Nature Energy paper, engineers report progress toward lithium-metal batteries that charge fast – as fast as an hour. By replacing the ubiquitous copper surfaces on the negative side (the anode) of lithium-metal batteries with this lithiophobic surface made of lithium fluoride and iron, the researchers have opened a new avenue for creating more reliable, safer, higher performance lithium-metal batteries. Lithium crystals build up as the battery charges, and the lithium crystals dissolve as the battery discharges