Lithium ion batteries (LIB) capture about 70% of the portable electronics market. The continued miniaturization of smart electronic devices calls for small batteries which can still provide large enough energy and power. In many devices the battery already takes up most of the available space. The issue is even more imperative for microsystems where battery power is needed for its autonomous operations sometimes in tandem with an energy harvestor. Whereas the ion conductivity of inorganic solid electrolyte materials such as LiPON is not suitable for large size batteries, it provides small enough cell resistance when used in sub-micrometer thin films. This concept allows direct integration with microsystems such sensors or implants. For these micro-batteries, microfabrication processes are (re)used. Ideas for innovation in micro-battery technology can also come from the IC industry, where the downscaling of the transistor has driven tremendous research efforts into new materials and the understanding of charge transport and interfaces.
We are looking for PhD students with backgrounds in chemistry, physics, materials science, electronic engineering and equivalent to join the research efforts of the energy storage team at imec in the development of all-solid-state thin-film micro-batteries. So far, our group has successfully demonstrated an increase in areal capacity of the thin-film electrodes by use of micro-structured substrates such as silicon micropillar arrays and nanowire scaffolds. The bottleneck for demonstration of functional full devices still remains in the thin-film electrolyte component and control of the interfaces over these large effective surface areas. The PhD work involves the development of deposition processes, the integration of the stack in a functional device and the characterization of the individual components as well as the obtained cells. The state-of-the-art nanofabrication facilities of imec and a fully equiped battery lab are at the disposal for the researcher. Eventually, these concepts will be evaluated for fabrication of flexible Li-ion battery cells. For this, cost effective alternatives for materials (e.g. nanowire arrays) and processing (e.g. (electro)chemical deposition) are being explored.
Required background: chemistry, physics, materials, electronic engineering or equivalent background with interest in electrochemistry, ionics and solid-state physics
Type of work: mostly experimental with optionally simulation of devices and stacks
Supervisor: Philippe Vereecken
Daily advisor: Maarten Mees
The reference code for this PhD position is SE1804-05. Mention this reference code on your application form.