Revealing the closed pore formation of waste wood-derived hard carbon for advanced sodium-ion battery

Although the closed pore structure plays a key role in contributing low-voltage plateau capacity of hard carbon anode for sodium-ion batteries, the formation mechanism of closed pores is still under debate. Here, we employ waste wood-derived hard carbon as a template to systematically establish the formation mechanisms of closed pores and their effect on sodium storage performance. We find that the high crystallinity cellulose in nature wood decomposes to long-range carbon layers as the wall of closed pore, and the amorphous component can hinder the graphitization of carbon layer and induce the crispation of long-range carbon layers. The optimized sample demonstrates a high reversible capacity of 430 mAh g-1 at 20 mA g-1 (plateau capacity of 293 mAh g-1 for the second cycle), as well as good rate and stable cycling performances (85.4% after 400 cycles at 500 mA g-1). Deep insights into the closed pore formation will greatly forward the rational design of hard carbon anode with high capacity. It is essential to investigate the formation mechanism of closed pore, which contributes to low-voltage plateau capacity of hard carbon anode in sodium ion batteries. Herein, the authors explore the impact of wood precursor components and carbonization temperature on closed pore formation in hard carbon for enhanced battery performance.

Automated summary

The formation mechanism of closed pores in hard carbon anodes for sodium-ion batteries, using waste wood-derived hard carbon as a template, has been systematically established. The study shows that the high crystallinity cellulose in nature wood decomposes to form the walls of closed pores, impacting the carbon layer and influencing battery performance. The research provides insights into enhancing battery performance by understanding closed pore formation in hard carbon materials.