Probing lithium mobility at a solid electrolyte surface.

Solid-state electrolytes overcome many challenges of present-day lithium ion batteries, such as safety hazards and dendrite formation. However, detailed understanding of the involved lithium dynamics is missing due to a lack of in operando measurements with chemical and interfacial specificity. Here we investigate a prototypical solid-state electrolyte using linear and nonlinear extreme-ultraviolet spectroscopies.

Author Correction: Eliminating dissolution of platinum-based electrocatalysts at the atomic scale.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Eliminating dissolution of platinum-based electrocatalysts at the atomic scale.

A remaining challenge for the deployment of proton-exchange membrane fuel cells is the limited durability of platinum (Pt) nanoscale materials that operate at high voltages during the cathodic oxygen reduction reaction. In this work, atomic-scale insight into well-defined single-crystalline, thin-film and nanoscale surfaces exposed Pt dissolution trends that governed the design and synthesis of durable materials. A newly defined metric, intrinsic dissolution, is essential to understanding the correlation between the measured Pt loss, surface structure, size and ratio of Pt nanoparticles in a carbon (C) support.

Crystal Orientation-Dependent Reactivity of Oxide Surfaces in Contact with Lithium Metal.

Understanding ionic transport across interfaces between dissimilar materials and the intrinsic chemical stability of such interfaces is a fundamental challenge spanning many disciplines and is of particular importance for designing conductive and stable solid electrolytes for solid-state Li-ion batteries. In this work, we establish a surface science-based approach for assessing the intrinsic stability of oxide materials in contact with Li metal. Through a combination of experimental and computational insights, using Nb-doped SrTiO (Nb/STO) single crystals as a model system, we were able to understand the impact of crystallographic orientation and surface morphology on the extent of the chemical reactions that take place between surface Nb, Ti, and Sr upon reaction with Li.

Controlling the termination and photochemical reactivity of the SrTiO(110) surface.

SrTiO(110) orientated crystals have been heated to temperatures between 1000 °C and 1200 °C in air, alone or in the presence of powder reservoirs of TiO or SrTiO. In these conditions, the surface is terminated by two types of atomically flat terraces. One has a relatively higher surface potential and promotes the photochemical reduction of silver (it is photocathodic) and the other has a relatively lower surface potential and promotes the photochemical oxidation of lead (it is photoanodic).

Buried Charge at the TiO/SrTiO (111) Interface and Its Effect on Photochemical Reactivity.

High-temperature annealing in air is used to produce SrTiO (111) surfaces with two types of atomically flat terraces: those that promote photoanodic reactions and those that promote photocathodic reactions. Surface potential measurements show that the photocathodic terraces have a relatively more positive surface potential than the photoanodic terraces. After depositing thin TiO films on the surface, from 1 to 13 nm thick, the surface of the film above the photocathodic terraces also has photocathodic properties, similar to those of the bare surface.

Two-dimensional polyaniline nanostructure to the development of microfluidic integrated flexible biosensors for biomarker detection.

In this work, we report a flexible field-effect-transistor (FET) biosensor design based on two-dimensional (2-D) polyaniline (PANI) nanostructure. The flexible biosensor devices were fabricated through a facile and inexpensive method that combines top-down and bottom-up processes. The chemically synthesized PANI nanostructure showed excellent p-type semiconductor properties as well as good compatibility with flexible design.