Proton and Li-Ion Permeation through Graphene with Eight-Atom-Ring Defects
Proton and Li-Ion Permeation through Graphene with Eight-Atom-Ring Defects
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DOI：
10.1021/acsnano.0c02496
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发表时间：
2020-06-23
期刊：
影响因子：
17.1
通讯作者：
Lozada-Hidalgo, Marcelo
中科院分区：
文献类型：
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作者：
Griffin, Eoin;Mogg, Lucas;Lozada-Hidalgo, Marcelo
无缺陷的石墨烯对气体和液体是不可渗透的，但对热质子是高度可渗透的。原子级缺陷，如空位，晶界和斯通-威尔士缺陷，预计将提高石墨烯的质子渗透性，甚至可能允许小离子通过，而较大的物种，如气体分子应保持封锁。到目前为止，这些期望尚未在实验中得到验证。在这里，我们发现具有高密度原子级缺陷的原子级薄碳膜继续阻止所有分子传输，但它们的质子渗透性比无缺陷石墨烯高出1000倍。锂离子也可以渗透通过这种无序的石墨烯。增强的质子和离子渗透性归因于高密度的八碳原子环。与石墨烯的六原子环相比，后者对进入的质子造成大约两倍低的能量势垒，并且对Li离子造成类似于0.6 eV的相对低的势垒。我们的研究结果表明，无序石墨烯可以作为各种锂离子和氢技术中的膜和保护屏障。
Defect-free graphene is impermeable to gases and liquids but highly permeable to thermal protons. Atomic-scale defects such as vacancies, grain boundaries, and Stone-Wales defects are predicted to enhance graphene's proton permeability and may even allow small ions through, whereas larger species such as gas molecules should remain blocked. These expectations have so far remained untested in experiment. Here, we show that atomically thin carbon films with a high density of atomic-scale defects continue blocking all molecular transport, but their proton permeability becomes similar to 1000 times higher than that of defect-free graphene. Lithium ions can also permeate through such disordered graphene. The enhanced proton and ion permeability is attributed to a high density of eight-carbon-atom rings. The latter pose approximately twice lower energy barriers for incoming protons compared to that of the six-atom rings of graphene and a relatively low barrier of similar to 0.6 eV for Li ions. Our findings suggest that disordered graphene could be of interest as membranes and protective barriers in various Li-ion and hydrogen technologies.