Date of Award
Master of Science (MS)
As sodium batteries hold great promise as a next-generation energy storage device to replace lithium batteries, the development of sodium battery materials has become increasingly urgent. The current study aims to investigate two potential sodium-ion battery cathode materials, Sodium Vanadium Phosphate, and Sodium Manganese Hexacyanoferrate, optimize the experimental procedures, conduct a systematic analysis of material properties and characterization, and ultimately determine the ideal synthesis conditions for these materials.
In the first part of the study, we focused on optimizing the synthesis of Sodium Vanadium Phosphate. By investigating various synthesis conditions, such as annealing temperature, pressure, ascorbic acid content, and material addition order, the study identified the optimal parameters for achieving high capacity and cyclic stability. We also found the key phenomenon that indicates the high performance of materials. The highest capacity of NVP could reach 96mAh/g at 1C.
In the second part of the study, we investigated two synthesis methods: one with a chelating agent and the other without. For the chelation-free method, we optimized ethanol content, aging time, and washing reagents and achieved the highest capacity of 112 mAh/g at 1C with an ethanol ratio of 1:3, an aging time of 12 hours, and deionized water as the washing solvent. In the chelating agent method, we used tetra-sodium EDTA as the chelating agent and added ascorbic acid as a dissociating agent. This method resulted in a material with a good dispersion system and achieved a capacity of 130 mAh/g at 1C. For future PBA synthesis, we plan to optimize based on this method and expand it to KPBA synthesis as much as possible.
Xianglin Li; Sanghoon Bae