Molecularly Anchored n-Type Quinone/Graphene Heterostructures Enabling High-Capacity and Ultra-stable Proton Storage

Quinone-based organic electrodes are attractive for aqueous proton batteries owing to their fast and reversible proton-coupled redox chemistry. However, their practical application is largely restricted by severe dissolution in acidic electrolytes, poor structural stability, and low electronic conductivity. Herein, we report a molecularly anchored n-type quinone/graphene heterostructure constructed by integrating tetraaminobenzoquinone (TABq) with reduced graphene oxide (rGO) through a facile solvothermal strategy. Strong π-π stacking, hydrogen-bonding interactions, and covalent linkages effectively immobilize TABq molecules on the conductive rGO framework, thereby suppressing active-material dissolution, enhancing electrode integrity, and constructing efficient electron/proton transport pathways. The open heterointerface and abundant redox-active sites further promote rapid proton uptake/release and accelerate charge-transfer kinetics. Benefiting from this rational heterostructure design, the optimized TABq/rGO electrode delivers a high specific capacity of 349.78 mAh g-1 at 1 A g-1, remarkable rate capability of 131.12 mAh g-1 even at 100 A g-1, and excellent cycling durability. When coupled with a 3,4,9,10-perylenetetracarboxylic dianhydride anode, the full cell achieves a reversible capacity of 129.03 mAh g-1 at 0.75 A g-1 and maintains 75.43% of its capacity after 1000 cycles. Moreover, TABq/rGO-based symmetric proton battery exhibits outstanding long-term stability, retaining 74.17% of its capacity after 10,000 cycles. Experimental characterizations combined with density functional theory calculations reveal that the TABq/rGO heterointerface regulates charge distribution, stabilizes the quinone redox centers, and lowers the kinetic barrier for proton storage. This work highlights an effective molecular anchoring strategy for developing high-capacity, high-rate, and durable organic electrodes for advanced aqueous proton batteries.