Biomass-Derived Hard Carbon Anodes Processed with Deep Eutectic Solvents for High-Performance Sodium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Green Chemistry

Background:

• Sodium-ion batteries (SIBs) are a promising alternative for large-scale energy storage due to abundant sodium resources.
• Hard carbon is a leading anode material for SIBs, but its synthesis often involves environmentally challenging acids or alkalis.
• There is a need for cost-effective and sustainable methods to produce hard carbon anodes.

Purpose of the Study:

• To develop a universal, cost-effective, and environmentally friendly method for synthesizing high-performance hard carbon anodes from biomass.
• To investigate the use of biomass-derived deep eutectic solvents (DES) for modifying hard carbon structure and properties.
• To demonstrate the versatility of the method across various biomass feedstocks.

Main Methods:

• A reciprocal biomass processing method utilizing biomass-based deep eutectic solvents (DES) was developed.
• DES treatment disrupted hydrogen bonds in cellulose, increasing disorder and interlayer spacing during pyrolysis.
• Hard carbon anodes were synthesized from various biomass sources, including macadamia nut shells, bamboo, coconut, and pine.

Main Results:

• The optimal hard carbon anode from macadamia nut shells (MNSs) showed a high reversible capacity of 297.07 mAh g^-1 at 20 mA g^-1.
• DES treatment enhanced sodium-ion transport and storage capabilities in the hard carbon anodes.
• The method proved versatile, yielding high-performance anodes from diverse biomass resources.

Conclusions:

• The developed method offers a universal and green approach for synthesizing high-performance hard carbon anodes from biomass.
• This sustainable method addresses the environmental and cost challenges associated with traditional hard carbon anode production.
• The findings support the use of biomass-derived materials for advanced energy storage solutions like SIBs.