Elucidating surface redox charge storage of phosphorus-incorporated graphenes with hierarchical architectures

Abstract

The incorporation of heteroatoms into carbon nanomaterials is extremely crucial for tuning their electronic and surface properties, but phosphorus (P) incorporation into hierarchical structure remains challenging and its charge storage mechanism is obscure. Herein, we investigate surface redox charge storage of hierarchically structured, P-incorporated graphene architectures (hpGAs). As probed by in-situ and ex-situ spectroscopic techniques and density functional theory, the P=O site of C–P=O bonding with the most favorable proton binding energy is identified and associated with highly reversible and fast pseudocapacitive behavior. As a consequence of synergistic effects arising from compositional and structural features, the hpGAs show dramatic improvements in capacitance, rate capability, and cyclic stability. This work broadens our knowledge about the unique surface charge storage phenomenon originating from the controlled heteroatom chemistry using combined spectroscopic and computational methods.