Imaging dendrite growth in solid-state sodium batteries using fluorescence tomography technology.

Yang, Shuaishuai; Li, Na; Zhao, Enyue; Wang, Chengzhi; He, Jingxin; Xiao, Xiong; Fang, Debao; Ni, Qing et al. · Sci Adv · 2024

basic_science · Level V

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Abstract

Dendrite growth in solid-state sodium batteries (SSBs) is one of the most concerned issues that critically affect the battery efficiency and cycling performance. Here, by designing a fluorescent Eu<sup>3+</sup>-doped Na<sub>3</sub>Zr<sub>2</sub>Si<sub>2</sub>PO<sub>12</sub> solid electrolyte (SE) to facilitate three-dimensional (3D) optical imaging on a confocal laser scanning microscopy, a fluorescence tomography (FT) method is developed for observing the sodium dendrite growth during charge/discharge cycles of the SSBs in a 3D view. It is quantitatively revealed that small-size sodium islands appear after several cycles, and with the cycles increasing, large-size dendrites in tens of micrometers gradually form until a critical sodium dendrite volume arrives where a short circuit or severe performance deterioration occurs. Furthermore, by regulating the Eu<sup>3+</sup> doping ratio, a record-high sodium plating/stripping cycling stability for more than 1 year (487.5 days) is achieved at 25°C. This work demonstrates an FT method observing sodium dendrite growth in SSBs and will promote the functional design of high-performance SEs.