Achieving Enhanced Sodium Storage Performance of Hard Carbon via Rational Modification of a Starch Precursor

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Chemical modification of starch hydroxyl groups is crucial for optimizing hard carbon (HC) anode performance in sodium-ion batteries (SIBs).
• Controlling the complex microstructures of HC is challenging but essential for designing advanced sodium storage materials.

Purpose of the Study:

• To investigate the use of diammonium phosphate (DAP) as a cross-linking agent for corn starch to modify HC microstructures.
• To enhance the electrochemical performance of HC anodes for SIBs through controlled pore structure and interlayer spacing.

Main Methods:

• Corn starch was chemically modified using diammonium phosphate (DAP) as a cross-linking agent.
• The modified starch was pyrolyzed to produce hard carbon (HC) materials.
• Electrochemical performance of the modified HC (HC-10) was evaluated in SIBs.

Main Results:

• The optimized HC-10 exhibited superior electrochemical performance compared to unmodified HC.
• HC-10 achieved a high reversible capacity of 344.16 mAh g^-1 at 0.03 A g^-1.
• It demonstrated excellent rate capability (134.73 mAh g^-1 at 0.3 A g^-1) and cycle stability (98.5% retention after 500 cycles).

Conclusions:

• DAP modification effectively balances pore structure and interlayer spacing in HC, leading to enhanced sodium storage.
• DAP acts as a catalyst during pyrolysis, influencing carbon layer growth, defect formation, and pore structure.
• This study provides a valuable approach for developing high-performance biomass-derived anode materials for SIBs.