the battery electrolyte to diffuse. The researchers pyrolized the aerogel to 1,000 degrees Celsius, turning the foam into a graphitic network, with many catalytic graphene edges. The aniline doped the foam with nitrogen, which enhances reduction. Phytic acid infuses the foam with phosphorus, helping oxygen evolution. The foam has a surface area of ∼1,663 m2/gr. Primary batteries demonstrated an open-circuit potential of 1.48 V, a specific capacity of 735 mAh/gr (Zn) (energy density of 835 Wh/kg (Zn)), a peak power density of 55 mW/cm³ and stable operation for 240 h after mechanical recharging. Two-electrode rechargeable batteries cycled stably for 180 cycles at 2 mA/cm3. Applications Vehicle propulsion Metallic zinc could be used as an alternative fuel for vehicles, either in a zinc–air battery or to generate hydrogen near the point of use. Zinc's characteristics have motivated considerable interest as an energy source for electric vehicles. Gulf General Atomic demonstrated a 20 kW vehicle battery. General Motors conducted tests in the 1970s. Neither project led to a commercial product. In addition to liquid, pellets could be formed that are small enough to pump. Fuel cells using pellets would be able to quickly replace zinc-oxide with fresh zinc metal. The spent material can be recycled. The zinc–air cell is a primary cell (non-rechargeable); recycling is required to reclaim the zinc; much more energy is required to reclaim the zinc than is usable in a vehicle. One advantage of utilizing zinc–air batteries for vehicle propulsion is the mineral's relative abundance when compared to lithium. As of 2020, the total global zinc reserves are estimated to be around 1.9 billion tons, whereas total lithium reserves are estimated as 86 million tons. Grid storage The Eos Energy System battery is about half the size of a shipping container and provides 1 MWh of storage. Con Edison, National Grid, Enel and GDF SUEZ began testing the battery for grid storage. Con Edison and City University of New York are testing a zinc-based battery from Urban Electric Power as part of a New York State Energy Research and Development Authority program. Eos projects that the cost of storing electricity with such EOS batteries is US$160/kWh and that it will provide electricity cheaper than a new natural-gas peaking power station. Other battery technologies range from $400 to about $1,000 a kilowatt-hour. Pressure generation When a load is applied over zinc-air batteries without access to oxygen, they generate hydrogen