Hierarchically Porous P₂O₅-Modified Soft Carbon From Petroleum Pitch: Preparation and Lithium Storage Properties

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Petroleum pitch is a promising precursor for soft carbon materials due to its aromatic structure, which aids in forming graphitic microdomains.
• Enhancing lithium-ion (Li+) diffusion and structural stability in soft carbon is crucial for high-performance lithium-ion batteries.
• Developing efficient methods for modifying petroleum pitch can unlock its potential for advanced energy storage applications.

Purpose of the Study:

• To develop a P₂O₅-assisted method for simultaneously cross-linking petroleum pitch and introducing phosphorus dopants.
• To investigate the impact of this modification on the carbon material's structure, porosity, and electrochemical performance.
• To evaluate the potential of pitch-derived soft carbon as an anode material for lithium-ion batteries.

Main Methods:

• A P₂O₅-assisted cross-linking and doping strategy was employed on petroleum pitch.
• Characterization techniques including analysis of interlayer spacing, structural disorder, and porosity were utilized.
• Electrochemical performance was assessed through charge capacity, cycling stability, and current density measurements.
• In situ Fourier transform infrared (FTIR) spectroscopy and wettability tests were performed.

Main Results:

• The P₂O₅ treatment yielded a carbon material with expanded interlayer spacing (0.361 nm), increased structural disorder, and a hierarchical porous texture.
• Cross-linking disrupted layer ordering, increasing specific surface area and porosity, creating additional Li+ migration pathways.
• Phosphorus doping accelerated Li+ transport by increasing interlayer spacing.
• The material exhibited an initial charge capacity of 578 mA h g^-1 and retained 94% capacity after 1000 cycles at 0.5 A g^-1.
• Improved electrode-electrolyte wettability and Li+ desolvation were observed.

Conclusions:

• The P₂O₅-assisted method effectively enhances the lithium storage performance of petroleum pitch-derived soft carbon.
• The modified material demonstrates excellent capacity, cycling stability, and Li+ transport kinetics.
• This approach offers a viable route for the resource utilization of petroleum pitch in advanced battery technologies.