Benchtop Nuclear Magnetic Resonance Spectrometer for Analysis of Lithium-ion Battery Electrolytes

锂离子电池的电解质类似于动物的血液。随着电解质的降解，电池将开始失效。监测电解液的组成和电池充放电循环过程中电解液的变化，可以让人们了解电池失效的机制，然后纠正它们。这类似于用于诊断人类疾病的血液测试。我们的实验室大量使用核磁共振光谱来监测电池电解质的变化。这是目前在达尔豪斯核磁共振设施中完成的，那里使用了昂贵而稀有的液氦和大型核磁共振光谱仪。******此请求是用于台式核磁共振光谱仪，它使用永磁体，因此没有液氦。现代台式核磁共振光谱仪使用简单，价格低廉，高度坚固，可以从115V插座供电。收集高质量频谱所需的时间也非常短，大约几分钟。******我们的实验室每月制造超过1000个锂离子和“无阳极”袋式电池，用于各种测试。这些电池中的许多在测试后都要对其电解质进行核磁共振分析，甚至更大的一部分应该进行核磁共振分析。实验的结果非常有价值，在我的实验室里使用这种技术的学生现在有6人，而且还在迅速增长。进入达尔豪斯核磁共振设施被证明是不充分和不方便的。台式核磁共振系统将使我们能够提高生产力，从而提高我们制造高能量密度锂电池的能力，并延长使用寿命。我们最近的成功已经在媒体上得到了强调，例如：https://marker.medium.com/tesla-may-have-invented-a-million-mile-electric-car-battery-c3c11cc76d84 ******台式核磁共振光谱仪通常可以设置为能够测量三个核，我们将选择H， Li和f。H是电解质中使用的所有非水溶剂中的一个成分。当然，锂以盐的形式存在于电解质中。我们和其他人已经证明，在充电和放电循环的某些条件下，锂离子电池中的锂盐含量会下降。最后，F是LiPF6盐和有用的电解质添加剂（如氟乙烯碳酸酯和LiPO2F2）的组成部分。这些可以通过核磁共振在细胞老化过程中追踪。******达恩实验室是一个多元化和包容性的环境，大约有25名研究人员。超过33%的员工是女性，超过40%的员工是少数族裔。研究生和博士后来自世界各地，包括加拿大、美国、中国、突尼斯、埃及和爱沙尼亚。一名来自泰国的访问研究生将于2020年1月加入。**

The electrolyte of a lithium-ion cell is analogous to the blood in an animal. As the electrolyte degrades, the cell will begin to fail. Monitoring the composition of the electrolyte and the changes to the electrolyte during charge-discharge cycling of the cell allows one to learn about cell failure mechanisms and then correct them. This akin to blood tests used to diagnose illnesses and diseases in humans. Our laboratory heavily uses NMR spectroscopy to monitor changes in battery electrolyte. This is presently done at the Dalhousie NMR facility where large NMR spectrometers that use expensive and rare liquid helium and employed. ******This request is for a benchtop NMR spectrometer which uses a permanent magnet and therefore no liquid helium. Modern benchtop NMR spectrometers are simple and inexpensive to use, highly robust and can be powered from a 115V outlet. The time needed to collect a high quality spectrum is also extremely short, on the order of a few minutes. ******Our laboratory creates over 1000 Li-ion and “anode-free” pouch-type cells per month for a variety of tests. Many of these cells are subjected to NMR analysis of their electrolyte after testing, and an even larger fraction should be. The results of the experiments are highly valuable and the number of students in my lab using this technique is now six and is growing rapidly. Access to the Dalhousie NMR facility is proving to be insufficient and inconvenient. A benchtop NMR system will allow us to increase our productivity and hence increase our ability to create high energy density lithium batteries with longer lifetime. Our recent success has been highlighted in the media, for example: https://marker.medium.com/tesla-may-have-invented-a-million-mile-electric-car-battery-c3c11cc76d84 ******Benchtop NMR spectrometers can normally be set to be able to measure three nuclei and we will select H, Li and F. H is a component in all the non-aqueous solvents that are used in the electrolyte. Li is, of course, present in the electrolyte as the salt. We and others have shown that the Li salt content decreases in Li-ion cells under certain conditions during charge and discharge cycling. Finally, F is a component of the LiPF6 salt and of useful electrolyte additives such as fluoroethylene carbonate and LiPO2F2. These can be tracked during cell aging by NMR.******The Dahn lab is a diverse and inclusive environment of about 25 researchers. Over 33% of the personnel are female and over 40% are racially visible minorities. Graduate students and postdocs are from all over the world, including Canada, USA, China, Tunisia, Egypt and Estonia. A visiting graduate student from Thailand will join in January of 2020. **