Rational construction of self-standing sulfur-doped Fe2O3 anodes with promoted energy storage capability for wearable aqueous rechargeable NiCo-Fe batteries

• Main Authors: Yang, Jiao, Zhang, Qichong, Wang, Zhixun, Wang, Zhe, Kang, Lixing, Qi, Miao, Chen, Mengxiao, Liu, Wen, Gong, Wenbin, Lu, Weibang, Shum, Perry Ping, Wei, Lei
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Electrical and electronic engineering; Aqueous Electrolytes; Fiber Electronics
• Online Access: https://hdl.handle.net/10356/155257
• Institution: Nanyang Technological University

Aqueous rechargeable Ni-Fe batteries featuring an ultra-flat discharge plateau, low cost, and outstanding safety characteristics show promising prospects for application in wearable energy storage. In particular, fiber-shaped Ni-Fe batteries will enable textile-based energy supply for wearable electronics. However, the development of fiber-shaped Ni-Fe batteries is currently challenged by the performance of fibrous Fe-based anode materials. In this context, this study describes the fabrication of sulfur-doped Fe2O3 nanowire arrays (S-Fe2O3 NWAs) grown on carbon nanotube fibers (CNTFs) as an innovative anode material (S-Fe2O3 NWAs/CNTF). Encouragingly, first-principle calculations reveal that S-doping in Fe2O3 can dramatically reduce the band gap from 2.34 to 1.18 eV and thus enhance electronic conductivity. The novel developed S-Fe2O3 NWAs/CNTF electrode is further demonstrated to deliver a very high capacity of 0.81 mAh cm−2 at 4 mA cm−2. This value is almost sixfold higher than that of the pristine Fe2O3 NWAs/CNTF electrode. When a cathode containing zinc-nickel-cobalt oxide (ZNCO)@Ni(OH)2 NWAs heterostructures is used, 0.46 mAh cm−2 capacity and 67.32 mWh cm−3 energy density are obtained for quasi-solid-state fiber-shaped NiCo-Fe batteries, which outperform most state-of-the-art fiber-shaped aqueous rechargeable batteries. These findings offer an innovative and feasible route to design high-performance Fe-based anodes and may inspire new development for the next-generation wearable Ni-Fe batteries.