Revealing the Inside of a Nanoscale Na-ion Battery: New Understanding on Sodium Intercalation in Cathodes

这笔赠款的研究目的是促进对电极中钠离子反应和钠离子电池中化学诱导的失效和断裂的潜在机制的了解。为此，将在透射电子显微镜内对阴极电极进行电化学探测，在那里可以同时高分辨率地监测电极的微观结构。室温可充电钠离子电池由于成本较低和钠资源的广泛可获得性而具有与锂离子电池竞争的能力。虽然全世界对锂离子电池的大量研究都集中在那里，但与室温可充电钠离子电池相关的科学挑战相对来说还没有被探索过。考虑到锂资源非常有限，而且价格在过去20年里不断上涨，这一点至关重要。钠离子电池面临的挑战比锂离子要复杂得多，因为钠离子比锂离子大70%，这会在将钠离子驱动到主电极上时产生巨大的机械应力。钠离子进入电极会引发复杂的化学反应和故障，但人们对此知之甚少，电池寿命大大缩短。钠离子电池广泛使用的一个重要挑战是在使用条件下循环稳定性很低。通过这笔赠款，PI将研究新正极材料方面几个尚未解决的科学挑战，如果成功解决，这些挑战可能会使长期耐用的可充电钠离子电池技术商业化。提出了几个将研究与本科教育和外联活动相结合的场所。通过对电池主题的简单介绍，接受本科教育的女性和少数民族学生将接触到这一研究项目。还计划为当地高中女生和代表性不足的学生开展其他外展活动。显微镜实验的实时视频将被制作出来，并通过YouTube和选定的科学网络提供给社区。

The research objective of this grant is to advance the understanding of the underlying mechanisms that are active in Na-ion reactions in electrodes and chemically-induced failure and fracture in Na-ion batteries. For this purpose, the cathode electrode will be subjected to electrochemical probing inside a transmission electron microscope (TEM) where the microstructure of electrodes can be simultaneously monitored in high resolution. Room-temperature rechargeable Na-ion batteries can be competitive to Li-ion batteries due to their lower cost and the widespread availability of the sodium resources. While tremendous research is focused on Li-ion batteries worldwide, scientific challenges associated with room-temperature rechargeable sodium-ion batteries have been relatively unexplored. This is of prime importance considering that Li resources are very limited and their price has increased continuously during the past 20 years. The challenges of Na-ion batteries are much more complicated than the Li-ion case, as Na-ions are larger than Li-ions by 70 percent, which induces large mechanical stresses upon driving the Na-ions into the host electrode. The entry of sodium into the electrodes triggers complicated chemical reactions and failures that are poorly understood, and the battery life is reduced drastically.An important challenge in the broad use of Na-ion batteries is the very low cycling stability in service conditions. Through this grant, the PI will investigate several unresolved scientific challenges in new cathode materials which, if successfully resolved, could enable the commercialization of long lasting rechargeable Na-ion battery technologies. Several venues for integrating research with undergraduate education and outreach activities are proposed. Female and minority students for undergraduate education will be exposed to this research project through simple introductions to the battery subject. Other outreach activities are also planned for local high school female and underrepresented students. Real time videos of microscopy experiments will be produced and made available to the community via YouTube© and selected scientific networks.