Carbon nanotubes (CNT) lie at the crossroads of a multitude of different next generation technologies. Among the most promising of these are structural reinforcement of composites and high energy density supercapacitors. Our work presents a unique approach where CNT grown on stainless steel meshes are used to simultaneously mechanically reinforce a structural composite and function as a high energy density supercapacitor electrodes. The multifunctional design is enabled via an epoxy-ionic liquid matrix/electrolyte and with alternating layers of insulating fiberglass or Kevlar and CNT grown on steel mesh. The resulting composite energy storage devices exhibit mechanical strength greater than 85 MPa approaching that of commercial composites and with an energy density of up to 3 mWh/kg for a fully packaged system. Furthermore in-situ mechano-electro-chemical tests demonstrate that the capacitance is completely maintained throughout the elastic regime up to the maximum tensile loading >85 MPa.