The 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.
Nanostructured Alloys and Advanced Configuration Lithium Ion Batteries
HASSOUN, Jusef
2009
Abstract
The 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.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
