Situ Synthesis

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Background: Nanotechnology is an increasingly employed concept in the development and progression of a wide variety of technologies, including the field of electrochemistry. Nano-size materials have been investigated and discovered for use as anode materials in energy storage and conversion devices such as electrodes and capacitors. Currently, carbon is a preferred material for use in anodes, however, there are disadvantages associated with the use of carbon.  It is desirable to develop a process for synthesizing nano-particles including metals, such as Si, contained in a nano-structured matrix. It is believed that an active material in an inactive matrix can result in a large capacity as well as the desired reversibility enabling superior performance as compared to carbon as an anode material. Furthermore, it is believed that the presence of carbon nanotubes can contribute to improved performance. The compliant nature of carbon nanotubes and their ability to bend and flex can result in the nanotube maintaining electrical contact with the active material during alloying and de-alloying and thus, preserving the desirable high gravimetric capacity of the active material.   Technology: The current invention disclosure relates to the development of a novel in situ process for the generation of nanoscale composites of Si and C based hetero-structures exhibiting capacities of 1000 mAh/g and higher with excellent capacity retention. The disclosure contains two parts. First, to develop novel mechanochemical reduction approaches to generate in-situ nano-structured silicon. The improved high energy mechanochemical reduction approach will lead to uniform dispersion of the nano-sized Si in graphitic carbon.  Carbon nano-tubes derived using economical chemical vapor deposition (CVD) methods will also be incorporated to generate novel nano-scale composite hetero-structures that will likely exhibit capacities higher than 1000 mAh/g. A second aspect of the invention is to identify novel polymer binders that exhibit higher fracture strength and toughness compared to PVDF, the currently used binder. These novel binders will likely render higher stabilities to the electrodes during electrochemical cycling.   Application: * Generation of new anode materials