Volume 63, Issue 12 e202318369
Research Article

Hygroscopic Solutes Enable Non-van der Waals Electrolytes for Fire-Tolerant Dual-Air Batteries

Dr. Huarong Xia

Dr. Huarong Xia

Innovative Center for Flexible Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore

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Dr. Shengkai Cao

Dr. Shengkai Cao

Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, 138634 Singapore, Singapore

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Dr. Zhisheng Lv

Dr. Zhisheng Lv

Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, 138634 Singapore, Singapore

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Dr. Jiaqi Wei

Dr. Jiaqi Wei

Innovative Center for Flexible Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore

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Song Yuan

Song Yuan

Innovative Center for Flexible Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore

Institute of Flexible Electronics Technology of THU, Tsinghua University, 314000 Jiaxing, Zhejiang, China

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Prof. Xue Feng

Prof. Xue Feng

Center for Flexible Electronics Technology, Tsinghua University, No. 30, Shuangqing Road, 100084 Beijing, China

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Prof. Xiaodong Chen

Corresponding Author

Prof. Xiaodong Chen

Innovative Center for Flexible Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore

Institute for Digital Analytics and Science (IDMxS), Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore, Singapore

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First published: 05 January 2024
Citations: 1

Graphical Abstract

While the irreversible thermal transformation of electrolytes is typically attributed to solvent boiling, which disrupts solvent intermolecular interactions, our research revealed that hygroscopic solutes shift the determining factor to solute decomposition, breaking solute intramolecular bonds. As intramolecular bonds are much stronger, it enables ultrahigh thermal tolerance of non-van der Waals solute-in-air electrolytes.

Abstract

Thermal safety issues of batteries have hindered their large-scale applications. Nonflammable electrolytes improved safety but solvent evaporation above 100 °C limited thermal tolerance, lacking reliability. Herein, fire-tolerant metal-air batteries were realized by introducing solute-in-air electrolytes whose hygroscopic solutes could spontaneously reabsorb the evaporated water solvent. Using Zn/CaCl2-in-air/carbon batteries as a proof-of-concept, they failed upon burning at 631.8 °C but self-recovered then by reabsorbing water from the air at room temperature. Different from conventional aqueous electrolytes whose irreversible thermal transformation is determined by the boiling points of solvents, solute-in-air electrolytes make this transformation determined by the much higher decomposition temperature of solutes. It was found that stronger intramolecular bonds instead of intermolecular (van der Waals) interactions were strongly correlated to ultra-high tolerance temperatures of our solute-in-air electrolytes, inspiring a concept of non-van der Waals electrolytes. Our study would improve the understanding of the thermal properties of electrolytes, guide the design of solute-in-air electrolytes, and enhance battery safety.

Conflict of interests

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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