Protecting Silicon Film Anodes in Lithium-Ion Batteries Using an Atomically Thin Graphene Drape
Protecting Silicon Film Anodes in Lithium-Ion Batteries Using an Atomically Thin Graphene Drape
复制标题
DOI：
10.1021/acsnano.7b01780
复制
发表时间：
2017-05-01
期刊：
影响因子：
17.1
通讯作者：
Koratkar, Nikhil
中科院分区：
文献类型：
--
作者：
Suresh, Shravan;Wu, Zi Ping;Koratkar, Nikhil
硅（Si）由于其非常高的比容量而显示出作为锂离子电池中的阳极材料的前景。然而，Si是高度易碎的，并且为了防止Si断裂，研究界已经从使用Si膜迁移到基于Si纳米颗粒的电极。然而，由于Si纳米颗粒电极的多孔性，这种策略显著降低了体积能量密度。在这里，我们表明，与传统的智慧，硅膜可以通过两种策略来稳定：（a）锚定的硅膜的碳纳米管宏膜（CNM）集流体和（B）覆盖的膜与石墨烯单层。在电化学循环之后，CNM上的石墨烯涂覆的Si膜类似于坚韧的泥裂表面，其中石墨烯覆盖层抑制分层并稳定固体电解质界面。在CNM上的石墨烯覆盖的Si膜表现出长的循环寿命（>1000个充电/放电步骤），平均比容量类似于806 mAh g（-1）。在1000次充电/放电循环中平均的体积容量类似于2821 mAh cm（-3），这比文献中报道的基于Si纳米颗粒的电极的体积容量高2至5倍。石墨烯覆盖的Si阳极也可以在全电池配置中相对于商业阴极成功地循环。
Silicon (Si) shows promise as an anode material in lithium-ion batteries due to its very high specific capacity. However, Si is highly brittle, and in an effort to prevent Si from fracturing, the research community has migrated from the use of Si films to Si nanoparticle based electrodes. However, such a strategy significantly reduces volumetric energy density due to the porosity of Si nanoparticle electrodes. Here we show that contrary to conventional wisdom, Si films can be stabilized by two strategies: (a) anchoring the Si films to a carbon nanotube macrofilm (CNM) current collector and (b) draping the films with a graphene monolayer. After electrochemical cycling, the graphene-coated Si films on CNM resembled a tough mud-cracked surface in which the graphene capping layer suppresses delamination and stabilizes the solid electrolyte interface. The graphene-draped Si films on CNM exhibit long cycle life (>1000 charge/discharge steps) with an average specific capacity of similar to 806 mAh g(-1). The volumetric capacity averaged over 1000 cycles of charge/discharge is similar to 2821 mAh cm(-3), which is 2 to 5 times higher than what is reported in the literature for Si nanoparticle based electrodes. The graphene-draped Si anode could also be successfully cycled against commercial cathodes in a full-cell configuration.