Seaweed-Derived Carbon Aerogel for Supercapacitors Holds 87% Capacity After 50,000 Cycles

Researchers at the Indian Institute of Petroleum and Energy turned agar-agar, a gelling agent from red seaweed, into a nitrogen-doped carbon aerogel for supercapacitors. The material has a surface area of about 2420.5 square meters per gram and delivered 153 farads per gram in a neutral sodium sulfate electrolyte. The symmetric device reached 35.8 watt-hours per kilogram and 23.18 kilowatts per kilogram, running at a 1.3 volt cell window. After 50,000 charge-discharge cycles, the supercapacitor retained roughly 87 percent of its initial capacitance with near 100 percent coulombic efficiency. The team used ammonium chloride for pore formation and nitrogen doping, then potassium hydroxide activation to build a hierarchical pore network. Results were published in the journal Ionics, and the work points to a low-cost, renewable route to long-life storage for power quality, regenerative braking, and intermittent renewable buffering.