All-Organic Potassium Ion Hybrid Capacitor

A hybrid ion capacitor (HIC), which is a merger of the best properties of a battery and a supercapacitor, has been attracting much interest in recent times. Parallelly, sodium- and potassium-based devices are actively explored beyond lithium chemistry. In an attempt to develop organic material-based energy storage devices, we demonstrate the fabrication of an all-organic potassium ion hybrid capacitor (KIHC). The all-organic hybrid device employs dipotassium terephthalate (K2TP) as the anode and polyaniline (PANi) as the cathode. Along with the cyclic voltammetry method, we use the “three-dimensional Bode analysis” technique to study the charge storage mechanism in these electrodes. The full-cell device exhibits excellent electrochemical properties demonstrating a high energy density of 153 W h kg–1, a high power density of 6795 W kg–1, and good cycle stability up to 10,000 cycles. The results are promising for building all-organic energy storage devices with improved energy and power densities toward building a sustainable and ecofriendly energy storage economy.