Graphene-encapsulated blackberry-like porous silicon nanospheres prepared by modest magnesiothermic reduction for high-p
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Graphene-encapsulated blackberry-like porous silicon nanospheres prepared by modest magnesiothermic reduction for high-performance lithium-ion battery anode Ben Xiang, Wei-Li An, Ji-Jiang Fu, Shi-Xiong Mei, Si-Guang Guo, Xu-Ming Zhang, Biao Gao* , Paul K. Chu*
Received: 19 April 2020 / Revised: 29 May 2020 / Accepted: 9 July 2020 Ó The Nonferrous Metals Society of China and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Porous silicon (Si) nanostructures have aroused much interest as lithium-ion battery anodes because of the large space to accommodate the volume change in lithiation and delithiation and shorter ion transfer distance. However, fabrication of porous structures tends to be difficult to control and complex, so, the final electrochemical performance can be compromised. Herein, a modest magnesiothermic reduction (MMR) reaction is demonstrated to produce blackberry-like porous Si nanospheres (PSSs) controllably using magnesium silicide (Mg2Si) as Mg source and SiO2 nanospheres as the reactant. This improved MR Ben Xiang and Wei-Li An have contributed equally to this work.
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12598-020-01528-9) contains supplementary material, which is available to authorized users. B. Xiang, J.-J. Fu, S.-X. Mei, S.-G. Guo, X.-M. Zhang, B. Gao* The State Key Laboratory of Refractories and Metallurgy, Institute of Advanced Materials and Nanotechnology, Wuhan University of Science and Technology, Wuhan 430081, China e-mail: [email protected] W.-L. An BTR New Material Group Co., Ltd., Shenzhen 518106, China B. Gao, P. K. Chu* Department of Physics, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong, China e-mail: [email protected] P. K. Chu Department of Materials Science and Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong, China P. K. Chu Department of Biomedical Engineering, City University of Hong Kong, Tat Chee Avenue, Kowloon 999077, Hong Kong, China
method provides good control of the kinetics and heat release compared to the traditional MR (TMR) method using Mg powder as the reactant. The PSSs obtained by MMR reaction has higher structural integrity than that fabricated by TMR. After encapsulation with reduced graphene oxide, the Si/C composite exhibits superior cycling stability and rates such as a high reversible capacity of 1034 mAhg-1 at 0.5C (4200 mAhg-1 at 1.0C) after 1000 cycles, capacity retention of 79.5%, and high rate capacity of 497 mAhg-1 at 2.0C. This strategy offers a new route to fabricate highperformance porous Si anodes and can be extended to other materials such as germanium. Keywords Porous silicon; Graphene; Anode; Magnesiothermic reduction; Lithium-ion battery
1 Introduction Faster, lighter, smaller and more powerful rechargeable lithium-ion batteries (LIBs) are crucial to electric vehicles and portable electronic devices [1–3] and a myriad of anode materials have been developed and
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