High strain-rate driven nano-tubular architecture in NiMn alloy for supercapacitor electrodes

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. Herein, we provide 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. © 2023 Elsevier B.V. All rights reserved.