Crystalline chlorinated contorted hexabenzocoronene: a universal organic anode for advanced alkali-ion batteries

Abstract

Alkali-ion batteries such as Li-ion batteries (LIBs), Na-ion batteries (NIBs), and K-ion batteries (KIBs) have attracted significant attention because of their fascinating energy storage characteristics. However, the development of universal anode materials for LIBs, NIBs, and KIBs remains challenging owing to the different ionic radii of alkali ions. Here, we demonstrate chlorinated contorted hexabenzocoronene (Cl-cHBC), a small organic molecule, as a novel universal anode material for LIBs, NIBs, and KIBs. The nonplanar cHBC molecule with judiciously selected chlorine substituents not only increased the interlayer spacing but also induced capacitive properties through interaction between chlorine and alkali ions for NIBs and KIBs. Furthermore, significantly improved rate performance was observed for intercalation-dominant LIBs, which exhibited an excellent specific capacity of 220 mA h g⁻¹ at a high current density of 8 A g⁻¹ without significant changes over 1000 cycles. In addition, owing to the pseudocapacitive behavior of the Cl-cHBC anode, satisfactory cycling performance was achieved for NIBs and KIBs, with reversible specific capacities of approximately 175 and 260 mA h g⁻¹, respectively. Thus, this work demonstrates Cl-cHBC as a promising universal organic anode and presents a viable design strategy for developing anode materials for LIBs, NIBs, and KIBs based on small organic molecules.