Abstract
In this contribution for the Golden Jubilee issue commemorating the 50th anniversary of the Journal of Materials Science, we will discuss the challenges and opportunities of nanoporous metals and their composites as novel energy conversion materials. In particular, we will concentrate on electrical-to-mechanical energy conversion using nanoporous metal-polymer composite materials. A materials system that mimic the properties of human skeletal muscles upon an outside stimulus is coined an ‘artificial muscle.’ In contrast to piezoceramics, nanoporous metallic materials offer a unique combination of low operating voltages, relatively large strain amplitudes, high stiffness, and strength. Here we will discuss smart materials where large macroscopic strain amplitudes up to 10 % and strain-rates up to 10−2 s−1 can be achieved in nanoporous metal/polymer composite. These strain amplitudes and strain-rates are roughly 2 and 5 orders of magnitude larger than those achieved in common actuator materials, respectively. Continuing on the theme of energy-related applications, in the summary and outlook, we discuss two recent developments toward the integration of nanoporous metals into energy conversion and storage systems. We specifically focus on the exciting potential of nanoporous metals as anodes for high-performance water electrolyzers and in next-generation lithium-ion batteries.
Highlights
A materials system that mimic the properties of human skeletal muscles upon an outside stimulus is coined an ‘artificial muscle.’
With the emphasis on miniaturization stemming from the electronics industry [1], the same push has been seen in submicron- and nanosized mechanical systems
It should be realized that the nanostructured metallic foams can show rather brittle behavior [83, 84]
Summary
With the emphasis on miniaturization stemming from the electronics industry [1], the same push has been seen in submicron- and nanosized mechanical systems. Referring to the above-mentioned actuation mechanism in metals, injection of negative charge in the space–charge region at a nanoporous metal/electrolyte interface during electroadsorption of charge compensating positive ions enhance the tensile surface stress in the metal [8, 43], resulting in an increase in compressive stress in the bulk of the ligaments and in an overall macroscopic volume shrinkage of the nanoporous metal specimen [8, 44], i.e., a negative displacement is measured experimentally.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
