Cross-linked polyaniline for production of long lifespan aqueous iron||organic batteries with electrochromic properties

• Published in: Nature communications Vol. 14; no. 1; p. 3117
• Main Authors: Lv, Haiming, Wei, Zhiquan, Han, Cuiping, Yang, Xiaolong, Tang, Zijie, Zhang, Yantu, Zhi, Chunyi, Li, Hongfei
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 30.05.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 147/135; 147/143; 639/301; 639/301/299; 639/301/299/891; 639/4077/4079; 639/638/403; Anions; Batteries; Crosslinking; Cycles; Electrochemistry; Electrochromism; Electrodes; Electrolytes; Energy storage; Humanities and Social Sciences; Hydrogels; Iron; Life span; Melamine; multidisciplinary; Polyanilines; Protons; Science; Science (multidisciplinary); Specific capacity; Stability
• ISSN: 2041-1723
• DOI: 10.1038/s41467-023-38890-y

Aqueous iron batteries are appealing candidates for large-scale energy storage due to their safety and low-cost aspects. However, the development of aqueous Fe batteries is hindered by their inadequate long-term cycling stability. Here, we propose the synthesis and application as positive electrode active material of cross-linked polyaniline (C-PANI). We use melamine as the crosslinker to improve the electronical conductivity and electrochemical stability of the C-PANI. Indeed, when the C-PANI is tested in combination with a Fe metal negative electrode and 1 M iron trifluoromethanesulfonate (Fe(TOF) 2 ) electrolyte solution, the coin cell can deliver a specific capacity of about 110 mAh g −1 and an average discharge voltage of 0.55 V after 39,000 cycles at 25 A g −1 with a test temperature of 28 °C ± 1 °C. Furthermore, mechanistic studies suggest that Fe 2+ ions are bonded to TOF − anions to form positively charged complexes Fe(TOF) + , which are stored with protons in the C-PANI electrode structures. Finally, we also demonstrate the use of C-PANI in combination with a polymeric hydrogel electrolyte to produce a flexible reflective electrochromic lab-scale iron battery prototype. Aqueous iron batteries are safe and cost-effective candidates for large-scale energy storage. However, their long-term cycling stability is inadequate. Here, the authors propose a crosslinked polyaniline-based positive electrode for high-power aqueous iron batteries with electrochromic properties.