Pecher Oliver, Halat David M, Lee Jeongjae, Liu Zigeng, Griffith Kent J, Braun Marco, Grey Clare P
University of Cambridge, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK.
NMR Service GmbH, Blumenstr. 70, 99092 Erfurt, Germany.
J Magn Reson. 2017 Feb;275:127-136. doi: 10.1016/j.jmr.2016.12.008. Epub 2016 Dec 23.
We have developed and explored an external automatic tuning/matching (eATM) robot that can be attached to commercial and/or home-built magic angle spinning (MAS) or static nuclear magnetic resonance (NMR) probeheads. Complete synchronization and automation with Bruker and Tecmag spectrometers is ensured via transistor-transistor-logic (TTL) signals. The eATM robot enables an automated "on-the-fly" re-calibration of the radio frequency (rf) carrier frequency, which is beneficial whenever tuning/matching of the resonance circuit is required, e.g. variable temperature (VT) NMR, spin-echo mapping (variable offset cumulative spectroscopy, VOCS) and/or in situ NMR experiments of batteries. This allows a significant increase in efficiency for NMR experiments outside regular working hours (e.g. overnight) and, furthermore, enables measurements of quadrupolar nuclei which would not be possible in reasonable timeframes due to excessively large spectral widths. Additionally, different tuning/matching capacitor (and/or coil) settings for desired frequencies (e.g.Li and P at 117 and 122MHz, respectively, at 7.05 T) can be saved and made directly accessible before automatic tuning/matching, thus enabling automated measurements of multiple nuclei for one sample with no manual adjustment required by the user. We have applied this new eATM approach in static and MAS spin-echo mapping NMR experiments in different magnetic fields on four energy storage materials, namely: (1) paramagnetic Li and P MAS NMR (without manual recalibration) of the Li-ion battery cathode material LiFePO; (2) paramagnetic O VT-NMR of the solid oxide fuel cell cathode material LaNiO; (3) broadband Nb static NMR of the Li-ion battery material BNbO; and (4) broadband static I NMR of a potential Li-air battery product LiIO. In each case, insight into local atomic structure and dynamics arises primarily from the highly broadened (1-25MHz) NMR lineshapes that the eATM robot is uniquely suited to collect. These new developments in automation of NMR experiments are likely to advance the application of in and ex situ NMR investigations to an ever-increasing range of energy storage materials and systems.
我们开发并探索了一种外部自动调谐/匹配（eATM）机器人，它可以连接到商用和/或自制的魔角旋转（MAS）或静态核磁共振（NMR）探头。通过晶体管-晶体管逻辑（TTL）信号确保与布鲁克和泰克马格光谱仪完全同步和自动化。eATM机器人能够对射频（rf）载波频率进行自动“实时”重新校准，这在需要对谐振电路进行调谐/匹配时非常有用，例如变温（VT）NMR、自旋回波映射（可变偏移累积光谱，VOCS）和/或电池的原位NMR实验。这使得非工作时间（如过夜）的NMR实验效率大幅提高，此外，还能测量四极核，由于谱宽过大，在合理时间内无法进行此类测量。此外，可以保存所需频率（例如在7.05 T时分别为117 MHz和122 MHz的Li和P）的不同调谐/匹配电容器（和/或线圈）设置，并在自动调谐/匹配之前直接访问，从而实现对一个样品的多个核的自动测量，用户无需手动调整。我们已将这种新的eATM方法应用于四种储能材料在不同磁场下的静态和MAS自旋回波映射NMR实验，即：（1）锂离子电池正极材料LiFePO的顺磁性Li和P MAS NMR（无需手动重新校准）；（2）固体氧化物燃料电池正极材料LaNiO的顺磁性O VT-NMR；（3）锂离子电池材料BNbO的宽带Nb静态NMR；以及（4）潜在锂空气电池产品LiIO的宽带静态I NMR。在每种情况下，对局部原子结构和动力学的洞察主要来自eATM机器人特别适合收集的高度展宽（1 - 25 MHz）的NMR线形。NMR实验自动化方面的这些新进展可能会推动原位和非原位NMR研究在越来越多的储能材料和系统中的应用。
