Radiation-assisted heterostructure engineering in 2D conductive metal–organic framework significantly boosts electrochemical performance for supercapacitor

Heterostructure engineering was applied for the first time in two-dimensional conductive metal–organic frameworks (2D c-MOFs) to enhance their electrochemical performance, which is of great significance for the exploration of promising electrode materials for high-performance supercapacitors. Specifically, a novel 2D c-MOF-based heterostructure (copper catecholate (Cu-CAT)@Cu₂O) was in situ constructed through gamma-ray radiation-induced one-pot way under ambient conditions. The existence of Cu₂O in Cu-CAT was confirmed by diverse spectroscopic techniques and high-resolution electron microscopy images. Additionally, the constructed heterostructure significantly improved electrochemical performance, as demonstrated by experimental and theoretical analyses. Notably, Cu-CAT@Cu₂O exhibited an impressive gravimetric capacitance of 761 F·g⁻¹, nearly 3 times that of solvothermally synthesized Cu-CAT (262 F·g⁻¹), along with superior rate capability, faster charge–discharge kinetics, and excellent cycling stability. Furthermore, a symmetric two-electrode flexible supercapacitor device fabricated with Cu-CAT@Cu₂O achieved a high specific capacitance of 417 F·g⁻¹, a remarkable energy density of 98.5 Wh·kg⁻¹, and a better retention of 94.5% of its initial capacitance after 10,000 cycles. These findings highlight the potential of radiation-assisted heterostructure engineering as a versatile strategy for developing advanced MOF-based supercapacitors.