Interface ion-exchange strategy of MXene@FeIn2S4 hetero-structure for super sodium ion half/full batteries
Mengqi Wang, Binyang Qin, Shimei Wu, Yining Li, Chilin Liu, Yufei Zhang, Lingxing Zeng, Haosen Fan
Abstract
Herein, a well-designed hierarchical architecture of bimetallic transition sulfide FeIn 2 S 4 nanoparticles anchoring on the Ti 3 C 2 MXene flakes has been prepared by cation exchange and subsequent high-temperature sulfidation processes. The introduction of MXene substrate with excellent conductivity not only accelerates the migration rate of Na + to achieve fast reaction dynamics but provides abundant deposition sites for the FeIn 2 S 4 nanoparticles . In addition, this hierarchical structure of MXene@FeIn 2 S 4 can effectively restrain the accumulation of MXene to guarantee the maximized exposure of redox active sites into the electrolyte, and simultaneously relieve the volume expansion in the repeated discharging/charging processes. The MXene@FeIn 2 S 4 displays outstanding rate capability (448.2 mAh g −1 at 5 A g −1 ) and stable long cycling performance (428.1 mAh g −1 at 2 A g −1 after 200 cycles). Moreover, the Na y -In 6 S 7 phase detected by ex-situ XRD and XPS characterization may be regarded as a “buffer” to maintain the stability of the Fe-based components and enhance the reversibility of the electrochemical reaction . This work confirms the practicability of constructing the hierarchical structure bimetallic sulfides with the promising electrochemical performance .