2. State of the art of electrical energy storage microdevices

2.1 Microbatteries

Microbatteries are devices whose architecture can be simplified to a stack of two electrodes separated by a micrometrically-thick solid-state electrolyte. The important elements are almost similar to those of larger-scale lithium-ion batteries, in particular the positive current collector, cathode, electrolyte, anode and negative current collector (figure 2 ). In general, all microfabrication processes are carried out in a cleanroom. The device is built on a silicon, glass or metal substrate, and the various layers are deposited under ultra-high vacuum. The resulting devices have thicknesses of several tens of microns and surface areas of between 1 and 100 mm ^2...