Sodium Penetration in Nasicon Solid Electrolytes Under High Current
Meeting abstracts(2023)
摘要
High conductivity solid electrolytes, such as NaSICON, are poised to play an increasingly important role in safe, reliable battery-based energy storage, enabling a new class of sodium-based batteries. Coupled demands of high current densities (≥0.1 A cm -2 ) and low temperature (<200 °C) operation, combined with increased discharge times for long duration storage (>12 h), challenge the limitations of solid electrolytes. Here, we explore the penetration of sodium into NaSICON at 0.1 A cm -2 in a symmetric molten sodium cell. Previous studies of β’’-alumina proposed that Poiseuille pressure-driven cracking (Mode I) and low levels of electronic conductivity leading to ion-electron recombination (Mode II) can cause metal accumulation within solid electrolytes, but a comprehensive study at high current density is necessary. To understand and differentiate these modes in NaSICON, this work employs unidirectional galvanostatic testing of Na|NaSICON|Na symmetric cells at 0.1 A cm -2 over 23 1-hour intervals at 110 °C. While galvanostatic testing shows a relatively constant, yet increasingly noisy voltage profile, electrochemical impedance spectroscopy (EIS) between intervals reveals a significant decrease in cell impedance which can be correlated with sodium metal penetration, as observed in scanning electron microscopy (SEM). Significant sodium accumulation from the stripping-side electrode suggests that Mode II failure may be far more prevalent than previously considered. Further, these findings suggest that total charge transported per unit area (mAh cm -2 ), an important parameter for long duration storage, may be a more critical parameter than current density (mA cm -2 ) when examining solid electrolyte failure. Together, these results provide a better understanding of the limitations of NaSICON solid electrolytes under high current density and can guide the design of coatings to improve electrode-electrolyte interfaces.
更多查看译文
关键词
nasicon solid electrolytes,sodium penetration
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要