Energy storage devices such as batteries and supercapacitors provide a seamless interface between energy generation and its real-time utilization. Supercapacitors have gained tremendous research interest due to their high-performance characteristics. The critical objective is to simultaneously achieve excellent energy density, uncompromised power density, high rate capability, and superior cyclic stability. Typically, the development of an outstanding supercapacitor electrode translates to designing a system with the following cardinal themes: large ion-accessible surface area, high electrical conductivity, rapid charge transport, and high electrochemical stability. The unnerving task of accomplishing all the above characteristics in a single electrode is the major Achilles heel in the large-scale commercial viability of supercapacitor technology.

Electrochemical energy storage (EES) devices play a crucial role in our pursuit of non-polluting, green technologies. With the characteristic short ion-diffusion length, nano-scale materials are considered promising for the realization of high-performance EES. In contrast, existing nano-textured electrodes' inadequate ion-accessible surface area and laborious multi-step synthesis technology limits their overall performance. This DCU research collaboration provides the first demonstration of sub-homologous temperature solid-state nano-moulding in a crystalline alloy, resulting in a highly ordered hierarchical nano-tubular architecture with outstanding electrochemical energy storage. Benefitting from increased material fluidity at a high strain rate, a short burst of physical deformation facilitated the material flow into the nano-moulds. The chemically dealloyed nano-tubular electrode demonstrated excellent volumetric specific capacitance of ∼1000 F/cm3 at 5.5 A/cm3 current density. A symmetric supercapacitor device showcased an exceptional energy density of ∼90 Wh/L at a power density of ∼0.5 kW/L and excellent cyclic stability of 94% after 10,000 cycles. The device-level technology readiness is demonstrated by successfully integrating multiple small devices to operate high-power electronic components, setting the way forward for advanced energy storage applications.