In the current work, aluminum dross from the aluminum industry and fired-clay brick waste (Homra) were combined with alkaline activators (Na₂SiO₃/NaOH) with varying molarities of NaOH to create insulating geopolymer bricks. An alkaline activator with an (S/L) ratio of 3/1 was combined with Homra to replace it partly. The mixture was then molded into 50 × 50 × 50 mm³ stainless steel molds. Water absorption, compressive strength, bulk density, and apparent porosity of the produced geopolymer were measured at various curing durations and NaOH molarities. The findings showed that adding more aluminum dross waste replacement leads to a decrease in bulk density and compressive strength and an increase in the creation of pores that improve the produced bricks’ ability to insulate against heat. Using 8 M of NaOH after 28 days, the findings revealed that 3% aluminum dross waste replacement has a compressive strength of about 8.6 MPa, water absorption of 14.6%, bulk density of 1.307 g/cm³, and thermal conductivity of 0.32 W/m·K. The Egyptian standard, ASTM C62, satisfies these outcomes. Using DesignBuilder energy simulation software version 6.1.06, the constructed insulating brick under ideal circumstances was utilized to calculate its contribution performance in energy consumption. The annual energy consumption was reduced by about 21% compared to traditional hollow cement bricks.

The development of advanced hybrid supercapacitors (Hy-SCs) demands electrode materials that combine high redox activity with high porosity to achieve both high energy and power densities. In this work, we synthesized hollow microfibrous nickel cobalt oxide (NiCo₂O₄) via a facile sol-gel approach with the medical fibrous cloth as a disposable template, yielding an interconnected porous network with enhanced surface area and ion-accessible channels. The physicochemical analyses confirmed the formation of a hierarchical hollow microstructure, favoring efficient electrolyte penetration and rapid ion diffusion. The electrochemical properties of microfibrous NiCo₂O₄ demonstrated a battery-type redox behavior with a maximum specific capacitance of 648.5 F g⁻¹ (383.9 C g⁻¹) at 1 A g⁻¹, with excellent rate capability, retaining 64% capacitance at a high current density of 15 A g⁻¹. When coupled with activated carbon in a two-electrode device, the Hy-SC exhibited a broad voltage window of 1.6 V, delivering an energy density of 21.15 Wh kg⁻¹ and a high-power density of 2750 W kg^–1. Moreover, the device sustained 90.9% capacitance retention after 10,000 cycles, highlighting outstanding long-term stability. Utilizing the high energy storage properties, the viability of Hy-SC was validated by powering multiple LEDs for several minutes, underscoring the capability of the device for real-world portable electronics. The scalable and low-cost fabrication route offers a viable pathway for designing hollow, fibrous, redox-type materials for high-performance energy storage systems. Graphical abstract