Rice Husk-Derived P-doped CNTs on Cu–ZnO/NPC as a Binder-Free electrodes for aqueous supercapacitors and oxygen evolution

[Display omitted] •The Rice Husk-Derived P-Doped CNTs in Cu–Zn–O/NPC nanomaterial is synthesized by the hydrothermal method and used as a battery-grade electrode for supercapattery devices.•An outstanding specific capacity of 1263C/g is obtained.•The remarkable high-energy density of 66Wh/kg at a power density of 800 W /kg is conceived.•Excellent cyclic stability of 98% capacity retention is obtained after 18,000 consecutive charge–discharge cycles are estimated. In the quest to bolster the electrochemical efficiency of metal oxide electrodes for high-performance hybrid supercapacitors, the integration of phosphorus doping emerges as a pivotal method. This study delves into the fabrication process of a specialized P-CNT on Cu–ZnO/NPC composite through a meticulous in-situ synthesis followed by phosphating. The strategic incorporation of phosphorus heteroatoms orchestrates a profound alteration in the electronic structure of the Cu–ZnO/NPC matrix, effectively augmenting its storage capabilites. The electrode showcases a commendable specific capacitance of 1619C/g. Making this innovation into a hybrid supercapacitor configuration (P-CNT@Cu–ZnO/NPC //activated carbon) yields an impressive energy density of 56.13 Wh/kg at 1250 W/kg. Even after enduring 10,000 exhaustive testing cycles, the device remarkably retains 98.0 % of its initial capacitance, affirming the resilience and enduring performance of this tailored design. In oxygen evolution reaction (OER) application, the P-CNT@Cu–ZnO/NPC electrode demonstrated 43.26 mV/dec tafel slope. These groundbreaking findings underscore the transformative potential of the P-CNT@Cu–ZnO/NPC composite in shaping the landscape of future energy storage electrode materials.