Yu, CuipingSun, JianjianXia, ChenhongWang, YanZhang, JianfangCai, RuiCui, JiewuTan, HoeZhang, YongWu, Yucheng2024-08-152024-08-150021-9797https://hdl.handle.net/1885/733714638Coupling TiO2 within N-doped porous carbon (NPC) is essential for enhancing its Na+ storage performance. However, the role of different N configurations in NPC in improving the electrochemical performance of TiO2 is currently unknown. In this study, melamine is deliberately incorporated as a pore-forming agent in the self-assembly process of metal organic framework precursors (NH2-MIL-125(Ti)). This intentional inclusion of melamine leads to the one-pot and in-situ formation of highly active edge-N, which is vital for the development of TiO2/NPC with exceptional reactivity. Electrochemical performance characterization and density functional theory (DFT) calculation indicate that the interaction between TiO2 and pyridinic-N enriched NPC can effectively narrow the bandgap of TiO2/NPC, thereby significantly improving electron/ion transfer. Additionally, the abundant mesoporous channels, high N content and oxygen vacancies also contribute to the fast reaction kinetics of TiO2/NPC. As a result, the optimized TiO2/NPC-M, with high proportion of pyridinic-N (44.1 %) and abundant mesoporous channels (97.8 %), delivers high specific capacity of 282.1 mA h−1 at 0.05 A g−1, superior rate capability of 177.3 mA h−1 at 10 A g−1, and prominent capacity retention of 89.3 % over 5000 cycles even under ultrahigh 10 A g−1. Furthermore, the TiO2/NPC-M//AC sodium ion capacitors (SIC) device achieves a high energy density of 136.7 Wh kg−1 at 200 W kg−1. This research not only offers fresh perspectives on the production of high-performance TiO2-based anodes, but also paves the way for customizing other active materials for energy storage and beyond.We would like to extend our heartfelt gratitude for the invaluable support provided by the National Natural Science Foundation of China (52172293, 52072106, 52272195, 52202226), the Key R&D Projects of Anhui Province (202104b11020016), the Natural Science Foundation of Anhui Province (2308085ME143, 2108085QB66), and the China Postdoctoral Science Foundation (2021M701028). Furthermore, we are immensely grateful for the financial assistance received from the Fundamental Research Funds for the Central Universities (PA2023GDSK0079), the University Synergy Innovation Program of Anhui Province (GXXT-2022-016) and the 111 Project (B18018).application/pdfen-AU© 2024 Elsevier Inc.Sodium ion capacitorsTiO2Pyridinic-NCharge transferRate capability202410.1016/j.jcis.2024.01.0802024-05-12