Graphene-encapsulated blackberry-like porous silicon nanospheres prepared by modest magnesiothermic reduction for high-performance lithium-ion battery anode
来源期刊：Rare Metals2021年第2期
论文作者：Ben Xiang Wei-Li An Ji-Jiang Fu Shi-Xiong Mei Si-Guang Guo Xu-Ming Zhang Biao Gao Paul K.Chu
文章页码：383 - 392
摘 要：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（Mg2 Si） as Mg source and SiO2 nanospheres as the reactant.This improved MR 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 mAh·g-1 at0.5 C(4200 mAh·g-1 at 1.0 C) after 1000 cycles,capacity retention of 79.5%,and high rate capacity of 497 mAh·g-1at 2.0 C.This strategy offers a new route to fabricate highperformance porous Si anodes and can be extended to other materials such as germanium.
Ben Xiang1，Wei-Li An2，Ji-Jiang Fu1，Shi-Xiong Mei1，Si-Guang Guo1，Xu-Ming Zhang1，Biao Gao1,3，Paul K.Chu3,4,5
1. The State Key Laboratory of Refractories and Metallurgy,Institute of Advanced Materials and Nanotechnology,Wuhan University of Science and Technology2. BTR New Material Group Co.,Ltd.3. Department of Physics,City University of Hong Kong4. Department of Materials Science and Engineering,City University of Hong Kong5. Department of Biomedical Engineering,City University of Hong Kong
摘 要：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（Mg2 Si） as Mg source and SiO2 nanospheres as the reactant.This improved MR 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 mAh·g-1 at0.5 C(4200 mAh·g-1 at 1.0 C) after 1000 cycles,capacity retention of 79.5%,and high rate capacity of 497 mAh·g-1at 2.0 C.This strategy offers a new route to fabricate highperformance porous Si anodes and can be extended to other materials such as germanium.
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