Bicontinuous Structure Mediated Microstructural Engineering of Hard Carbon for Enhanced Sodium Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) offer a low-cost alternative to lithium-ion batteries.
• Current SIBs face challenges like poor cycle stability and rate performance.
• Hard carbons are promising anodes but require microstructural optimization.

Purpose of the Study:

• To develop an advanced hard carbon anode for improved SIB performance.
• To address limitations of high irreversible capacity loss and poor kinetics.
• To investigate the impact of microstructural engineering on sodium storage.

Main Methods:

• Synthesis of a bicontinuous mesoporous hard carbon with a single primitive (SP) microstructure (SP-HC).
• Microstructural characterization to analyze pore structure and interlayer spacing.
• Electrochemical testing to evaluate capacity, rate performance, and cycle stability.

Main Results:

• The SP-HC anode demonstrated increased sodium storage site density and accessibility.
• Enhanced carbon disorder and expanded interlayer spacing were observed.
• Exceptional rate performance (172 mAh g⁻¹ at 10 A g⁻¹) and unprecedented cycle stability (80 mAh g⁻¹ after 100,000 cycles at 10 A g⁻¹) were achieved.

Conclusions:

• Microstructural engineering is critical for optimizing hard carbon anodes in SIBs.
• The SP-HC design significantly improves sodium storage capacity and kinetics.
• This work sets a new benchmark for cycle stability in hard carbon anodes for SIBs.