Bipolar Organic Electrodes for Energy Storage: A Review of Structural Design, Electrolyte Adaptation, and Future Perspectives

Bipolar organic electrodes integrate p-type and n-type redox centers within a single molecular architecture, offering a route to couple the high operating potentials of p-type chemistry with the high capacities associated with n-type reactions. Realizing this advantage requires more than the incorporation of complementary redox sites, because cation- and anion-coupled reactions are strongly influenced by the surrounding electrolyte environment. This review examines bipolar organic electrodes by linking their charge-storage chemistry to two closely coupled aspects: structural design and electrolyte adaptation. The discussion covers small molecules, conjugated polymers, donor–acceptor architectures, and porous organic frameworks, with attention to how molecular and framework structures determine redox-site utilization, electronic transport, and structural stability. Electrolyte effects are then considered in terms of salt and solvent selection, solvation behavior, dissolution, ion-transfer kinetics, and electrode–electrolyte interfacial chemistry. On this basis, structure-specific electrolyte matching and integrated electrode/electrolyte codesign are identified as key directions for translating the tunable redox chemistry of bipolar organic electrodes into practical energy-storage systems.