Biomass-Derived Hard Carbon with Interlayer Spacing Optimization toward Ultrastable Na-Ion Storage

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hard carbons are promising anode materials for sodium-ion batteries (SIBs) due to their large interlayer spacing.
• Current challenges include complex synthesis methods and unclear working mechanisms, hindering practical SIB applications.

Purpose of the Study:

• To report a facile production of tubular hard carbon from platanus flosses (FHC) for SIBs.
• To investigate the optimal pyrolysis temperature for FHC synthesis.
• To elucidate the sodium ion storage mechanism in FHC.

Main Methods:

• Direct carbonization of platanus flosses at optimized pyrolysis temperatures (up to 1300 °C).
• Electrochemical characterization including reversible capacity, rate capability, and cycling stability tests.
• In situ Raman spectroscopy to study the sodium ion storage mechanism.

Main Results:

• Optimized FHC at 1300 °C demonstrated a balance between interlayer spacing and surface area.
• Achieved a reversible capacity of 324.6 mAh g⁻¹ with a high initial Coulombic efficiency of 80%.
• Exhibited excellent rate performance (107.2 mAh g⁻¹ at 2 A g⁻¹) and stability over 1000 cycles.
• In situ Raman studies confirmed a sodium ion storage mechanism involving 'adsorption-insertion'.

Conclusions:

• Facile production of high-performance tubular hard carbon anodes from biomass is achievable.
• Optimized FHC offers a promising solution for advanced sodium-ion battery anodes.
• This work provides a scalable route for biomass-derived carbon anodes in high-performance SIBs.