Printed by Eindhoven University Press, 2010. — 234 p.Table of contents
Introduction
Experimental and Theory
Lithium barrier layers for integrated microbatteries
Silicon thin film electrodes
Silicon 3D-nanostructured electrodes
Germanium thin film electrodes
Tin nitride film electrodes
Summary
Resume
Samenvatting
List of publications
Acknowledgements
Curriculum Vitae
Electronic portable devices are becoming more and more important in our daily life.
Examples of wide-spread electronic portable equipments are mobile phones, laptop
computers and digital cameras. In order to power these devices, on board electricity is
required. Electricity can effectively be provided either by capacitors or batteries. For
capacitors, electrons are simply stored at the electrode/dielectric interfaces, which results in
rather low volumetric energy densities. In batteries, however, electrons are stored inside the
electrode materials in a chemical manner, which results in a drastic increase of the
volumetric energy densities. Many portable types of electronic equipment rely on
rechargeable lithium-ion batteries as they can reversibly deliver the highest gravimetric and
volumetric energy densities [1]. The functioning principle of a lithium-ion battery is simple:
lithium-ions stored in the electrode materials are exchanged via the electrolyte while
electrons are transported through an external circuit to provide electrical energy to an
external load.
Lithium-ion batteries are currently rapidly expanding into very large-scale applications,
such as hybrid (electrical) cars, making transportation much more efficient. Miniaturized
autonomous devices, at the other end of the ‘spectrum’, are also becoming increasingly
important [2]. Characteristic for small autonomous devices is that they have to operate
independently. When devices are becoming smaller and smaller it becomes, however, much
more complicated to assemble batteries from their individual components. In addition, the
contribution of inactive overhead mass and volume by, for example, the package will
increase significantly. As the energy consumption for autonomous devices will be relatively
small this opens up the possibility to integrate (micro)batteries directly onto electronic
chips. Moreover, as certain applications have stringent safety requirements, for instance
medical implants, integrated batteries ideally should not contain any hazardous liquids which
might induce dangerous leakage issues.
