347 research outputs found
Nanostructured Alloys and Advanced Configuration Lithium Ion Batteries
No full textThe objective of this thesis work is to switch from standard to renewed configuration lithium ion battery by replacing the conventional graphite anodes with new generation of lithium alloying electrodes characterized by high capacity, by long cycle life and by enhanced safety characteristic. Conventional lithium alloying electrodes are considered in chapter II. They are synthesized and characterized as the starting materials, to evidence their potentialities, i.e. the high specific capacity and the high safety level. In addition, problems and drawbacks associated with these materials, i.e. high mechanical stress during the electrochemical process and poor cycle life, are evidenced. Standard protocols, such as synthesis procedures, morphological and structural analysis, in addition to electrochemical testing condition are proposed. The conclusions of this chapter give us the preferential direction of the subsequent chapters. Nanostructured alloys, characterized by revolutionary structure, enhanced performances in terms of specific capacity and cycle life, and high safety level are described and characterised in chapter III. Various nanostructured composite materials, i.e. Ni3Sn4, SnCoC, Sn-C, Sb-C and SnSb-C are reported. Different synthetic routes, i.e. electrodeposition, high energy ball milling and gelification are discussed in view of the preparation of the materials, differing by chemical structure. Common properties of these materials are the particle size of the order of tents of nanometers, and particular architectures, characterized by free space which contains the volume variation associated with the lithium alloying process. Finally, in chapter IV, the new family of nanostructured electrodes to be employed as the negative electrode in advanced, new design lithium ion batteries using different kind of cathodes, such as lithium iron phosphate, LiFePO4, layered lithium nickel cobalt manganese oxide, LiNi0.33Co0.33Mn0.33O2 and high voltage lithium nickel manganese spinel, LiNi0.5Mn1.5O4, are reported. Considering the determining role of the safety, in addition to conventional liquid electrolyte lithium ion batteries, new systems, involving safe, highly conductive electrolytes, i.e. gel based and ionic liquids, are assembled and characterized. The experimental data demonstrate that these new lithium ion batteries are safe, with high performances in terms of energy, power, cycle life and rate capability, and candidate it as a valid alternative to the conventional energy storage systems
Functional Materials for Energy Applications. Lithium batteries: current technologies and future trends
No full textLithium batteries: current technologies and future trends
B Scrosati and J Hassoun, Sapienza University of Rome, Italy
Functional materials represent a class of advanced energy conversion materials, including photoelectric, thermoelectric, electrochemical, piezoelectric and electromagnetic materials. These materials are already widely used in renewable energy applications, such as photovoltaics (PV), hydrogen production and storage and fuel cell systems, as well as in demand-side systems such as lighting, energy recovery and energy storage. Global demands for lower cost, higher efficiency, mass-production and, of course, sustainably sourced systems, coupled with discoveries and innovation in underlying nanotechnology, have led applications based on functional materials to become an increasingly important and promising part of the sustainably energy mix.
This book presents a comprehensive review of the issues, science and development of functional materials in core renewable energy production and sustainable energy management applications. The book initially deals with solar power materials, reviewing the development and sustainability of advanced PV devices, with particular focus on thin-film technologies. The next two sections cover materials development for hydrogen production and storage, and for fuel cells, providing the reader with a critical understanding of the issues facing the integration of these systems into the current energy infrastructure, as well as their potential implementation in a hydrogen-based economy. The final section covers demand-side technologies, reviewing ways in which function materials apply to reducing the energy demand within the built environment, along with energy storage applications that are an essential part of a sustainable energy mix with increasing penetration of renewable energy sources. An appendix focussing on materials simulation approaches rounds off the book’s coverage
Advanced lithium-ion, lithium sulfur, lithium-air and new generation rechargeable batteries and energy storage systems
No full text
RECHARGEABLE ELECTROCHEMICAL METAL ION CELL AND ACCUMULATOR CONTAINING SAID CELL
No full textA rechargeable electrochemical metal ion cell comprising: - a negative electrode (anode) (1 ); - a positive electrode (cathode) (2); - an electrolyte system (3) interposed between said negative electrode and said positive electrode, wherein: - said negative electrode (1) comprises at least one metal capable of releasing and accepting metal ions; - said positive electrode (2) comprises at least one compound capable of releasing and accepting metal ions different from those of the negative electrode (1); - said electrolyte system (3) comprises: - a glycol-based electrolyte solution containing a salt of a metal included in the negative electrode (1 ) and a salt of a metal included in the positive electrode (2); - a matrix of solid and/or polymer and/or gel type adapted to retain said electrolyte solution, where two reversible reactions take place simultaneously in said cell: a reversible deposition and dissolution process of ions of a metal included in the negative electrode (1 ) takes place in said negative electrode and a reversible ion exchange process of a metal included in the positive electrode (2) takes place in said positive electrode and said metals are different from one another
Application of Graphene-Based Electrodes in Lithium-Ion Battery
No full textThe recent widespread of electric (EVs) and hybrid vehicles (HEVs), with the final goal of reducing the greenhouse gas emission and atmosphere pollution, required efficient and clean power sources. Due to their high energy density, lithium-ion batteries are an ideal candidate as side system to store energy from renewable sources and power electric vehicles1. Although appropriate for the consumer electronic market, the present lithium-ion battery technology is still inadequate for the electric motion. The large diffusion of LIBs is still prevented by issues, including poor safety, high cost, restrict operating temperature range and materials availability. Improvements in energy density and safety, as well as reduction in cost, are mandatory steps to meet the EVs and HEVs severe targets2. Among the issues of LIBs technology, low theoretical capacity of the graphite anode, i.e. 372 mAh g-1, represents a limiting parameter. Indeed, great attention is now focusing on the study of alternative anode material such as Sn (994 mAh g-1), Si (4200 mAh g-1) or SnO2 (782 mAh g-1), however their application is still limited by the large volume changes upon lithium alloying-de-alloying processes. Recently, the suitability of the graphene as negative electrode in replacement of the commercial graphite anode has been demonstrated. Graphene-based electrodes have the possibility to accommodate increased amount of Li-ions in respect to common graphite3, thus allowing a capacity value two to three times higher in respect to graphite. Herein, we report the use of different types of graphene-based electrodes in lithium-ion cell
A low-cost, high-energy polymer lithium-sulfur cell using a composite electrode and polyethylene oxide (PEO) electrolyte
No full textHerein, we report a polymer cell using high-energy lithium metal anode, a composite sulfur-carbon cathode, and polyethylene oxide (PEO)-lithium trifluoromethan sulfonate (LiCF3SO3) electrolyte. The limited cost of raw materials as well as the very simple synthetic procedures, involving planetary ball milling (for S-C cathode) and solvent casting (for PEO-electrolyte), are expected to reflect into remarkable reduction of the economic impact of the proposed battery. Furthermore, the high energy of the Li-S cell and safety of
the polymer configuration represent additional bonuses of the system. The S-C material, revealing a maximum capacity as high as 700 mAh g−1 in liquid electrolyte, is employed in a lithium-sulfur battery with the polymer configuration. The polymer cell delivers a capacity of 450 mAh g−1 at a voltage of about 2 V; hence, a theoretical energy density of 900 Wh kg−1 that may reflect into a high practical value, suitable for energy storage applications
Accumulatori litio-zolfo ad alta energia
No full textli accumulatori litio-ione sono leggeri, compatti, con un voltaggio nell’ordine dei 3-4 V e con densità di energia compresa tra 150-250 Wh Kg-1, per questa ragione queste batterie, più di altre quali le nickel metallo idruro (NiMH), le nickel cadmio (NiCd) e le batterie piombo acido, trovano impiego nel mercato dell’elettronica di consumo. Tuttavia l’evoluzione di quest’ultimo, con la produzione di nuovi dispositivi che richiedono livelli di potenza sempre più elevati e lo sviluppo di nuovi sistemi quali quelli ad autotrazione elettrica con autonomia fino a 500 km, rende le batterie al litio attualmente in commercio inadeguate di fronte alle aspettative di mercato. Un miglioramento delle loro prestazioni in termini di densità di energia nonché un abbassamento dei costi legati alla loro realizzazione risulta dunque necessario. Tale incremento può realizzarsi attraverso lo studio di materiali alternativi a quelli attualmente utilizzati quali catodi a base di LiCoO2 o LiMn2O4 e anodi di grafite.Gli accumulatori litio-zolfo stanno suscitando molto interesse poiché lo zolfo oltre ad essere caratterizzato da un’elevata energia specifica (circa 2500 Wh Kg-1) è anche un elemento molto abbondante in natura, poco costoso ed ecocompatibile. Ciò nonostante la diffusione su larga scala di questi accumulatori risulta limitata da problematiche legate allo zolfo quali la sua bassa conducibilità elettrica, l’espansione volumetrica durante la conversione in Li2S e l’elevata solubilità dei polisolfuri di litio nell’elettrolita organico
CELLA ELETTROCHIMICA RICARICABILE IBRIDA AGLI IONI METALLICI ED ACCUMULATORE CONTENENTE TALE CELLA
No full textHigh capacity tin-iron oxide-carbon nanostructured anode for advanced lithium ion battery
No full textA novel nanostructured SneFe2O3eC anode material, prepared by high-energy ball milling, is here originally presented. The anode benefits from a unique morphology consisting in Fe2O3 and Sn active nanoparticles embedded in a conductive buffer carbon matrix of micrometric size. Furthermore, the Sn metal particles, revealed as amorphous according to X-ray diffraction measurement, show a size lower than 10 nm by transmission electron microscopy. The optimal combination of nano-scale active materials and micrometric electrode configuration of the SneFe2O3eC anode reflects into remarkable electrochemical performances in lithium cell, with specific capacity content higher than 900 mAh g1 at 1C rate (810 mA g1 ) and coulombic efficiency approaching 100% for 100 cycles. The anode, based on a combination of lithium conversion, alloying and intercalation reactions, exhibits exceptional rate-capability, stably delivering more than 400 mAh g1 at the very high current density of 4 A g1. In order to fully confirm the suitability of the developed SneFe2O3eC material as anode for lithium ion battery, the electrode is preliminarily studied in combination with a high voltage LiNi0.5Mn1.5O4 cathode in a full cell stably and efficiently operating with a 3.7 V working voltage and a capacity exceeding 100 mAh g1
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