Selective NMR observation of the SEI-metal interface by dynamic nuclear polarisation from lithium metal
Selective NMR observation of the SEI-metal interface by dynamic nuclear polarisation from lithium metal
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DOI：
10.1038/s41467-020-16114-x
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发表时间：
2020-05-06
影响因子：
16.6
通讯作者：
Grey, Clare P.
中科院分区：
文献类型：
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作者：
Hope, Michael A.;Rinkel, Bernardine L. D.;Grey, Clare P.
虽然锂金属代表了最终的高能量密度电池负极材料，但它的使用受到枝晶形成和相关安全风险的限制，这促使人们对锂上形成的固体电解质间相层进行研究，这是控制锂金属沉积的关键。动态核极化增强核磁共振可以提供重要的结构信息；然而，在典型的外源动态核极化实验中，将有机自由基添加到样品中，需要低温冷却样品，并且对金属和固体-电解质界面之间的界面没有选择性。在这里，我们利用锂金属的传导电子来实现室温下数量级的超极化。我们选择性地增强了固体电解质间相物质的Li-7、H-1和F-19核磁共振谱，揭示了它们的化学性质和空间分布。这些实验为更雄心勃勃的室温原位动态核极化电池研究和在更广泛的系统中选择性增强金属-固体界面铺平了道路。了解固体电解质间相（SEI）是开发安全无枝晶锂电池的关键。在这里，通过利用金属锂中的电子选择性地超极化核磁共振信号，作者揭示了金属- sei界面上物质的化学和空间分布。
While lithium metal represents the ultimate high-energy-density battery anode material, its use is limited by dendrite formation and associated safety risks, motivating studies of the solid-electrolyte interphase layer that forms on the lithium, which is key in controlling lithium metal deposition. Dynamic nuclear polarisation enhanced NMR can provide important structural information; however, typical exogenous dynamic nuclear polarisation experiments, in which organic radicals are added to the sample, require cryogenic sample cooling and are not selective for the interface between the metal and the solid-electrolyte interphase. Here we instead exploit the conduction electrons of lithium metal to achieve an order of magnitude hyperpolarisation at room temperature. We enhance the Li-7, H-1 and F-19 NMR spectra of solid-electrolyte interphase species selectively, revealing their chemical nature and spatial distribution. These experiments pave the way for more ambitious room temperature in situ dynamic nuclear polarisation studies of batteries and the selective enhancement of metal-solid interfaces in a wider range of systems. Understanding the solid-electrolyte interphase (SEI) is key to developing safe dendrite-free lithium batteries. Here, by exploiting the electrons in lithium metal to selectively hyperpolarise the NMR signals, the authors reveal the chemistry and spatial distribution of species at the metal-SEI interface.