Ni-P/NiOOH Heterointerface and Defect-Regulated ZIF-67-Derived Porous Nanosheet Electrodes for Photo-Assisted Supercapacitive Energy Storage

Abstract

Conventional supercapacitors are limited by incomplete active-site utilization and sluggish interfacial charge transfer. Photo-assisted energy storage offers a route to regulate these processes using photogenerated carriers. In this work, a self-supported CC@ZIF-67/Ni/P electrode was prepared by in situ growth of ZIF-67 on carbon cloth, followed by Ni incorporation and phosphorus-source regulation. The central design feature is a Ni-P/NiOOH heterointerface formed within an open porous nanosheet network. HRTEM and XPS provide local structural and surface-chemical evidence for this composite interface. The porous network improves electrolyte accessibility, and defect-related states may assist carrier trapping and migration; however, heterointerfacial coupling is proposed to play the principal role and may facilitate interfacial electron transfer and photogenerated-carrier separation. Under illumination, the electrode reaches an areal capacitance of 1868 mF·cm−2 at 10 mA·cm−2, together with a lower apparent interfacial resistance and a reproducible light-on/light-off transient response. The illuminated electrode retains 16.9% of its initial capacitance after 10,000 cycles, identifying long-term durability as a remaining limitation. These results support further investigation of interfacial coupling in MOF-derived photo-assisted electrodes.