Public debates about climate futures increasingly oscillate between the extremes of catastrophism and cruel eco-optimism. While different social imaginaries of climate change are part of sociological ...debates, to date this specific dynamic has not been extensively explored. By examining recent examples of climate change coverage and analyzing new ideological trends such as "apocalyptic optimism," I situate this imaginative impasse in the sociological debate about social imaginaries of climate change. While catastrophism itself is nothing new, the specific feedback loop between catastrophism and cruel eco-optimism distinguishes today's social imaginary from that of the 1950s and 1970s. Drawing on recent decolonial and indigenous concepts such as "settler apocalypticism" and "carbon imaginary" that offer a critique of the fixation on future catastrophes, my argument is that the oscillation between despair and denial has a colonial undertone and can thus be interpreted as a colonial lack of imagination. Overall, my aim is twofold: First, I want to direct attention towards the colonial dimension of the imaginative impasse. The impression that it is easier to imagine the end of the world than the end of capitalism is itself an effect of colonial ways of envisioning time and history. Second, I want to propose an interdisciplinary angle to think about the problem space of climate futures and corresponding political feelings by bringing into conversation sociological assessments of the present, studies on climate feelings, decolonial and indigenous studies, eco-socialist interventions and some authors of early critical theory. Against this background, I reference the work of Günther Anders (2003) and ask what a training of the imagination would signify in today's context.
Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) typically reveal a sudden failure in Li metal cells particularly with high energy density/voltage positive electrodes, e.g. LiNi
Mn
Co
...O
(NMC622), which is visible in an arbitrary, time - and voltage independent, "voltage noise" during charge. A relation with SPE oxidation was evaluated, for validity reasons on different active materials in potentiodynamic and galvanostatic experiments. The results indicate an exponential current increase and a potential plateau at 4.6 V vs. Li|Li
, respectively, demonstrating that the main oxidation onset of the SPE is above the used working potential of NMC622 being < 4.3 V vs. Li|Li
. Obviously, the SPE│NMC622 interface is unlikely to be the primary source of the observed sudden failure indicated by the "voltage noise". Instead, our experiments indicate that the Li | SPE interface, and in particular, Li dendrite formation and penetration through the SPE membrane is the main source. This could be simply proven by increasing the SPE membrane thickness or by exchanging the Li metal negative electrode by graphite, which both revealed "voltage noise"-free operation. The effect of membrane thickness is also valid with LiFePO
electrodes. In summary, it is the cell set-up (PEO thickness, negative electrode), which is crucial for the voltage-noise associated failure, and counterintuitively not a high potential of the positive electrode.
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In this work, different Li salt concentrations and ionic conductivities of poly(ethylene oxide)-based solid polymer electrolytes (PEO-based SPEs) are correlated with the performance ...of LiNi0.6Mn0.2Co0.2O2 (NMC622)||Li full cells. While the SPEs with different salt concentrations behave similarly in NMC622||Li cells at 60 °C, their influence on the specific capacities is significant at 40 °C. Below a distinct salt concentration, i.e. > 20:1 (EO:Li), a sudden blocking-type polarization appears, indicatable by an almost vertical voltage profile, both in full and in Li||Li symmetric cells. The corresponding time and current density for this polarization-type is shown to mathematically fit with the Sand equation, which subsequently allows calculation of DLi+. According this relation, lack of Li+ in the electrolyte close to the electrode surface can be concluded to be the origin of this polarization, but is shown to appear only for “kinetically limiting” conditions e.g. above a threshold current density, above a threshold SPE thickness and/or below a threshold salt concentration (ionic conductivity), i.e. at mass transfer limiting conditions. With the support of this relation, maximal applicable current densities and/or SPE thicknesses can be calculated and predicted for SPEs.
Fast charging is considered to be a key requirement for widespread economic success of electric vehicles. Current lithium‐ion batteries (LIBs) offer high energy density enabling sufficient driving ...range, but take considerably longer to recharge than traditional vehicles. Multiple properties of the applied anode, cathode, and electrolyte materials influence the fast‐charging ability of a battery cell. In this review, the physicochemical basics of different material combinations are considered in detail, identifying the transport of lithium inside the electrodes as the crucial rate‐limiting steps for fast‐charging. Lithium diffusion within the active materials inherently slows down the charging process and causes high overpotentials. In addition, concentration polarization by slow lithium‐ion transport within the electrolyte phase in the porous electrodes also limits the charging rate. Both kinetic effects are responsible for lithium plating observed on graphite anodes. Conclusions drawn from potential and concentration profiles within LIB cells are complemented by extensive literature surveys on anode, cathode, and electrolyte materials—including solid‐state batteries. The advantages and disadvantages of typical LIB materials are analyzed, resulting in suggestions for optimum properties on the material and electrode level for fast‐charging applications. Finally, limitations on the cell level are discussed briefly as well.
The limited fast‐charging capabilities of state‐of‐the‐art lithium‐ion batteries hinder market adoption of electric vehicles. In this review, the physicochemical basics influencing fast charging are elucidated and material aspects are analyzed, resulting in lithium transport within the electrodes (active materials and electrolyte therein) as the crucial rate‐limiting process. Thus, ways to improve materials regarding their fast‐charging capabilities are suggested.
Electrochemical impedance spectroscopy (EIS) using alternating currents is a widely established technique to investigate kinetic aspects of batteries and their components, though it requires an ...interruption of battery operation with extra measurement time and effort. In this work, EIS is compared with the conventional galvanostatic (constant current) technique, which is based on direct currents, being the standard operation mode of batteries. Data from constant current measurements not only are representing application conditions but also are automatically and continuously generated during routine charge/discharge processes, i.e., without extra measurement efforts, and do give kinetic insights via the characteristic overvoltage (= resistance-reasoned voltage rise/decrease), as well. In fact, distinguishing between even very similar values for ohmic (R Ω), charge transfer (R ct ), and mass transport (R mt ) resistances can be done via analysis of overvoltage data from constant current measurements, as exemplarily demonstrated in symmetric Li||Li and LiNi0.6Mn0.2Co0.2O2 (NMC622)||Li cells with poly(ethylene oxide)-based solid polymer electrolyte, finally proving their validity. From a practical point of view, direct-current methods can be beneficial for R&D of kinetic aspects in batteries, as data is directly obtained and, thus, application-oriented.
Frequently, poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) reveal a failure with high-voltage electrodes, e.g. LiNi0.6Mn0.2Co0.2O2 in lithium metal batteries, which can be ...monitored as an arbitrary appearance of a “voltage noise” during charge and can be attributed to Li dendrite-induced cell micro short circuits. This failure behavior disappears when incorporating linear PEO-based SPE in a semi-interpenetrating network (s-IPN) and even enables an adequate charge/discharge cycling performance at 40°C. An impact of any electrolyte oxidation reactions on the performance difference can be excluded, as both SPEs reveal similar (high) bulk oxidation onset potentials of ≈4.6 V versus Li|Li+. Instead, improved mechanical properties of the SPE, as revealed by compression tests, are assumed to be determining, as they mechanically better withstand Li dendrite penetration and better maintain the distance of the two electrodes, both rendering cell shorts less likely.
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•PEO-based solid polymer electrolytes (SPEs) are stable up to 4.6 V versus Li|Li+•But, linear PEO-based SPE results in a “voltage noise-failure” in NMC‖Li cells•Failure disappears when PEO is incorporated in a semi-interpenetrating network•Charge/discharge cycling possible even at 40°C in NMC622‖Li cells
Polymer Chemistry; Electrochemistry; Electrochemical Energy Storage
Lithium batteries with solid polymer electrolytes (SPEs) and mobile ions are prone to mass transport limitations, that is, concentration polarization, creating a concentration gradient with Li+-ion ...(and counter-anion) depletion toward the respective electrode, as can be electrochemically observed in, for example, symmetric Li||Li cells and confirmed by Sand and diffusion equations. The effect of immobile anions is systematically investigated in this work. Therefore, network-based SPEs are synthesized with either mobile (dual-ion conduction) or immobile anions (single-ion conduction) and proved via solvation tests and nuclear magnetic resonance spectroscopy. It is shown that the SPE with immobile anions does not suffer from concentration polarization, thus disagreeing with Sand and diffusion assumptions, consequently suggesting single-ion (Li+) transport via migration instead. Nevertheless, the practical relevance of single-ion conduction can be debated. Under practical conditions, that is, below the limiting current, the concentration polarization is generally not pronounced with DIC-based electrolytes, rendering the beneficial effect of SIC redundant and DIC a better choice due to better kinetical aspects under these conditions. Also, the observed dendritic Li in both electrolytes questions a relevant impact of mass transport on its formation, at least in SPEs.
Pure, i.e. , linear poly(ethylene oxide)-based solid polymer electrolyte (PEO-based SPE) as a common benchmark system for Li metal batteries (LMBs) is frequently assumed to be unsuitable for high ...voltage applications e.g. , with LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622)-based cathodes. In fact, a destructive failure appears immediately after cell operation, seen by a random-like “voltage noise” during charge, rendering continuous charge/discharge cycling in e.g. , NMC622||Li cells not possible. Counterintuitively, this failure is a result of short-circuits in the course of e.g. , Li dendrite penetration. It is shown that the distance between the electrodes plays a crucial role. This failure is more likely with a lower distance, particularly when the SPE is mechanically prone to shrinkage, for example at higher temperatures as systematically revealed by mechanical compression tests. Additionally, the active mass loading has a crucial impact on short circuits, and thus the “voltage noise” failure, as well. An effective and practically simple solution to realize cell operation with a PEO-based SPE is the incorporation of a spacer between the electrodes. This modification prevents the detrimental shrinkage and enables charge/discharge cycling performance in NMC622||Li cells with a defined and constant electrode distance, thus without voltage noise, and finally fulfills a reasonable benchmark for systematic R&D with specific capacities above 150 mA h g −1 even at 40 °C.
This study sought to assess the impact of right ventricular dysfunction (RVD) as defined by impaired right ventricular-to-pulmonary artery (RV-PA) coupling, on survival after edge-to-edge ...transcatheter mitral valve repair (TMVR) for severe secondary mitral regurgitation (SMR).
Conflicting data exist regarding the benefit of TMVR in severe SMR. A possible explanation could be differences in RVD.
Using data from the EuroSMR (European Registry on Outcomes in Secondary Mitral Regurgitation) registry, this study compared the characteristics and outcomes of SMR patients undergoing TMVR, according to their RV-PA coupling, assessed by tricuspid annular plane systolic excursion-to-systolic pulmonary artery pressure (TAPSE/sPAP) ratio.
Overall, 817 patients with severe SMR and available RV-PA coupling assessment underwent TMVR in the participating centers. RVD was present in 211 patients (25.8% with a TAPSE/sPAP ratio <0.274 mm/mm Hg). Although all patients demonstrated significant improvement in their New York Heart Association (NYHA) functional class, there was a trend toward a lower rate of NYHA functional class I or II among patients with RVD (56.5% vs. 65.5%, respectively; p = 0.086) after TMVR. Survival rates at 1 and 2 years were lower among patients with RVD (70.2% vs. 84.0%, respectively; p < 0.001; and 53.4% vs. 73.1%, respectively; p < 0.001). On multivariate analysis, a reduced TAPSE/sPAP ratio was a strong predictor of mortality (odds ratio: 1.62; 95% confidence interval: 1.14 to 2.31; p = 0.007).
RVD, as shown by impairment of RV-PA coupling, is a major predictor of adverse outcome in patients undergoing TMVR for severe SMR. The often neglected functional and anatomic RV parameters should be systematically assessed when planning TMVR procedures for patients with severe SMR.
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The here shown data support the article “The Sand Equation and its Enormous Practical Relevance for Solid-State Lithium Metal Batteries”. 1 In this data set, all cells include the poly (ethylene ...oxide)-based solid polymer electrolyte (PEO-based SPE). The behaviour in symmetric Li||Li cells are provided in a three-electrode cell setup, thus with the use of a reference electrode. Moreover, the Sand behaviour is reported for varied negative electrodes with the focus on polarization onset, defined as transition time. The data of the electrochemical response after the variation of additional parameter, i.e. SPE thicknesses, are shown, as well. The theoretical Sand equation is linked with practically obtained values also for varied Li salt concentration. Finally, the discharge behaviour is provided including further charge/discharge cycles with the use of LiNi0.6Mn0.2Co0.2O2 (NMC622) as active material for positive electrodes.
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