“…There is also a category called ''Hardware'' related to the material aspect like batteries (Alkaline, Lithium-ion, Ni-Cd, Ni-Mh, ...), supercapacitors (activated carbon, Manganese (Mn), Graphite, ruthenium oxide (RuO2), selected electrolyte, ...), dielectric materials, etc... In this category, we also find the new technologies of ambient energy recovery [4], [5], [6], [7], hence the appearance of another generation of Wireless Sensor Networks with Energy Recovery (WSN-ER). These new technologies have attracted academia and industry attention because they provide sufficient confidence in the operability of the network since, the ability to collect ambient energy allows a sustainable operation of the sensor nodes and therefore, of the network as well.…”