Electrochemical Energy Storage and Conversion Devices

Detailed information about batteries and supercapacitors can be found in specialized textbooks [1-5]. Some useful concepts are reviewed below. 

Electrochemical storage systems (ESS) like batteries are generally assembled with more than one cell. Except special cases, identical cells connected in series or in parallel are used, most preferably with the same state of charge and the same state of performance reliability. 

The topic of this book is focused on active masses containing carbon, either as an active mass (e.g., negative mass of lithium-ion battery or electrical double layer capacitors), as an electronically conducting additive, or as an electronically conductive support for catalysts. In some cases, carbon can also be used as a current collector (e.g., Leclanche cell). This chapter presents the basic electrochemical characterization methods, as applicable to carbon-based active materials used in energy storage and laboratory scale devices. 

In the following we adopt the usual distinction between devices that convert chemical in electrical energy but cannot be electrically charged again (primary batteries), metabolistic cells in which active masses are continually supphed and removed by gas flow (fuel cells) and cells that can be recharged electrically (secondary batteries). In aU these cases great technological advances have been made and there exists a rich literature on these topics. 

There is a considerable interest in such systemsespecially since they represent a means of locally supplying electrical energy, necessary for, e.g., household appliances, telephones, clocks, laptops, or electrical vehicles. 

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Chapter 1 by Joachim Maier continues the solid state electrochemistry discussion that he began in Volume 39 of the Modem Aspects of Electrochemistry. He begins by introducing the reader to the major electrochemical parameters needed for the treatment of electrochemical cells. In section 2 he discusses various sensors electrochemical (composition), bulk conductivity, surface conductivity, galvanic. He also discusses electrochemical energy storage and conversion devices such as fuel cells. 

Solid State Electrochemistry, including the major electrochemical parameters needed for die treatment of electrochemical cells as well as the discussion of electrochemical energy storage and conversion devices such as fuel cells... 

Han, S., Wu, D., Li, S., Zhang, E, Feng, X., 2014c. Porous graphene materials for advanced electrochemical energy storage and conversion devices. Adv. Mater. 26,849-864. 

It is well known that for optimal performance of electrochemical energy storage and conversion devices, it is necessary to have a nonplanar electrode to increase reaction area. One requires a porous electrode with multiple phases that can transport the reactant and products in the electrode while also undergoing reaction [1] an analogy in heterogeneous catalysis is reaction through a catalyst particle [2], For traditional devices, porous electrodes are often comprised of an electrolyte (which can be solid or liquid) that carries the ions or ionic current and a solid phase that carries the electrons or electronic current. In addition, there may be other phases such as a gas phase (e.g., fuel cells). Schematically one can consider the porous electrode as a transmission-line model as shown in Fig. 1. 

In studies of solid materials like active masses in electrochemical energy storage and conversion devices knowledge of structural changes is of growing importance. Application of X-ray diffraction methods in particular under in situ conditions will thus increase. 

Ragone plots for electrochemical energy storage and conversion devices including batteries, fuel cells, and supercapacitors along with conversional capacitors. (Source Winter, M. 2004. 

Conventional electrochemical energy storage and conversion devices are typically two-dimensional (2-D), a parallel arrangement of planar cathode and anode separated by an electrolyte. In this design, the improvement of energy density is often at the ex-... 

In recent years, much intensive efforts have been made to produce graphene hybrid materials as electrodes for innovative electrochemical energy storage and conversion devices. A sequence of such materials was developed by hybridizing graphene with... 

There is an extended special literature3,10-16 on applications of solid state electrochemistry and even more on electrochemical devices. According to our objective, in this section applications will be emphasized in which migration and diffusion in the solid state are decisive processes (as discussed in Part I2). We intend to subsume such applications under the headlines composition sensors, composition actors, and energy storage or conversion devices. 

Debra R. Rolison is head of Advanced Electrochemical Materials at the Naval Research Laboratory (NRL). She received a B.S. in chemistry from Florida Atlantic University in 1975 and a Ph.D. in chemistry from the University of North Carolina at Chapel Hill in 1980 under the direction of Royce W. Murray. Dr. Rolison joined the Naval Research Laboratory as a research chemist in 1980. Her research at NRL focuses on the influence of nanoscale domains on electron- and charge-transfer reactions, with special emphasis on the surface and materials science of aerogels, electrocatalysts, and zeolites. Her program creates new nano structured materials and composites for catalytic chemistries, energy storage and conversion (fuel cells, supercapacitors, batteries, thermoelectric devices), and sensors. 

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