An Ultrahigh Performance Zinc‐Organic Battery using Poly(catechol) Cathode in Zn(TFSI)2‐Based Concentrated Aqueous Electrolytes

Abstract Aqueous zinc‐metal batteries (AZMBs) are predicted to be an attractive solutions for viable, high‐performance, and large‐scale energy storage applications, but their advancement is greatly hindered by the lack of adequate aqueous electrolytes and sustainable cathodes. Herein, an ultra‐robust Zn‐polymer AZMB is demonstrated using poly(catechol) redox copolymer (P(4VC 86 ‐ stat ‐SS 14 )) as the cathode and concentrated Zn(TFSI) 2 aqueous solution as stable electrolyte. The Zn(TFSI) 2 electrolyte shows enhanced ion‐transport properties and confers improved (electro)chemical compatibility with superior cell performance compared to traditional ZnSO 4 . The assembled Zn || P(4VC 86 ‐ stat ‐SS 14 ) (2.5 mg cm −2 polymer loading) cell simultaneously delivers remarkable capacities of 324 and 98 mAh g −1 at 1 and 450 C, respectively, and extremely high cyclability with only 0.00035% capacity fading rate/cycle over 48 000 cycles at 30 C. Interestingly, this battery can also operate at extremely low temperatures (−35 °C) still maintaining good capacity values (178 mAh g −1 ). Moreover, 352 Wh kg polymer −1 specific energy is attractive, while the high value of 72 Wh kg polymer −1 at unprecedented specific power of 150 kW kg polymer −1 is particularly intriguing. This overall performance is far superior to the state‐of‐the‐art AZMBs, making it a competitive choice for sustainable batteries without compromising performance.