Porous Fe₂O₃ Modified by Nitrogen-Doped Carbon Quantum Dots/Reduced Graphene Oxide Composite Aerogel as a High-Capacity and High-Rate Anode Material for Alkaline Aqueous Batteries
2019
Yun, Xiaoru | Li, Jingying | Chen, Xianhong | Chen, Han | Xiao, Li | Xiang, Kaixiong | Chen, Wenhao | Liao, Haiyang | Zhu, Yirong
Carbon quantum dots (CQDs) as novel types of emerging materials have aroused tremendous attention in recent years. Herein, we report for the first time a new application of 3D CQD-based composite aerogels as excellent electrode materials for alkaline aqueous batteries. The scalable graphitic CQDs are prepared with high yields (>40%) and further utilized to fabricate the novel nitrogen-doped CQDs/reduced graphene oxide/porous Fe₂O₃ (N-CQDs/rGO/Fe₂O₃) composite aerogels with different contents of Fe₂O₃. Benefiting from the unique 3D network composite aerogel structure with a high surface area and hierarchical porous structure as well as the synergistic effect of high-capacity Fe₂O₃ and highly conductive and stable N-CQDs/rGO, the composite aerogels achieve enhanced electrochemical properties with ultrahigh specific capacity, admirable rate property, and superior cycling performance. Furthermore, the N-CQDs/rGO/Fe₂O₃-1 electrode (Fe₂O₃, 34.9 wt %) exhibits the best rate capability (72.1, 58.9, and 46.2% capacity retention at 5, 50, and 100 A g–¹, respectively) and cycle performance (80.4% capacity retention at 3 A g–¹ over 5000 cycles), while the N-CQDs/rGO/Fe₂O₃-3 electrode (Fe₂O₃, 62.3 wt %) displays the highest specific capacity (274.1 mA h g–¹ at 1 A g–¹). The current research provides a valuable guidance for developing high-performance 3D CQD-based composite aerogels for application in energy storage systems.
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