Few‐Layer Bismuthene with Anisotropic Expansion for High‐Areal‐Capacity Sodium‐Ion Batteries

Bismuth is a promising anode material for state‐of‐the‐art rechargeable batteries due to its high theoretical volumetric capacity and relatively low working potential. However, its charge storage mechanism is unclear, hindering further improvement of the cell performance. Here, using in situ transmi...

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Bibliographic Details
Published in:Advanced materials (Weinheim) 2019-03, Vol.31 (12), p.e1807874-n/a
Main Authors: Zhou, Jing, Chen, Jiangchun, Chen, Mengxue, Wang, Jun, Liu, Xiaozhi, Wei, Bin, Wang, Zhongchang, Li, Junjie, Gu, Lin, Zhang, Qinghua, Wang, Hua, Guo, Lin
Format: Article
Language:English
Subjects:
anisotropic expansion
Anisotropy
Anodes
areal capacity
Aspect ratio
Batteries
Bismuth
bismuthene
Electrochemical analysis
Electrode materials
Electrodes
Energy storage
Graphene
Materials science
Rechargeable batteries
Sodium-ion batteries
sodium‐ion battery
Storage capacity
Transmission electron microscopy
X-ray diffraction
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Summary:Bismuth is a promising anode material for state‐of‐the‐art rechargeable batteries due to its high theoretical volumetric capacity and relatively low working potential. However, its charge storage mechanism is unclear, hindering further improvement of the cell performance. Here, using in situ transmission electron microscopy and X‐ray diffraction techniques as well as theoretical analysis, it is found that a large anisotropic volume expansion of 142% occurs along the z‐axis largely due to the alloy reaction during sodiation, significantly reducing the electrochemical performance of bismuth electrodes. To address this problem, ultrathin few‐layer bismuthene with a large aspect ratio is rationally synthesized, and can relieve the expansion strain along the z‐axis. A free‐standing bismuthene/graphene composite electrode with tunable thickness achieves a strikingly stable and high areal sodium storage capacity of 12.1 mAh cm−2, which greatly exceeds that of most reported electrode materials. The clarification of the charge storage mechanism and the superior areal capacity achieved should facilitate the development of bismuth‐based high‐performance anodes for practical electrochemical energy‐storage applications. The charge storage mechanism of a bismuth electrode with a large anisotropic volume expansion along the z‐axis is investigated by in situ techniques. A bismuthene/graphene composite electrode, which can relieve expansion strain along the z‐axis, is rationally designed and shows a strikingly stable and high areal sodium‐storage capacity with promise for practical applications.
ISSN:0935-9648
1521-4095
DOI:10.1002/adma.201807874