1. Composition-dependent lithium storage performances of SnS/SnO2 heterostructures sandwiching between spherical graphene.
- Author
-
Zhao, Bing, Zhuang, Hua, Yang, Yaqing, Wang, Yanyan, Tao, Haihua, Wang, Zhixuan, Jiang, Jinlong, Chen, Zhiwen, Huang, Shoushuang, and Jiang, Yong
- Subjects
- *
LITHIUM , *ELECTROCHEMICAL electrodes , *COMPOSITE structures - Abstract
Abstract Heterostructures have broad potential application in energy conversion material and optoelectronic device since of novel interface effect and enhanced electron transport dynamics at heterointerfaces. Herein, we report a heterostructured SnS/SnO 2 /spherical graphene composite, in which ultrafine SnS/SnO 2 nanoparticles with heterostructures are sandwiched between multi-layers of graphene sheets, exhibiting a hollow spherical architecture as a whole. Detailed electrochemical studies indicate that the molar ratio of SnS to SnO 2 has great influence on the charge transport efficiency. Theoretical calculation reveals that SnS and SnO 2 exhibit different work functions and the Fermi level shift is affected by the SnS/SnO 2 molar ratio, thus the hybrid with the ratio close to 1.0 owns the most adsorbed lithium ions, which leads to the highest specific charge-transfer kinetics and lowest ion-diffusion resistance than other samples. Electrochemical tests show that the composite with appropriate composition delivers the best lithium storage rate performance (620 and 312.7 mAh g−1 at 1 C and 10 C). A much stable and high reversible specific capacity of 850 mAh g−1 is obtained after 200 cycles at 0.1 C. The appropriate molar ratio of nano-heterostructures and the novel sandwich hollow spherical composite structure are attributed to the excellent electrochemical performances. Graphical abstract Image 1 Highlights • Heterostructured SnS/SnO 2 /spherical graphene composite is prepared. • Ultrafine SnS/SnO 2 nanoheterostructures are sandwiched between graphene shells. • Fermi level shift is influenced by SnS/SnO 2 molar ratio via DTF calculation. • The composite with molar ratio close to 1 exhibits best charge transfer capability. • Excellent rate performance and cyclic stability is obtained in optimized sample. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF