Pore Structure Engineering Enables Synergistic Interfacial-Bulk Kinetics in Hard Carbon for High-Rate Sodium-Ion...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hard carbon anodes are cost-effective for sodium-ion batteries (SIBs) but suffer from low initial Coulombic efficiency (ICE) and poor cycle stability.
• Commercialization of SIBs is hindered by performance limitations of current anode materials under demanding conditions.

Purpose of the Study:

• To develop a multiscale porous ZHC anode with enhanced interfacial and bulk properties for improved SIB performance.
• To investigate the effects of physical and chemical modulation using organic compounds on anode structure and electrochemical behavior.

Main Methods:

• Synthesis of a multiscale porous ZHC anode using organic compounds for simultaneous interfacial and bulk regulation.
• Characterization of pore structure, including micropore/mesopore size, specific interface area, and closed-pore radius.
• Electrochemical testing of the ZHC anode in SIBs at various temperatures and current densities.

Main Results:

• The ZHC anode exhibited increased micropore/mesopore size, specific interface area, and structural disorder, with a closed-pore radius of 0.82 nm.
• Achieved high ICE values of 88.32% (25 °C), 82.76% (-10 °C), and 93.26% (50 °C).
• Demonstrated a capacity of 244.52 mAh g⁻¹ at 0.5 A g⁻¹ and 50 °C with 77.17% retention after 300 cycles; ZHC||NVP cell delivered 251.47 mAh g⁻¹.

Conclusions:

• Synergistic interfacial-bulk regulation via pore structure engineering significantly enhances interfacial-bulk kinetics in ZHC anodes.
• The developed ZHC anode shows excellent electrochemical performance, addressing key limitations of hard carbon anodes for SIBs.
• This study provides valuable experimental guidance for designing high-power SIBs through optimized anode pore structures.