Designing the Precursor Structure Through Composite Engineering for Achieving High-Capacity Lignin-Derived Hard...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Hard carbon anodes are crucial for sodium-ion batteries, offering abundant sodium-ion storage sites due to their curved graphene sheets and cross-linked structures.
• Enhancing sodium-ion storage performance requires precursors that yield hard carbons with larger interlayer spacing and more closed-pore structures.
• Alkali lignin (AL) is a promising biomass precursor, but its inherent aggregate structure limits the formation of desired microstructures during carbonization.

Purpose of the Study:

• To develop a novel hard carbon anode material for sodium-ion batteries with improved sodium-ion storage performance.
• To overcome the limitations of alkali lignin as a precursor by modifying its aggregate structure.
• To engineer the microstructure of lignin-derived hard carbon for enhanced electrochemical properties.

Main Methods:

• A lignin-polyaniline composite (AL/PANI) was synthesized via intermolecular interactions between alkali lignin (AL) and polyaniline (PANI).
• The AL/PANI composite was subjected to one-step high-temperature carbonization to produce lignin-polyaniline-derived hard carbon (LPHC).
• The structural changes and electrochemical performance of the resulting LPHC were characterized.

Main Results:

• The polyaniline component disrupted the aggregate structure of lignin, leading to hard carbon with enlarged interlayer spacing and a rich closed-pore structure.
• The synthesized LPHC exhibited a high specific capacity of 360 mAh g^-1 at 0.1 A g^-1.
• A significant plateau-potential capacity of 250 mAh g^-1 was achieved, demonstrating excellent sodium-ion storage capability.

Conclusions:

• Utilizing guest molecules like polyaniline to regulate the composite structure of lignin is an effective strategy for tailoring hard carbon microstructure.
• This approach enables the fabrication of high-performance hard carbon anode materials derived from biomass for sodium-ion batteries.
• The study highlights a promising route for structure engineering of lignin-derived carbons for advanced energy storage applications.