Affiliation:
1. State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of Chemistry Xinjiang University Urumqi 830017 P. R. China
2. College of Chemistry Zhengzhou University Zhengzhou Henan Province 450001 P. R. China
3. Shanxi Supercomputing Center Lvliang 033000 P. R. China
4. National Supercomputing Center in Zhengzhou Zhengzhou 450001 P. R. China
5. School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 P. R. China
6. Institute of Theoretical Physics Lanzhou University Lanzhou 730000 P. R. China
Abstract
AbstractLayered indium selenide (InSe) is a new 2D semiconductor material with high carrier mobility, widely adjustable bandgap, and high ductility. However, its ion storage behavior and related electrochemical reaction mechanism are rarely reported. In this study, InSe nanoflakes encapsulated in conductive polypyrrole (InSe@PPy) are designed in consideration of restraining the severe volume change in the electrochemical reaction and increasing conductivity via in situ chemical oxidation polymerization. Density functional theory calculations demonstrate that the construction of heterostructure can generate an internal electric field to accelerate electron transfer via additional driving forces, offering synergistically enhanced structural stability, electrical conductivity, and Na+ diffusion process. The resulting InSe@PPy composite shows outstanding electrochemical performance in the sodium ion batteries system, achieving a high reversible capacity of 336.4 mA h g−1 after 500 cycles at 1 A g−1 and a long‐term cyclic stability with capacity of 274.4 mA h g−1 after 2800 cycles at 5 A g−1. In particular, the investigation of capacity fluctuation within the first cycling reveals the alternating significance of intercalation and conversion reactions and evanescent alloying reaction. The combined reaction mechanism of insertion, conversion, and alloying of InSe@PPy is revealed by in situ X‐ray diffraction, ex situ electrochemical impedance spectroscopy, and transmission electron microscopy.
Funder
Natural Science Foundation of Henan Province
National Natural Science Foundation of China
Subject
Biomaterials,Biotechnology,General Materials Science,General Chemistry