Tuning Microstructures of Hard Carbon Anode by Rapid Pre-foaming Strategy for Superhigh-Rate Sodium-ion Storage Performance in Low-plateau Region
Prof. Zhihua Xiao, Zechen Li, Yankun Sun, Fangzhi Zheng, Chong Xu, Dong Sun, Shuang Liu, Bo Sun, Ziang Wang, Sijia Liao, Taoyuan Pan, Qiang Ye, Tao Li, Ping Xu, Ping Li
Abstract
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.