Supercapacitors vs. batteries: similarities and differences

Although both supercapacitors and batteries are used for electrochemical energy storage, their performances differ with respect to some important parameters, e.g., their specific energy and specific power densities. While these differences are well-known and can be readily explained based on the different charge storage mechanisms (i.e., double layer charging versus redox reactions), the reasons for the similarities observed between the performances of supercapacitors and e.g., 3D-microbatteries are rarely discussed. It is also well-known that the same materials (e.g., metal oxides or electronically conducting polymers) can be used both in supercapacitors and batteries. Given that supercapacitors and batteries are considered to represent two different types of electrochemical storage devices, it is not always immediately clear why a material behaves differently in a supercapacitor and a battery. This presentation aims at explaining the similarities and differences between supercapacitors and batteries using examples involving cellulose-based energy storage devices and nanostructured electrode materials for lithium-based batteries.

Author bio: Leif Nyholm, who holds a position as full professor at the Department of Chemistry-Ångström Laboratory at Uppsala University, Sweden, obtained his Ph.D. in Analytical Chemistry in 1989 and worked as a post-doc at Southampton University, UK, between 1990 and 1992. His current work includes research on lithium-based batteries e.g., diffusion-controlled lithium trapping effects, 2D nucleation and growth of lithium on lithium-metal electrodes, and electrodeposition of nanostructured electrodes, as well as paper-based electrochemical energy storage devices, functional cellulose-based separators, and corrosion resistant high entropy alloys.