nickel foam   

https://www.attelements.com/foams/nickel-foam.html

Nickel Foam has interlinked cellular structure with high porosity of > 95%. Due to high porosity, Nickel foam offers a very large surface area and is used in applications requiring large surface to volume ratio. It is popularly used as photocatalytic substrate, as an electrode in photoelectrochemical systems and for electrode develoment (Platinum coated electrodes) in Fuel cells. In all these applications, large surface area is an utmost requirement. As increased surface area enhances the rate of surface reaction thus increases the efficiency of the system. Nickel Foam also finds application in supercapacitors as a current collector. Also due to its porous structure and high strength it is also used for vibration and noise absorption applications.