the right directions.     

Advanced lithium ion battery materials

Although a commercial reality, the lithium ion battery is still the object of intense R&D aimed to further improve its performance. In this paper we review the activities in progress in our laboratory for the characterization of novel, not-carbonaceous anode materials, high-voltage cathode materials and composite polymer electrolytes.     

Cruising in ceramics—discovering new structures for all-solid-state batteries—fundamentals,materials, and performances

Energy storage research has drawn much attention recently due to increasing demand for carbon neutral electrical energy from renewable energy sources such as solar, wind, and hydrothermal. Various electrochemical energy storage and conversion technologies are being considered for their integration into smart grid systems, of which batteries seem to play a vital role due to their wide range of energy densities. In this review, we provide the current status and recent advances in solid-state (ceramic) electrolytes based on inorganic compounds for all-solid-state batteries. This paper is specifically focused on the fundamentals, materials, and performances of solid electrolytes in batteries. A wide spectrum of inorganic solid-state electrolytes is presented in terms of their chemical composition, crystal structure, and ion conduction mechanism. Furthermore, the advantages and main issues associated with different types of inorganic solid electrolytes, including β-alumina, NASICON and LISICON-type, perovskites, and garnet-type for all-solid-state batteries are presented. Among these solid electrolytes, Zr and Ta-based Li-stuffed garnets exhibit high Li-ion conductivity, electrochemical stability window (up to 6  V/Li at room temperature), and chemical stability against reaction with molten elemental Li. However, their stability under humidity and carbon dioxide should be improved to decrease the fabrication and operational costs.     

Polymers with spatial or topological constraints: Theoretical and computational results

In this review, we provide an organized summary of the theoretical and computational results that are available for polymers subject to spatial or topological constraints. Because of the interdisciplinary character of the topic, we provide an accessible, non-specialist introduction to the main topological concepts, polymer models, and theoretical/computational methods used to investigate dense and entangled polymer systems. The main body of our review deals with (i) the effect that spatial confinement has on the equilibrium topological entanglement of one or more polymer chains and (ii) the metric and entropic properties of polymer chains with fixed topological states. These problems have important technological applications and implications for life sciences. Both aspects, especially the latter, are amply covered. A number of selected open problems are finally highlighted.     

Effect of tetrabutylammonium iodide content on PVDF-PMMA polymer blend electrolytes for dye-sensitized solar cells

The influence of tetrabutylammonium iodide on the polyvinylidene fluoride-poly(methyl methacrylate)-ethylene carbonate (PVDF-PMMA-EC)-I₂ polymer blend electrolytes was investigated and optimized for use in a dye-sensitized solar cell. The different weight ratios (50, 60, 70, and 80 %) of tetrabutylammonium iodide (TBAI)-added PVDF-PMMA-EC-I₂ polymer electrolytes were prepared. The prepared solid polymer blend electrolytes were characterized by using various techniques such as Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), and electrochemical impedance spectroscopy (EIS). The FT-IR spectra revealed the interaction among all composition of polymer electrolytes. The influence of TBAI salt on the ionic conductivity of polymer electrolytes was studied using electrochemical impedance spectroscopy. The polymer electrolyte containing 60 % of TBAI in PVDF-PMMA-EC-I₂ showed the highest room temperature conductivity of 5.10?×?10^?3 S cm^?1. The fabricated DSSC using PVDF-PMMA-EC-I₂ polymer electrolytes with 60 % of TBAI showed the best performance with a short-circuit current density of 8.0 mA cm^?2, open-circuit voltage of 0.66 V, fill factor of 0.65, and the overall power conversion efficiency of 3.45 % under an illumination of 100 mW cm^?2. Hence, the weight content of organic iodide salt in polymer electrolytes influences the overall performance of dye-sensitized solar cells.     

Impedance spectroscopy of PEO-lithium triflate confined in nanopores of alumina membranes

Polymeric electrolytes are very useful for their technological applications in different electrochemical devices such as batteries, electrochromic devices, smart windows, etc. One of the most studied solid electrolyte system is PEO (poly-ethylene oxide) complexed with various lithium salts. A limitation of this polymer electrolyte is low ionic conductivity. However, nanoscale manipulation of the solid polymer electrolyte has the potential to address this issue. This work discusses how it is possible to increase the PEO conductivity when this polymer is contained in nanostructures, specifically nanopores. The nanostructures used are alumina filtration membranes (thickness=6 μm, diameter=13 mm) with three different pore sizes 0.02 μm, 0.1 μm and 0.2 μm. Electrochemical characterization has been performed with an HP4194A Impedance/Gain phase analyser and Solartron 1260 Impedance/Gain phase analyser. The former instrument tests these films at a high frequency (from 100 Hz to 40 MHz) while the later at low frequency (from 1 Hz to 1 MHz). From these experiments, it has been determined that two regions of ion conduction exit. One is conduction through the bulk polymer electrolyte in the pores while the other is an interfacial conduction at the interface between the pore walls and the PEO electrolyte. The conductivity of the PEO is increased when confined in these nanostructures. Invited Scholar Research from: LiCryl — INFM (Liquid Crystal Regional Laboratory) c/o Department of Physics, University of Calabria, Via P. Bucci Cubo 31C, I-87036 Rende (CS) Italy Paper presented at the Patras Conference on Solid State Ionics - Transport Properties, Patras, Greece, Sept. 14 – 18, 2004.     

Conductivity study of some polymer electrolytes based on polyacrylonitrile

The present paper deals with the room temperature conductivity study of some polymer electrolytes based on polyacrylonitrile, ammonium tetraflouroborate as dopant, and propylene carbonate (PC) and polyethylene glycols (PEG300 and PEG600) as plasticizers. The additions of plasticizers having different dielectric constant have been found to modify the conductivity of polymer electrolytes. The increase in room temperature conductivity with plasticizer addition has been found to depend upon (1) the amount of salt present and (2) amount of plasticizers added. The polymer electrolytes prepared were characterized by X-ray diffraction, scanning electron micrographs, infrared, thermogravimetric, and AC impedance measurements. The highest room temperature conductivity observed in case of these polymer electrolytes was ∼10–13 s/cm.     

Preparation and characterization of blend polymer electrolyte film based on poly(vinyl alcohol)-poly(acrylonitrile)/MgCl<Subscript>2</Subscript> for energy storage devices

The development of magnesium electrolytes for battery applications has been the demand for electrochemical devices. To meet such demand, in this work solid blend polymer electrolytes were prepared using polyvinyl alcohol (PVA) and polyacrylonitrile (PAN) (92.5PVA:7.5PAN) as host polymer, magnesium chloride (MgCl₂) of different molar mass percentage (m.m.%) (0.1, 0.2, 0.3, 0.4, 0.5, and 0.6%) as salt and dimethylformamide (DMF) as solvent. Structural, vibrational, thermal, electrical, and electrochemical properties of the prepared electrolytes were investigated using different techniques such as X-ray diffraction pattern, FTIR spectroscopy analysis, differential scanning calorimetry (DSC), AC impedance measurement, and transference number measurement. X-ray diffraction studies confirm the minimum volume fraction of crystalline phase for the polymer electrolyte with 0.5 m.m.% of MgCl₂. FTIR confirms the complex formation between host polymer and salt. DSC analysis proves the thermal transition of the prepared films are affected by salt concentration. The optimized material with 0.5 m.m.% of MgCl₂ offers a maximum electrical conductivity of 1.01 × 10^?3 S cm^?1 at room temperature. The Mg²⁺ ion conduction in the blend polymer electrolyte is confirmed from transference number measurement. Electrochemical analysis demonstrates the promising characteristic of these polymer films suitable as electrolytes for primary magnesium batteries. Output potential and discharge characteristics have been analyzed for primary magnesium battery which is constructed using optimized conducting electrolyte.     

Synchronization in complex networks

Synchronization processes in populations of locally interacting elements are the focus of intense research in physical, biological, chemical, technological and social systems. The many efforts devoted to understanding synchronization phenomena in natural systems now take advantage of the recent theory of complex networks. In this review, we report the advances in the comprehension of synchronization phenomena when oscillating elements are constrained to interact in a complex network topology. We also take an overview of the new emergent features coming out from the interplay between the structure and the function of the underlying patterns of connections. Extensive numerical work as well as analytical approaches to the problem are presented. Finally, we review several applications of synchronization in complex networks to different disciplines: biological systems and neuroscience, engineering and computer science, and economy and social sciences.