Abstract
Aqueous sulfur batteries are promising for high-performance and low-cost energy storage. However, their energy density is limited by low battery voltages due to the negative potential [E0 = −0.51 V vs standard hydrogen electrode (SHE)] of low valent sulfur redox (S0/S2-) and low discharge capacity (∼300 mA h g-1) of high valent sulfur redox (S2O32-/S4O62- or S4+/S0). Herein, we develop a reversible alkaline sulfur cathode via introducing Cu2+ and Zn2+ ion mediators, exhibiting a redox potential above 0 V vs SHE, which is higher than low valent sulfur redox and high specific capacity of 1340 mA h g-1. Furthermore, the proposed rechargeable alkaline sulfur batteries achieve a high operating battery voltage of approximately 1.1 V and rapid reaction kinetics, sustained even at high current densities of up to 10 A g-1. In-depth characterization and DFT calculations reveal that the alkaline sulfur electrochemistry follows a six-electron conversion reaction S ↔ CuS ↔ ZnS + Cu2O ↔ Cu, delivering an energy density of 1168 W h kg-1 and a power density of 8110 W kg-1. This work offers insights into aqueous sulfur electrochemistry and shows an alternative to achieving high energy density aqueous batteries.
Original language | English |
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Journal | ACS Nano |
DOIs | |
Publication status | Accepted/In press - 2025 |
Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2025 American Chemical Society.
ASJC Scopus Subject Areas
- General Materials Science
- General Engineering
- General Physics and Astronomy
Keywords
- aqueous batteries
- aqueous sulfur batteries
- high redox potential
- rapid kinetics
- sulfur electrochemistry