Dual-ion storage in bipolar covalent organic frameworks with spatially separated redox centers enables high performance magnesium batteries

Rechargeable magnesium batteries (RMBs) are regarded as highly promising candidates for post-lithium-ion energy storage systems, owing to the abundance of magnesium resources and their intrinsically dendrite-free. However, their development has been significantly impeded by the scarcity of high-voltage cathode materials and the challenge of designing electrolytes with wide electrochemical stability windows. Herein, we report the rapid synthesis of two bipolar n-p type three-component covalent organic frameworks—TPT-COF and TNT-COF—via a microwave-assisted solid-phase method. These COFs enable synergistic anion and cation storage through spatially separated redox centers. When coupled with a newly developed chlorine-free magnesium electrolyte, Mg[B(tfe)(hfip) 3 ] 2 /DME, the constructed magnesium dual-ion batteries exhibit discharge voltage plateaus exceeding 3.0 V, substantially higher than those of most existing magnesium battery systems. Moreover, the system demonstrates remarkable rate capability (retaining 108 mAh g −1 at 5 A g −1 ) and cycling stability (79% capacity retention after 2000 cycles at 3 A g −1 ). This work demonstrates a coordinated electrode-electrolyte design strategy, offering an innovative pathway toward high-voltage, high-power multivalent metal battery systems.