Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
Wilton E. Scott Institute for Energy Innovation, Carnegie Mellon University, Pittsburgh, PA, 15213, USA.
Adv Sci (Weinh). 2023 Jun;10(16):e2300068. doi: 10.1002/advs.202300068. Epub 2023 Apr 17.
This study explores the relationships between material quench rate during processing and the resulting structural and electrochemical properties of Li[Ni Li Mn ]O . Samples of this lithium-rich material are prepared with highly contrasting postfiring cooling methods: a rapid water emersion quench or closed-door oven cooling. The contrasting approaches result in samples with different structural, chemical, and electrochemical behaviors; after cycling the rapidly quenched material yields greater capacity, greater stability, and initially lower, but more stable voltages than the slower cooled samples. Through the use of scanning tunneling electron microscopy, X-Ray Diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) it is demonstrated that rapidly quenched powders are more structurally uniform and chemically homogenous before cycling. By comparing these precycling sample to postcycling samples, it is then examined how this increased structural uniformity and chemical homogeneity leads to the superior electrochemical properties of the rapidly quenched samples.
这项研究探讨了加工过程中材料淬火速率与富锂材料 Li[Ni Li Mn ]O 的结构和电化学性能之间的关系。使用截然不同的后烧制冷却方法制备了这种富锂材料的样品：快速水浸淬火或闭门烤箱冷却。对比方法导致了具有不同结构、化学和电化学行为的样品；循环后，快速淬火材料的容量更大、稳定性更好，初始电压较低，但更稳定，而较慢冷却的样品则相反。通过使用扫描隧道电子显微镜、X 射线衍射（XRD）和 X 射线光电子能谱（XPS），证明了在循环之前，快速淬火粉末在结构上更加均匀，化学上更加均匀。通过将这些预循环样品与后循环样品进行比较，研究了这种结构均匀性和化学均匀性的提高如何导致快速淬火样品具有优越的电化学性能。
