  Graphene has exhibited a wealth of fascinating properties, but is also known
not to be a superconductor. Remarkably, we show that graphene can be made a
conventional Bardeen-Cooper-Schrieffer superconductor by the combined effect of
charge doping and tensile strain. While the effect of doping is obvious to
enlarge Fermi surface, the effect of strain is profound to greatly increase the
electron-phonon coupling. At the experimental accessible doping (4E+14cm-2) and
strain (~16%) levels, the superconducting critical temperature Tc reaches as
high as ~30 K, the highest for a single-element material above the liquid
hydrogen temperature. This significantly makes graphene a commercially viable
superconductor.
