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Few‐Layer Bismuthene with Anisotropic Expansion for High‐Areal‐Capacity Sodium‐Ion Batteries
Author(s) -
Zhou Jing,
Chen Jiangchun,
Chen Mengxue,
Wang Jun,
Liu Xiaozhi,
Wei Bin,
Wang Zhongchang,
Li Junjie,
Gu Lin,
Zhang Qinghua,
Wang Hua,
Guo Lin
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201807874
Subject(s) - materials science , anode , bismuth , electrode , electrochemistry , energy storage , graphene , composite number , capacity loss , layer (electronics) , nanotechnology , optoelectronics , chemical engineering , composite material , metallurgy , power (physics) , chemistry , physics , engineering , quantum mechanics
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.