Porous Zn Nano-Wafer Aerogels for Asymmetric Supercapacitors: Synthesis, Structural Engineering, and Performance

Transition metal oxide aerogels (AGLs) have attracted considerable attention in recent years due to their exceptional properties, including high surface area, significant porosity, and ultralow density. In this study, we report the first-time synthesis of zinc oxide nano-wafers and zinc aerogels for application as supercapacitor electrodes. The aerogels were synthesized via a novel one-pot hydrolysis method using NaBH4 as a reducing agent and subsequently annealed at 200 °C (ZnAGL(200)) and 450 °C (ZnAGL(450)) to investigate the influence of temperature on their electrochemical properties. Structural and morphological characterizations were conducted using XRD, FTIR, BET, XPS, SEM, and TEM analyses. Among the fabricated electrodes, the aerogel annealed at 200 °C (ZnAGL(200)) exhibited superior energy storage performance, attributed to its amorphous, continuous network structure, which enhanced its surface area and reduced its density compared to both the as-synthesized (ZnAGL(RT)) and 450 °C-annealed (ZnAGL(450)) counterparts. A two-electrode device demonstrated excellent cycling stability over 10,000 cycles, achieving an energy density of 7.97 Wh/kg and a power density of 15 kW/kg. These findings highlight the potential of zinc aerogels as materials for next-generation lightweight energy storage systems, with promising applications in industrial, mechanical, and aerospace technologies.