Heterogeneous Photocatalysis and Sensitized Photolysis for Enhanced Degradation of Bisphenol A and its Analogues

This work deals with elucidation of bisphenols transformations occurring in the processes of TiO2 photocatalysis and sensitized photolysis. A special attention is paid to the clarification of the mechanisms of the reactive oxygen species generation. In particular, the work investigates the sources and mobility of photocatalytically generated OH radicals by isotopic labeling experiments and explores the role of natural organic matter as a sensitizer in the sunlight photolysis of bisphenols

In situ analysis of gas evolution in liquid- and solid-electrolyte-based batteries with current and next-generation cathode materials

The operation of combined mass spectrometry and electrochemistry setups has recently become a powerful approach for the in situ analysis of gas evolution in batteries. It allows for real-time insights and mechanistic understanding into different processes, including battery formation, operation, degradation, and behavior under stress conditions. Important information is gained on the safety and stability window as well as on the effect of protecting strategies, such as surface coatings, dopings, and electrolyte additives. This review primarily aims at summarizing recent findings on the gassing behavior in different kinds of liquid- and solid-electrolyte-based batteries, with emphasis placed on novel cathode-active materials and isotope labeling experiments, to highlight the relevance of in situ gas analysis for elucidation of reaction mechanisms. Various instrumental and experimental approaches are presented to encourage and inspire both novices and experienced scientists in the field

Facile solid-state synthesis of a layered Co-free, Ni-rich cathode material for all-solid-state batteries

Layered Ni-rich oxides are attractive cathode active materials for secondary battery applications. Combining them with inorganic superionic conductors and high-capacity anodes can significantly increase energy density. Herein we successfully synthesized spherical secondary particles of a Mn-substituted LiNiO$_2$, LiNi$_{0.95}$Mn$_{0.05}$O$_2$ (a Co-free NMX material), for use in bulk-type lithium-thiophosphate-based all-solid-state batteries

Elucidating Gas Evolution of Prussian White Cathodes for Sodium‐ion Battery Application: The Effect of Electrolyte and Moisture

As global energy storage demand increases, sodium-ion batteries are often considered as an alternative to lithium-ion batteries. Hexacyanoferrate cathodes, commonly referred to as Prussian blue analogues (PBAs), are of particular interest due their low-cost synthesis and promising electrochemical response. However, because they consist of ~50 wt% cyanide anions, a possible release of highly toxic cyanide gases poses a significant safety risk. Previously, we observed the evolution of (CN)2 during cycling via differential electrochemical mass spectrometry (DEMS), but were unable to determine a root cause or mechanism. In this work, we present a systematical investigation of the gas evolution of Prussian white (PW) with different water content via DEMS. While H2 is the main gas detected, especially in hydrated PW and during overcharge (4.6 V vs. Na+/Na), the evolution of CO2 and (CN)2 depends on the electrolyte conductive salt. The use of oxidative NaClO4 instead of NaPF6 is the leading cause for the formation of (CN)2. Mass spectrometric evidence of trace amounts of HCN is also found, but to a much lower extent than (CN)2, which is the dominant safety risk when using NaClO4-containing electrolyte, which despite being a good model salt, is not a viable option for commercial applications

The effect of configurational entropy on acoustic emission of P2-type layered oxide cathodes for sodium-ion batteries

Sodium-ion batteries (SIBs) see intensive research and commercialization efforts, aiming to establish them as an alternative to lithium-ion batteries. Among the reported cathode material families for SIBs, Na-deficient P2-type layered oxides are promising candidates, benefiting from fast sodium diffusion and therefore high charge/discharge rates. However, upon sodium extraction at high potentials, a transition from the P2 to O2 phase occurs, with the corresponding change in cell volume resulting in particle fracture and capacity degradation. A possible solution to this is to increase configurational entropy by introducing more elements into the transition-metal layer (so-called high-entropy concept), leading to some kind of structural stabilization. In this work, the acoustic emission (AE) of a series of P2-type layered oxide cathodes with increasing configurational entropy [Na0.67(Mn0.55Ni0.21Co0.24)O2, Na0.67(Mn0.45Ni0.18Co0.24Ti0.1Mg0.03)O2 and Na0.67(Mn0.45Ni0.18Co0.18Ti0.1Mg0.03Al0.04Fe0.02)O2] is recorded during SIB operation and correlated to the materials properties, namely change in c lattice parameter and cracking behavior. A structure-property relationship between entropy, manifested in the extent of phase transition, and detected AE is derived, supported by the classification of signals by peak frequency. This classification in combination with microscopy imaging allows to distinguish between inter- and intragranular fracture. Relatively more intergranular and less intragranular crack formation is observed with increasing configurational entropy

Transition-metal interdiffusion and solid electrolyte poisoning in all-solid-state batteries revealed by cryo-TEM

Using scanning transmission electron microscopy, along with electron energy loss spectroscopy, under cryogenic conditions, we demonstrate transition-metal dissolution from a layered Ni-rich oxide cathode material and subsequent diffusion into the bulk of a lithium thiophosphate solid electrolyte during electrochemical cycling. This problem has previously only been considered for liquid-electrolyte-based batteries

Atomic Layer Deposition Derived Zirconia Coatings on Ni‐Rich Cathodes in Solid‐State Batteries: Correlation Between Surface Constitution and Cycling Performance

Protective coatings are required to address interfacial incompatibility issues in composite cathodes made from Ni-rich layered oxides and lithium thiophosphate solid electrolytes (SEs), one of the most promising combinations of materials for high energy and power density solid-state battery (SSB) applications. Herein, the preparation of conformal ZrO2 nanocoatings on a LiNi0.85Co0.10Mn0.05O2 (NCM85) cathode-active material (CAM) by atomic layer deposition (ALD) is reported and the structural and chemical evolution of the modified NCM85 upon heat treatment—a post-processing step often required to boost battery performance—is investigated. The coating properties are shown to have a strong effect on the cyclability of high-loading SSB cells. After mild annealing (≈400 °C), the CAM delivers high specific capacities (≈200 mAh g−1 at C/10) and exhibits improved rate capability (≈125 mAh g−1 at 1C) and stability (≈78% capacity retention after 200 cycles at 0.5C), enabled by effective surface passivation. In contrast, annealing temperatures above 500 °C lead to the formation of an insulating interphase that negatively affects the cycling performance. The results of this study demonstrate that the preparation conditions for a given SE/CAM combination need to be tailored carefully and ALD is a powerful surface-engineering technique toward this goal