Hierarchically Porous P ₂ O ₅ ‐Modified Soft Carbon From Petroleum Pitch: Preparation and Lithium Storage Properties

ABSTRACT Petroleum pitch, a soft‐carbon precursor rich in aromatics, facilitates the formation of graphitic microdomains, thereby enhancing lithium‐ion (Li + ) diffusion and structural stability. In this work, a P 2 O 5 ‐assisted method was developed to simultaneously cross‐link the molecular chains of pitch and introduce phosphorus dopants, yielding a carbon material with an expanded interlayer spacing (0.361 nm), increased structural disorder, and a hierarchical porous texture. The P 2 O 5 ‐induced cross‐linking disrupted the layer ordering, increased the specific surface area and porosity, and created additional Li + migration pathways. Moreover, phosphorus doping increased the interlayer spacing via enhanced interlayer repulsion, thereby accelerating Li + transport. Consequently, the material delivered an initial charge capacity of 578 mA h g 1 and retained 94% of its capacity after 1000 cycles at a current density of 0.5 A g −1 . In situ Fourier transform infrared (FTIR) and wettability measurements revealed a rough, pore‐rich surface that improved electrode‐electrolyte wettability and facilitated Li + desolvation, thereby contributing to the enhanced cycling stability. Overall, phosphorus doping significantly enhances the lithium storage performance of pitch‐derived soft carbon and provides a viable route for the resource utilization of petroleum pitch.