Tuning Microstructures of Hard Carbon Anode by Rapid Pre-foaming Strategy for Superhigh-Rate Sodium-ion Storage Performance in Low-plateau Region

Fabricating suitable microstructures containing closed pore volume , closed pore size, interlayer spacing as well as C=O content in the glucose-based hard carbon (Glu-HC) can greatly enhance its electrochemical performance in sodium-ion batteries (SIBs) at low-voltage below 0.1 V. Unfortunately, the blistering nature of D-glucose makes it difficult to regulate precisely these microstructures for achieving an excellent Na + storage performance, especially at high rates. Herein, D-glucose was rational pretreated by modulating KMnO 4 addition and hot acid-washing time to promote its condensation and aromatization, and avoid a foaming phenomenon. During carbonization , a deep chemical cross-liking reaction can be generated in the pretreated D-glucose to obtain HC concurrently featuring with these favorable microstructures. The optimal HC anode (HC-1100) shows high initial coulombic efficiency (89.62%), large total capacity of 421.6 and 215.3 mAh g −1 at 0.1 and 20 A g −1 , respectively. Besides, it delivers high plateau capacities of 303.31 and 193.1 mAh g −1 at 0.1 and 5 A g −1 along with 87% capacity retention for 2000 cycles, far surpassing than these reported HC anodes. Additionally, the HC-1100//Na 3 V 2 (PO 4 ) 3 full cell exhibits high energy density of 194 Wh kg −1 . Furthermore, Na + storage behaviors and theoretical calculations demonstrates that the HC material owning high C=O content, suitable closed pore size (0.9 nm) and interlayer spacing (0.5 nm) possesses a superior ultrahigh-rate performance. This work provides a significative guidance for rational constructing high-performance HC anode. Glucose-based hard carbon with rich C=O group, high closed pore volume, suitable closed pore size and large interlayer spacing was precisely prepared by combining rapid pre-foaming and high-temperature carbonization strategy. As sodium-ion battery anode, it showed superhigh plateau capacities of 303.31 and 193.1 mAh g −1 at 0.1 and 5 A g −1 , far exceeding than that of commercial HC anode.