Insights into Synergistic Effect of g-C3N4/Graphite Heterostructures for Boosting Sodium Ion Storage with Long Cycle Stability

Sodium-ion batteries (SIBs) have attracted significant attention as promising next-generation energy storage devices. However, the research and development of SIBs are still in their infancy due to the lack of suitable high-performance anode materials. As a commercial anode material for lithium-ion batteries (LIBs), graphite often shows a low sodium storage capacity. Herein, a graphite heterojunction material was prepared through a facile ball-milling method. During the ball-milling process, a defect-enriched g-C3N4/graphite heterojunction was formed and the nitrogen-containing functional groups were regulated, which promoted the sodium storage capacity. The resulting g-C3N4/graphite electrode can exhibit excellent long cycle stability and rate performance, delivering a high reversible capacity of 202 mAh g(-1) at 1.0 A g(-1) after 6000 cycles and 90.06 mAh g(-1) at 5.0 A g(-1) after 10000 cycles. Moreover, an ultrahigh rate capability can also be obtained at 1.0 A g(-1) with a capacity of 111 mAh The superiority of heterostructures for sodium storage and diffusion was proved via DFT calculations, which verified the synergistic effect between graphite and g-C3N4. This study provides a simple and efficient method for preparing g-C3N4/graphite heterostructures as well as a deep insight into the sodium storage mechanism of a heterostructure anode.

Automated summary

This study presents a facile method to prepare graphite heterojunction material, which enhances the sodium storage capacity. The resulting electrode exhibits excellent long cycle stability and rate performance. DFT calculations confirm the superiority of heterostructures for sodium storage and diffusion. This research provides a simple and efficient approach for the preparation of g-C3N4/graphite heterostructures, and offers insights into the sodium storage mechanism of a heterostructure anode.