New collaborative paper (lead: Gündoğ Yücesan) published in ACS Nano. We have developed a new nickel–vanadium phosphonate framework that combines redox-active metal centers with a chemically robust layered structure for aqueous energy storage. The material remains stable from pH 2 to 10, delivers up to about 300 F/g under slow-scan conditions, and retains its performance over more than 10,000 charge-discharge cycles in neutral and acidic electrolytes. Its sustainable water-based synthesis, broad pH tolerance, and exceptional cycling stability make it a promising platform for next-generation aqueous supercapacitors.