In the world of energy storage, supercapacitors and batteries constitute the most obvious example that you cannot have it all. Or can you? High-power-density SCs are handicapped by low energy densities whereas the best among batteries, LIBs feature the best energy densities but lag behind in power. Yet, they both are in the midst of intense developments given the expansion of energy storage markets. These complementary drawbacks hamper the applications of SCs and LIBs when both high energy and high power densities are essential. Thus, the race is on to develop new energy storage materials and systems which could deliver high energy at high rates. And, of course, at low cost.
On the other hand, the complementarity of SCs and batteries allows for a positive view of the question by considering the development of hybrid devices, electrodes or materials which could combine the faradaic processes of batteries with the capacitive mechanism of SCs in a synergic combination. Lithium (or potassium) Ion Capacitors (LICs or KICs) are precisely that; hybrid arrangement of a battery-like electrode (as anode) and SC-like electrode (as cathode) in organic electrolyte, heading to enhanced energy and power densities [10]. Moreover, LICs don’t suffer the substantial volume changes and phase transitions of battery electrodes, thus featuring excellent cycle life, comparable to that of SCs. We explore various device configurations such as
- Asymmetric Supercapacitors (ASC)-Aqueous system
- Hybrid Supercapacitors (HSC)-Aqueous system
- Lithium/Potassium Ion Capacitor (LIC or KIC)-Non-aqueous system
- Non-flammable and safe electrolytes
