Gas Evolution in Lithium-Ion Batteries: Solid versus Liquid Electrolyte.

Gas evolution in conventional lithium-ion batteries using Ni-rich layered oxide cathode materials presents a serious issue that is responsible for performance decay and safety concerns, among others. Recent findings revealed that gas evolution also occurred in bulk-type solid-state batteries. To further clarify the effect that the electrolyte has on gassing, we report in this work-to the best of our knowledge-the first study comparing gas evolution in lithium-ion batteries with NCM622 cathode material and different electrolyte types, specifically solid (β-LiPS and LiPSCl) versus liquid (LP57).

Origin of Carbon Dioxide Evolved during Cycling of Nickel-Rich Layered NCM Cathodes.

Gas formation caused by parasitic side reactions is one of the fundamental concerns in state-of-the-art lithium-ion batteries because gas bubbles might block local parts of the electrode surface, hindering lithium transport and leading to inhomogeneous current distributions. Here, we elucidate on the origin of CO, which is the dominant gaseous species associated with the layered lithium nickel cobalt manganese oxide (NCM) cathode, by implementing isotope labeling and electrolyte substitution in differential electrochemical mass spectrometry-differential electrochemical infrared spectroscopy measurements. LiCO on the NCM surface was successfully labeled with C via a process that involves its removal followed by intentional growth.

High-Throughput in Situ Pressure Analysis of Lithium-Ion Batteries.

Many degradation processes in lithium-ion batteries are accompanied by gas evolution and therefore lead to an increase in internal cell pressure. This causes serious safety concerns for state-of-the-art lithium-ion batteries, calling for a thorough investigation of the origin and the magnitude of such processes. Herein we introduce a multichannel in situ pressure measurement system that allows for the high-throughput quantification of gas evolution under realistic battery conditions.

Electrochemical CO reduction on Au surfaces: mechanistic aspects regarding the formation of major and minor products.

In the future, industrial CO electroreduction using renewable energy sources could be a sustainable means to convert CO and water into commodity chemicals at room temperature and atmospheric pressure. This study focuses on the electrocatalytic reduction of CO on polycrystalline Au surfaces, which have high activity and selectivity for CO evolution. We explore the catalytic behavior of polycrystalline Au surfaces by coupling potentiostatic CO electrolysis experiments in an aqueous bicarbonate solution with high sensitivity product detection methods.

Engineering Cu surfaces for the electrocatalytic conversion of CO: Controlling selectivity toward oxygenates and hydrocarbons.

In this study we control the surface structure of Cu thin-film catalysts to probe the relationship between active sites and catalytic activity for the electroreduction of CO to fuels and chemicals. Here, we report physical vapor deposition of Cu thin films on large-format (∼6 cm) single-crystal substrates, and confirm epitaxial growth in the <100>, <111>, and <751> orientations using X-ray pole figures. To understand the relationship between the bulk and surface structures, in situ electrochemical scanning tunneling microscopy was conducted on Cu(100), (111), and (751) thin films.

Electrocatalytic conversion of carbon dioxide to methane and methanol on transition metal surfaces.

Fuels and industrial chemicals that are conventionally derived from fossil resources could potentially be produced in a renewable, sustainable manner by an electrochemical process that operates at room temperature and atmospheric pressure, using only water, CO2, and electricity as inputs. To enable this technology, improved catalysts must be developed. Herein, we report trends in the electrocatalytic conversion of CO2 on a broad group of seven transition metal surfaces: Au, Ag, Zn, Cu, Ni, Pt, and Fe.

Insights into the electrocatalytic reduction of CO₂ on metallic silver surfaces.

The electrochemical reduction of CO2 could allow for a sustainable process by which renewable energy from wind and solar are used directly in the production of fuels and chemicals. In this work we investigated the potential dependent activity and selectivity of the electrochemical reduction of CO2 on metallic silver surfaces under ambient conditions. Our results deepen our understanding of the surface chemistry and provide insight into the factors important to designing better catalysts for the reaction.