Electrocatalysis will play a key role in future energy conversion and storage technologies, such as water electrolysers, fuel cells and metal-air batteries. Molecular interactions between chemical reactants and the catalytic surface control the activity and efficiency, and hence need to be optimized; however, generalized experimental strategies to do so are scarce. Here we show how lattice strain can be used experimentally to tune the catalytic activity of dealloyed bimetallic nanoparticles for the oxygen-reduction reaction, a key barrier to the application of fuel cells and metal-air batteries. We demonstrate the core-shell structure of the catalyst and clarify the mechanistic origin of its activity. The platinum-rich shell exhibits compressive strain, which results in a shift of the electronic band structure of platinum and weakening chemisorption of oxygenated species. We combine synthesis, measurements and an understanding of strain from theory to generate a reactivity-strain relationship that provides guidelines for tuning electrocatalytic activity.

Lithium-ion-conducting solid electrolytes hold promise for enabling high-energy battery chemistries and circumventing safety issues of conventional lithium batteries. Achieving the combination of high ionic conductivity and a broad electrochemical window in solid electrolytes is a grand challenge for the synthesis of battery materials. Herein we show an enhancement of the room-temperature lithium-ion conductivity by 3 orders of magnitude through the creation of nanostructured Li(3)PS(4). This material has a wide electrochemical window (5 V) and superior chemical stability against lithium metal. The nanoporous structure of Li(3)PS(4) reconciles two vital effects that enhance the ionic conductivity: (1) the reduction of the dimensions to a nanometer-sized framework stabilizes the high-conduction β phase that occurs at elevated temperatures, and (2) the high surface-to-bulk ratio of nanoporous β-Li(3)PS(4) promotes surface conduction. Manipulating the ionic conductivity of solid electrolytes has far-reaching implications for materials design and synthesis in a broad range of applications, including batteries, fuel cells, sensors, photovoltaic systems, and so forth.

HSAB theory predicts the design of air-stable, high-conduction sulfide based solid electrolytes.