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Otto Haas

Bio: Otto Haas is an academic researcher from Paul Scherrer Institute. The author has contributed to research in topics: Electrolyte & Electrode. The author has an hindex of 41, co-authored 83 publications receiving 6319 citations.


Papers
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TL;DR: The goal of the present article is to provide a survey of electroactive polymers in view of potential applications in rechargeable batteries, and reviews the preparative methods and the electrochemical performance of polymers as rechargeable battery electrodes.
Abstract: Electrochemical energy storage systems (batteries) have a tremendous role in technical applications In this review the authors examine the prospects of electroactive polymers in view of the properties required for such batteries Conducting organic polymers are considered here in the light of their rugged chemical environment: organic solvents, acids, and alkalis The goal of the present article is to provide, first of all in tabular form, a survey of electroactive polymers in view of potential applications in rechargeable batteries It reviews the preparative methods and the electrochemical performance of polymers as rechargeable battery electrodes The theoretical values of specific charge of the polymers are comparable to those of metal oxide electrodes, but are not as high as those of most of the metal electrodes normally used in batteries Therefore, it is an advantage in conventional battery designs to use the conducting polymer as a positive electrode material in combination with a negative electrode such as Li, Na, Mg, Zn, MeH{sub x}, etc 504 refs

1,481 citations

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TL;DR: In this article, the available results of research, both on rechargeable negative electrodes based either on metallic magnesium or alternative materials, and on materials suitable as positive, magnesium-inserting (counter)electrodes for secondary magnesium batteries, are critically reviewed.

339 citations

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TL;DR: In this article, pre-irradiation grafting of styrene/divinylbenzene mixtures into poly(fluoroethylene-co-hexafluoropropylene) films and subsequent sulfonation was used for fuel cell applications.

261 citations

Journal ArticleDOI
TL;DR: In this article, a solution-prepared pure lithium nickel oxide, LiNiO 2, was evaluated as a function of the calcination temperature and manganese content, with a specific charge of 170 mAh g -1 for materials with a Ni:Mn ratio of about 1:1
Abstract: Lithium nickel manganese oxides, LiNi 1-y Mn y O 2+δ , (0 ≤ y ≤ 05) were prepared via a new solution technique The corresponding mixed nickel manganese hydroxide precursors were synthesized in an oxidative coprecipitation method Subsequent calcination in the presence of LiOH leads to crystalline products with a partially disordered layered-type α-NaFeO 2 structure X-ray photoelectron spectroscopic analysis has indicated a strong enrichment of lithium at the surface The electrochemical performance of these materials as positive electrodes in lithium-ion batteries was evaluated as a function of the calcination temperature and manganese content A calcination temperature of 700°C leads to the best cycling stability At this temperature, a sufficiently high degree of crystallinity was achieved, having a strong influence on the cycling stability of these 4 V materials The specific charge and cycling stability obtained for the solution-prepared pure lithium nickel oxide, LiNiO 2 , was low, but was significantly enhanced by replacing some nickel with manganese With increasing manganese content, the specific charge increased to about 170 mAh g -1 for materials with a Ni:Mn ratio of about 1:1 Ex situ magnetic susceptibility measurements proved that during lithium deinsertion, the trivalent manganese is preferentially oxidized, and seems to be the more reactive redox center in these oxides

208 citations

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TL;DR: In this paper, a detailed overview of metal oxides in relation to their behavior in batteries is presented, covering electrochemical, conductivity, ion diffusivity, spectroscopic, and other physico-chemical data.
Abstract: Due to their rather low molecular weight and their favorable electrochemical and solid‐state properties, first row transition metal oxides seem to be specially attractive as cathode materials in electrochemical energy storage systems. Therefore, we undertook a detailed overview, covering electrochemical, conductivity, ion diffusivity, spectroscopic, and other physico‐chemical data on metal oxides in relation to their behavior in batteries. Metal oxide‐based primary batteries have achieved a high technological level and yield energy densities of up to 300 Wh kg−1 or 880 Wh l−1. Oxide‐based secondary batteries, on the other hand, typically yield less than 100 Wh kg−1. Based on the present review, V, Cr, Mn, and Co oxides seem to be the most promising solid‐state cathode materials for future high performance secondary batteries.

182 citations


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06 Feb 2008-Nature
TL;DR: Researchers must find a sustainable way of providing the power their modern lifestyles demand to ensure the continued existence of clean energy sources.
Abstract: Researchers must find a sustainable way of providing the power our modern lifestyles demand.

15,980 citations

Journal ArticleDOI
TL;DR: This paper will describe lithium batteries in more detail, building an overall foundation for the papers that follow which describe specific components in some depth and usually with an emphasis on the materials behavior.
Abstract: In the previous paper Ralph Brodd and Martin Winter described the different kinds of batteries and fuel cells. In this paper I will describe lithium batteries in more detail, building an overall foundation for the papers that follow which describe specific components in some depth and usually with an emphasis on the materials behavior. The lithium battery industry is undergoing rapid expansion, now representing the largest segment of the portable battery industry and dominating the computer, cell phone, and camera power source industry. However, the present secondary batteries use expensive components, which are not in sufficient supply to allow the industry to grow at the same rate in the next decade. Moreover, the safety of the system is questionable for the large-scale batteries needed for hybrid electric vehicles (HEV). Another battery need is for a high-power system that can be used for power tools, where only the environmentally hazardous Ni/ Cd battery presently meets the requirements. A battery is a transducer that converts chemical energy into electrical energy and vice versa. It contains an anode, a cathode, and an electrolyte. The anode, in the case of a lithium battery, is the source of lithium ions. The cathode is the sink for the lithium ions and is chosen to optimize a number of parameters, discussed below. The electrolyte provides for the separation of ionic transport and electronic transport, and in a perfect battery the lithium ion transport number will be unity in the electrolyte. The cell potential is determined by the difference between the chemical potential of the lithium in the anode and cathode, ∆G ) -EF. As noted above, the lithium ions flow through the electrolyte whereas the electrons generated from the reaction, Li ) Li+ + e-, go through the external circuit to do work. Thus, the electrode system must allow for the flow of both lithium ions and electrons. That is, it must be both a good ionic conductor and an electronic conductor. As discussed below, many electrochemically active materials are not good electronic conductors, so it is necessary to add an electronically conductive material such as carbon * To whom correspondence should be addressed. Phone and fax: (607) 777-4623. E-mail: stanwhit@binghamton.edu. 4271 Chem. Rev. 2004, 104, 4271−4301

5,475 citations

Journal ArticleDOI
TL;DR: In this article, the fundamental principles, performance, characteristics, present and future applications of electrochemical capacitors are presented in this communication, and different applications demanding large ECs with high voltage and improved energy and power density are under discussion.

4,175 citations

Journal ArticleDOI
TL;DR: Supercapacitors are able to store and deliver energy at relatively high rates (beyond those accessible with batteries) because the mechanism of energy storage is simple charge-separation (as in conventional capacitors) as discussed by the authors.

3,620 citations