Tellurium with Reversible Six-Electron Transfer Chemistry for High-Performance Zinc Batteries

• Published in: Journal of the American Chemical Society 2023-09, Vol.145 (37), p.20521-20529
• Main Authors: Chen, Ze, Wang, Shengnan, Wei, Zhiquan, Wang, Yiqiao, Wu, Zhuoxi, Hou, Yue, Zhu, Jiaxiong, Wang, Yanbo, Liang, Guojin, Huang, Zhaodong, Chen, Ao, Wang, Donghong, Zhi, Chunyi
• Format: Article
• Language: English
• Subjects: batteries; electric potential difference; electrolytes; energy density; ionic liquids; Lewis bases; tellurium; zinc
• ISSN: 0002-7863; 1520-5126; 1520-5126
• DOI: 10.1021/jacs.3c06488

Chalcogens, especially tellurium (Te), as conversion-type cathodes possess promising prospects for zinc batteries (ZBs) with potential rich valence supply and high energy density. However, the conversion reaction of Te is normally restricted to the Te2–/Te0 redox with a low voltage plateau at ∼0.59 V (vs Zn2+/Zn) rather than the expected positive valence conversion of Te0 to Te n+, inhibiting the development of Te-based batteries toward high output voltage and energy density. Herein, the desired reversible Te2–/Te0/Te2+/Te4+ redox behavior with up to six-electron transfer was successfully activated by employing a highly concentrated Cl–-containing electrolyte (Cl– as strong nucleophile) for the first time. Three flat discharge plateaus located at 1.24, 0.77, and 0.51 V, respectively, are attained with a total capacity of 802.7 mAh g–1. Furthermore, to improve the stability of Te n+ products and enhance the cycling stability, a modified ionic liquid (IL)-based electrolyte was fabricated, leading to a high-performance Zn∥Te battery with high areal capacity (7.13 mAh cm–2), high energy density (542 Wh kgTe –1 or 227 Wh Lcathdoe+anode –1), excellent cycling performance, and a low self-discharge rate based on 400 mAh-level pouch cell. The results enhance the understanding of tellurium chemistry in batteries, substantially promising a remarkable route for advanced ZBs.