Using solution spinning, which involves an intermediate gel-state, we obtained exceptionally strong carbon nanotube fibers that are tougher than either spider silk or any fiber used for mechanical reinforcement. We use these fibers to make 100 micron diameter supercapacitors and electronic textiles. Per weight, the energy needed to break these fibers is about 4x higher than spider dragline silk and 20x higher than steel wire. This article describes this advance, comparisons with the prior art, potential applications, and present barriers for large volume applications.