Visualization of Na-diglyme co-intercalation induced few-layer graphene expansion and SEI formation using operando electrochemical atomic force microscopy

Diglyme solvated sodium-ion complexes enable the superfast co-intercalation of charge carriers (Na+) into graphite carbon interlayers,[1] providing unprecedented prospects for the application of low-cost graphite carbon as sodium-ion battery anode materials. Insights into this novel co-intercalation process are essential for enhancing the electrochemical performance of co-intercalation-based energy storage systems.[2, 3] Meanwhile, the paradox role of the co-existence of solid electrolyte interphase (SEI) and solvent co-intercalation behaviors needs to be further clarified.[4, 5] This presentation focuses on the real-space operando observation of the SEI formation, as well as Na-diglyme co-intercalation induced carbon-interlayers expansion in few-layer graphene as sodium anode electrodes. The few-layer graphene grown on the Ni current collector was patterned by Ar/O2 plasma to serve as a model anode electrode. The co-intercalation phenomenon was then directly observed by monitoring the interlayer spacing expansion using operando electrochemical atomic force microscopy (EC-AFM). The electrolyte decomposition was clearly observed on the few-layer graphene surfaces, and the anisotropic chemical components of SEI formed on graphite edge and basal planes were confirmed by XPS. The characterization results indicate that the SEI formed on the graphite edge planes cannot act as a physical ‘barrier’ to fully seal the edge sites and prevent the solvent co-intercalation into the carbon interlayers. This is due to the huge interlayer spacing expansion and contraction rate (300%) upon the intercalation/deintercalation of sodium-diglyme complex as confirmed by operando electrochemical EC-AFM characterisations

Geoscience after IT: Part N. Cumulated references

Cumulated references for papers in Geoscience after IT: A view of the present and future impact of Information Technology on Geoscienc

Nanoarchitecture factors of solid – electrolyte interphase formation via 3D nano-rheology microscopy and surface force-distance spectroscopy

The solid electrolyte interphase in rechargeable Li-ion batteries, its dynamics and, significantly, its nanoscale structure and composition, hold clues to high-performing and safe energy storage. Unfortunately, knowledge of solid electrolyte interphase formation is limited due to the lack of in situ nano-characterization tools for probing solid-liquid interfaces. Here, we link electrochemical atomic force microscopy, three-dimensional nano-rheology microscopy and surface force-distance spectroscopy, to study, in situ and operando, the dynamic formation of the solid electrolyte interphase starting from a few 0.1 nm thick electrical double layer to the full three-dimensional nanostructured solid electrolyte interphase on the typical graphite basal and edge planes in a Li-ion battery negative electrode. By probing the arrangement of solvent molecules and ions within the electric double layer and quantifying the three-dimensional mechanical property distribution of organic and inorganic components in the as-formed solid electrolyte interphase layer, we reveal the nanoarchitecture factors and atomistic picture of initial solid electrolyte interphase formation on graphite-based negative electrodes in strongly and weakly solvating electrolytes

Sources of dissolved inorganic nitrogen in a coastal lagoon adjacent to a major metropolitan area, Miami Florida (USA)

•A range of biota (algae and sea grasses) shows enriched δ15N close to the coast.•Enriched signals are evident in the particulate and sedimentary organic material.•δ15N signals are correlated with high inputs of dissolved inorganic matter.•The enriched values support the presence of a sewage related component.•The δ15N could arise from the local landfill, injected wastewater, or septic systems. Between 2006 and 2007, a study was carried out to determine the relative importance of natural and anthropogenic input of nitrogen into Biscayne Bay (South Florida, USA) using δ13C and δ15N values of algae, seagrasses, and particulate organic material, δ18O and δ15N of the NO3- and δ13C of the dissolved inorganic carbon. The δ15N values of all components showed a strong east to west gradient approaching more positive values (+7 to +10‰) close to the land-sea interface. The nitrogen could have emanated from the local waste water treatment plant, septic systems within the region, or nitrogen which had been affected by denitrification and leached from the local landfill, wastewater which had been injected into the Floridan aquifer and leaked back to the surface, and/or some other as yet unidentified source. The measured NO3- δ15N and δ18O values indicated that the dissolved nitrate originated from anthropogenic sources and was fractionated during assimilation