Asymmetric Membranes Containing Micron-Size Silicon for High Performance Lithium Ion Battery Anode

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• 作者：Ian Byrd ; Ji Wu ; ^{jwu@georgiasouthern.edu" class="auth_mail" title="E-mail the corresponding author} ; ^{jiwu666@gmail.com" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Micron-size silicon ; lithium ion battery anode ; high cyclability ; sandwich structure ; asymmetric membrane
• 刊名：Electrochimica Acta
• 出版年：2016
• 出版时间：20 September 2016
• 年：2016
• 卷：213
• 期：Complete
• 页码：46-54
• 全文大小：2391 K

文摘

Micron-size Si anode is notorious for having extremely poor cycle life. It is mainly caused by the large volume change (∼300%) and poor mechanical strength of the Si electrode. Satisfying methods to address this issue are seriously lacking in literature. In this study, novel single-layer, double-layer and triple-layer asymmetric membranes containing micron-size silicon have been fabricated using a simple phase inversion method to dramatically improve its cyclability. The electrochemical performance of these asymmetric membranes as lithium ion battery anodes are evaluated and compared to pure micron-size Si powders and carbonaceous asymmetric membranes. All three types of asymmetric membrane electrodes demonstrate significantly enhanced stability as compared to pure Si powders. The single-layer asymmetric membrane has the largest capacity degradation due to the loss of pulverized Si powders from the membrane surface, only 40% of whose capacity can be retained in 100 cycles. But this performance is still much better than pure micron-size silicon electrode. After being coated with nanoporous carbonaceous layers on both sides of a single-layer asymmetric membrane to make a triple-layer asymmetric membrane (sandwich structure), the capacity retention is notably increased to 88% in 100 cycles at 610 mAh g⁻¹ and 0.5C. The enhanced stability is attributed to the extra nanoporous coatings that can prevent the fractured Si powders from being leached out and allow facile lithium ion diffusions. Such a novel, efficient and scalable method may provide beneficiary guidance for designing high capacity lithium ion battery anodes with large volume change issues.