Synergistic complex modification and interface engineering in porous Ni(OH)₂-Ni₀.₈₅Se heterogeneous nanosheet composites for enhanced electrochemistry performance of RPP foam

Transition metal selenides (TMSes) are promising electrode materials for supercapacitors but suffer from poor conductivity and structural stability, restricting their electrochemical performance. Herein, we report a synergistic complex modification and interface engineering strategy to construct porous Ni(OH)₂-Ni₀.₈₅Se heterogeneous nanosheets anchored on elastic rGO-PEDOT:PSS (RPP) foam (RPP@Ni(OH)₂-Ni₀.₈₅Se) for high-performance electrochemical electrodes. The heterogeneous interface between Ni(OH)₂ and Ni₀.₈₅Se optimizes electronic structure, accelerates charge transfer, and relieves volume expansion. Meanwhile, the hierarchically porous RPP substrate provides rapid ion diffusion pathways and robust structural support for the composite electrode. Electrochemical tests demonstrate that the assembled device delivers a high specific capacitance of 143 F g −1 at 1 A g −1 , with a retains 58.2% capacitance after 5000 cycles. It also has a relatively high power density (375.1 W kg −1 ) and energy density (44.7 Wh kg −1 ). Theoretical calculations reveal that the built-in interfacial electric field effectively reduces the redox reaction energy barrier and improves electrochemical activity of the electrode. This work clarifies the structure-activity relationship between heterogeneous interface engineering and electrochemical performance, and provides a universal strategy for designing high-stability, high-activity transition metal selenide composite electrodes.