ABSTRACT Organic small molecule electrodes with high‐density redox sites are receiving attention for building high‐capacity all‐organic aqueous batteries. However, their poor charge transfer and high solubility stand as pivotal barriers for the full utilization of redox‐active groups and the liberation of high theoretical capacity. Here we design a new‐type nitroaromatic@MXene heterostructure by grafting four‐electron‐receptor 1,3,6,8‐tetranitropyrene (TNP) molecule onto MXene scaffolds to construct a hybrid electrode (TNP@MXene) integrated with high activity, conductivity and structural stability. Four redox‐active nitro motifs of TNP in TNP@MXene as H‐bond acceptors are exclusively coordinated with flexible NH 4 + charge carriers (H‐bond donators) with lower activation energy (0.34 vs 0.48 eV for sole TNP molecule). Meanwhile, the highly conductive MXene provides continuous charge delocalization paths and strengthens anti‐dissolution ability of TNP in aqueous electrolytes, enabling adequate exposure of nitro sites. Consequently, a two‐step octa‐H‐bonded heterointerfacial NH 4 + coordination mechanism is rationalized for TNP@MXene heterostructure electrode, affording an impressive capacity (342 mAh g −1 ). As a proof‐of‐concept, TNP@MXene as a cathode are further highlighted in aqueous NH 4 + ‐ion battery, liberating superior energy density (182.3 Wh kg −1 cathode ) and excellent lifespan (60 000 cycles). These findings constitute a major advancement of multielectron organic heterostructure materials as hybrid electrodes for advanced aqueous batteries.
Huang et al. (Thu,) studied this question.