Current collectors are the substrates on which anode and cathode active materials are deposited in a lithium ion battery. They do NOT contribute to battery energy density. Their role is to transport electrons from the location of redox reactions in the active material towards wiring tabs and through the load (cell phone or electric motor, etc). Traditionally, current collectors need high transverse electron conductivity parallel to the sheet plane as well as flexibility and high mechanical strength to allow for tight electrode winding into cells, under high tension. In addition, current collectors need to block any ion transport across the foil which would short the cell. These requirements have traditionally limited a choice of current collector materials to metallic foils such as copper and aluminum, circa 10 micron in thickness. It is desirable to reduce the weight of current collectors which currently can account for as high as 50% of electrode weight in a lithium ion cell. This podcast discusses professor Gogotsi’s invention of mxene based, 2D, light current collectors.