Hope Michael A, Rinkel Bernardine L D, Gunnarsdóttir Anna B, Märker Katharina, Menkin Svetlana, Paul Subhradip, Sergeyev Ivan V, Grey Clare P
Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
Nat Commun. 2020 May 6;11(1):2224. doi: 10.1038/s41467-020-16114-x.
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, H and F 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.
虽然锂金属是终极的高能量密度电池负极材料，但其应用受到枝晶形成和相关安全风险的限制，这激发了对锂表面形成的固体电解质界面层的研究，该界面层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，典型的外源性动态核极化实验是在样品中添加有机自由基，需要对样品进行低温冷却，并且对金属与固体电解质界面没有选择性。在此，我们转而利用锂金属的传导电子在室温下实现了一个数量级的超极化。我们选择性地增强了固体电解质界面物种的锂、氢和氟核磁共振谱，揭示了它们的化学性质和空间分布。这些实验为更具雄心的室温原位电池动态核极化研究以及更广泛系统中金属-固体界面的选择性增强铺平了道路。
