4 - The role of nanomaterials for supercapacitors and hybrid devices

Abstract

Nanosizing strongly influences the performances of electrical double-layer capacitors (EDLCs), pseudocapacitors, and hybrid supercapacitors. The charge storage behaviors of carbonaceous active materials employed in EDLCs are especially affected by the size and morphology. Decrease of the size can be realized at particle and electrode level through porous structures engineering by tailoring the morphology and size of the carbon active materials. Pseudocapacitive active materials are also affected by size. Indeed, a faradaic material exhibiting an EDLC electrochemical signature independent from the particle size can be described as “intrinsic” pseudocapacitive. Interestingly, materials with battery-type features (i.e., presenting reversible redox activity) can also become pseudocapacitive by nanosizing. Hybridization at the device level of capacitive and faradaic-type electrodes also offers the possibility of simultaneous delivery of high energy and high power. Finally, nanosizing can improve the charge storage transport in the electrode, thus, enhancing the electrical conductivity and reaction kinetics. In this chapter, all these aspects are thoroughly discussed and reviewed.