Small Molecule Azaacene as an Anode Material for Lithium-Ion Batteries

In recent years, organic electrodes have attracted much attention owing to their unique properties including low density, flexibility, and in certain cases ultra-high capacity. In this contribution, we report the synthesis of a novel small molecule azaacene (SmAz) and reveal its electrochemical performance as an anode material in Li-ion batteries. SmAz delivers a reversible capacity of around 550 mA h g(-1) at 50 mA g(-1), a value that exceeds its theoretical capacity (237 mA h g(-1)). Moreover, SmAz displays an activation process in which the capacity increases with cycle time. Operando XRD suggests SmAz becomes amorphous during cycling. Greater insight into the charge storage mechanism is revealed with impedance and cyclic voltammetry and suggests the organic anode is controlled by a mixture of ion-diffusion and pseudocapacitive processes. Overall, these results reveal a new mechanistic understanding of the electrochemical behaviour in organic electrodes, as well as design features for their continued development.