fig4

Figure 4. Naphthalene diimides (NDI) based derivatives and the performance for AORFBs^[44,46]. (A) Synthesis of [M₂-BNDI] (M = K or Na); (B) CV curves of 5 mM [K₂-BNDI] in 1 M KCl for 500 cycles at 20 mV s^-1 (left) and at scan rates from 5 to 640 mV s^-1 (right); (C) Galvanostatic cycling profiles. Current density: 5-20 mA cm^-2; (D) Capacity retention and CE profiles for 200 cycles; (E) ESI-MS analysis with the positive ionization mode of [Na₂-BNDI] anolyte after 200 cycles (top). The as-prepared [Na₂-BNDI] (middle) and 4-OH-TEMPO (bottom) are presented for comparison; (F) An AORFB with 50 mM 2H-NDI and BTMAP-Fc in 0.5 M NH₄Phos and 1 M NH₄Cl; (G) Rate performance. Current density: 5-60 mA cm^-2. (H) Stability behavior. Reproduced with permission^[46]. Copyright 2020, Royal Society of Chemistry.