In recent years, there have been explosive interests in condensed matter physics in “spin-helical” electrons, promising potential applications ranging from spintronics to topological quantum computing. Also referred to as “spin-less” electrons (because the usual double spin degeneracy for each momentum is removed), the spin state of a spin-helical electron is uniquely determined by (or “locked to”) the momentum. In this talk, I will present our demonstration of spin-helical electrons on the surface of “topological insulators” (TI) through spin-sensitive transport measurements using ferromagnetic electrodes --- such as “spin potentiometry” demonstrating current-induced helical spin polarization [1,2]. We further observe such a current induced electron spin polarization can persist (even after the current is removed) for exceptional long lifetime --- exceeding several days at low temperature [3]. Such a remarkable “spin battery” effect is suggested as resulting from current induced nuclear spin polarization protected from relaxation by the unique real space and momentum space topologies of the spin-helical electrons on the TI surface. We further observe unusual behaviors in superconducting Josephson junctions and SQUIDs made out of our TIs [4,5,6], including a highly unconventional temperature dependence of the critical current [5] and one of the most “skewed” (non-sinusoidal) current-phase relation [6] observed in a Josephson junction. Our results suggest a topological protected, nearly ballistic Josephson transport in our TIs, paving the way to use such spin-helical electrons to realize “topological superconductors” proposed to harbor “majorana fermions” promising for topological quantum computing.