The proliferation of low-power and ultralow-power electronics has enabled a rapid growth of autonomous devices that ranges from consumer electronics and nomad devices to autonomous sensors and sensor networks used in industrial and military environments. Hence, a wide range of application domains has been impacted by such technologies (aeronautic, civil engineering,biomedical engineering, home automation, etc.). Although batteries have initially promoted the spreading of these autonomous devices thanks to their relatively high energy capacity, they have become a break in the development of such systems especially when dealing with “left-behind” (or “place and forget”) sensors or when these apparatus are deployed.
