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Electrolyte additives are indispensable to enhance the performance of Li-ion batteries. Lithium bis(oxalato)borate (LiBOB) has been explored for many years, as it improves both cathode and anode performance. No consensus regarding its reaction mechanisms has, however, been established. A model operando study combining attenuated total reflection infrared spectroscopy (ATR-FTIR), electrochemical quartz crystal microbalance (EQCM), and online electrochemical mass spectrometry (OEMS) is herein presented to elucidate LiBOB reduction and electrode/electrolyte interphases thus formed. Reduction of the BOB– ion sets in at ∼1.8 V with solid lithium oxalate and soluble oxalatoborates as the main products. The reduced BOB– ion also reacts with itself and its environment to evolve CO2, which in turn impacts the interphase formed on the negative electrode. This study provides further insights into the reduction pathways of LiBOB and how they contribute to the interphase formation.

Introducing small volumes of organosilicon-containing additives as part of lithium-ion battery (LIB) electrolyte engineering has been getting a lot of attention owing to these additives’ multifunctional properties. Tris(trimethylsilyl)phosphate (TMSPa) is a prominent member of this class of additives and scavenges Lewis bases such as water, although the rate at which the reaction occurs and the fate of the resultant product in the battery system still remain unknown. Herein, we have employed complementary nuclear magnetic resonance and gas chromatography–mass spectrometry to systematically study the reactivity of TMSPa with water in conventional organic carbonate solvents mimicking the Li-ion cell environment. The reaction products are identified, and a working reaction pathway is proposed by following the chemical evolution of the products over varying time and temperatures. We found that the main reaction products are trimethylsilanol (TMSOH) and phosphoric acid (H3PO4); however, various P–O–Si-containing intermediates were also found. Similar to water, the Lewis base TMSOH can undergo reaction with TMSPa at room temperature to form hexamethyldisiloxane and can also activate ethylene carbonate (EC) ring-opening reactions at elevated temperatures (≥80 °C), yielding a TMS derivative with ethylene glycol (TMS-EG). While the formation of TMS-EG at the expense of EC is in principle an unwanted parasitic reaction, it should be noted that this reaction is only activated at elevated temperatures in comparison to EC ring-opening by H2O, which takes place at ≥40 °C. Thus, the study underlines the advantages of organo-silicon compounds as electrolyte additives. Elucidating the reaction mechanism in model systems like this is important for future studies of similar additives in order to improve the accuracy of additive exploration in LIBs.

Ethylene carbonate (EC) and vinylene carbonate (VC) are the archetypical electrolyte solvent and additive in Li-ion batteries (LIBs), respectively. However, our understanding of their reaction pathways remains incomplete. Herein, the reaction pathways of EC and VC are explored by using online electrochemical mass spectrometry complemented by nuclear magnetic resonance analysis. For EC, reduction occurs through two distinct pathways <0.8 V vs Li+/Li, one yielding C2H4 and the other yielding CO, depending on the electrode potential and the EC concentration. The CO-releasing pathway does not contribute to the solid electrolyte interphase formation. For VC, reduction commences at <1.9 V, but CO2 gas evolution proceeds through a chemical step via a nucleophilic attack and VC ring opening. Additionally, VC scavenges H2O and reduced protons via hydrolysis and via proton abstraction from the carbon electrode to form EC. Our study uncovers further reaction pathways and underscores the unique properties of EC and VC, both individually and in combination, and elucidates their roles in influencing the formation process in Li-ion batteries.

Vinylene carbonate (VC) is the most commonly applied performance-enhancing electrolyte additives in Li-ion batteries to date. Despite numerous studies, there is a lack of consensus regarding the various reaction pathways of VC and their implications. VC has primarily been observed to either polymerize forming poly(vinylene carbonate) (poly(VC)) or decompose releasing major amounts of CO2, two seemingly contradictory processes. Herein, we present evidence of additional reaction pathways of VC highlighting its role as a H2O scavenging agent. In contrast to the typical electrolyte solvent ethylene carbonate, VC reacts much more rapidly with water impurities, especially when in contact with hydroxides, forming products less likely to influence cell performance. Efficient removal of water and hydroxides is essential to preserve the stability of Li-ion electrolyte solvent and salt, hence guaranteeing a long lifetime of the battery. Model studies pinpointing reaction pathways of electrolytes and additives, as presented herein, are critical not only to improve modern Li-ion cells but also to establish design principles for future battery chemistries.

Rechargeable magnesium batteries could provide future energy storage systems with high energy density. One remaining challenge is the development of electrolytes compatible with the negative Mg electrode, enabling uniform plating and stripping with high Coulombic efficiencies. Often improvements are hindered by a lack of fundamental understanding of processes occurring during cycling, as well as the existence and structure of a formed interphase layer at the electrode/electrolyte interface. Here, a magnesium model electrolyte based on magnesium bis(trifluoromethanesulfonyl)imide (Mg(TFSI)2) and MgCl2 with a borohydride as additive, dissolved in dimethoxyethane (DME), was used to investigate the initial galvanostatic plating and stripping cycles operando using electrochemical quartz crystal microbalance with dissipation monitoring (EQCM-D). We show that side reactions lead to the formation of an interphase of irreversibly deposited Mg during the initial cycles. EQCM-D based hydrodynamic spectroscopy reveals the growth of a porous layer during Mg stripping. After the first cycles, the interphase layer is in a dynamic equilibrium between the formation of the layer and its dissolution, resulting in a stable thickness upon further cycling. This study provides operando information of the interphase formation, its changes during cycling and the dynamic behavior, helping to rationally develop future electrolytes and electrode/electrolyte interfaces and interphases.

Optimization of cell formation during lithium -ion battery (LIB) production is needed to reduce time and cost. Operando gas analysis can provide unique insights into the nature, extent, and duration of the formation process. Herein we present the development and application of an Online Electrochemical Mass Spectrometry (OEMS) design capable of monitoring gas evolution and consumption in both model coin-cells (Q = 0.72 mAh) with a graphite/electrolyte weight-ratio of 1:12.5 and large-format Li -ion cells (Q = 72 Ah) with a graphite/electrolyte weight -ratio of 1:0.63 during operation. Although the composition and amounts of gas are highly comparable, even when validated against ex -situ analysis, the gas release rate is lower from the larger cell size and likely limited by gas bubble transport through the electrode stack of the cell during formation. Higher temperatures accelerate the formation process, but also alters the composition and extent of gas released. Apart from providing novel insights into the formation processes of large -format Li-ion cells, our OEMS setup offers an opportunity for the battery manufacturing and automotive industry to explore the impact of battery formation and/or operating conditions on gas evolution in next -generation Li-ion batteries of any size.

A growing concern for climate change puts high demands on electricity from renewable energy sources. Varying results have been reported on the impacts of wind power on terrestrial mammals, e.g. effects on migration corridors and grazing habitat of reindeer (Rangifer tarandus tarandus), increased stress-hormones in roe deer (Capreolus capreolus), lowered breeding success in wolves (Canis lupus), and lowered activity and habitat shifts for moose (Alces alces). Using a retrospective dataset of moose harvest (2012-2020) from Sweden and Norway, I examined how harvest at three management levels of various size (Moose Management Areas, Moose Management Units and Hunting team areas/Game management areas) was affected by the establishment of wind parks. Additional covariates were the occurrence of large predators (wolf and brown bear (Ursus arctos)), road densities, and 12-year accumulated forest loss. Harvest significantly correlated with wind park establishment at the small and middle levels of moose management. Harvest was affected by the distance to closest wind parks, the number of turbines in wind parks and, at the smallest management level, by the wind turbines height. At the small level, the number of turbines temporarily had a positive correlation with moose harvest during construction phase but shifted to negative during the operative phase. Such pattern was possibly resulting from allocated hunting efforts in relation to altered movement patterns of moose in response to wind park establishment. At the large level, while wind turbines had no significant effect, predator occurrence and gravel road density affected moose harvest. At the middle level, harvest density was affected by wolf occurrence and proportion of young forest stands, but not by occurrence of brown bear. Results show that wind power establishment can affect hunting, an important leisure activity for people on the countryside. Reduced harvests risk to increase browsing damages in forestry and moose-v