Developing bifunctional electrocatalytic materials for the oxygen evolution reaction (OER) and supercapacitors in acidic environments is pivotal for advancing energy conversion and storage technologies. However, this task remains challenging owing to the corrosive environment and sluggish reaction kinetics. In this study, we report a novel self-assembly in situ doping strategy to develop a metal-free phosphorus-modified nitrogen-doped carbon (P-NG) bifunctional material.