Bipolar conjugated microporous polymer anchoring graphene hybrids for high-performance zinc–organic batteries

Abstract

Redox organic polymers have emerged as cathode candidates for zinc–organic batteries (ZOBs) due to their high electrochemical activity, environmental friendliness and structural designability. However, most organic polymers are confined to limited active sites and unstable structures, resulting in low capacity and poor cycling performance. Here, we propose an effective inorganic/organic anchoring strategy in which bipolar conjugated microporous polymers (CMPs) are anchored on the reduced graphene oxide (rGO) surface to form rGO@CMPs hybrids via π–π stacking and hydrogen bonding interactions. Based on the rGO@CMPs cathode, the assembled ZOBs can provide capacities up to 378 mA h g⁻¹ at 0.2 A g⁻¹, an impressively high energy density of 251 W h kg⁻¹ and a capacity retention of 90.1% after 25 000 cycles. The outstanding electrochemical performances of rGO@CMPs are rooted in the unique anchored structure guided by its novel molecular design. On the one hand, the well-designed molecular structure endows bipolar CMPs with high-density dual redox-active centers, which allow for alternate storage of Zn²⁺/CF₃SO₃⁻ ions to improve the capacity. On the other hand, the introduced rGO can firmly interact with CMPs to suppress their dissolution, resulting in fast reaction kinetics, excellent structural stability and high ion accessibility. This molecular design-guided inorganic/organic anchoring strategy provides a new approach for cathode construction and improves the high performance of ZOBs.