Surface-localized phase mediation accelerates quasi-solid-state reaction kinetics in sulfur batteries
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Improving lithium-sulfur battery performance using a polysaccharide binder derived from red algae
Li-S batteries are a promising energy storage technology due to their high theoretical capacity, but they suffer from issues such as poor cycle stability and capacity loss over time. Here, we investigate the impact of carrageenan, a polysaccharide binder derived from red algae, on the performance of Li-S batteries. Electrode slurries are prepared without the toxic solvent N-methyl-2-pyrrolidone, using only water as a solvent and dispersant, making the process potentially scalable and cost-effective. With the optimal amount of carrageenan, we observe a capacity retention of 69.1% at 4 C after 1000 charge-discharge cycles. Carrageenan-based electrodes deliver 30% higher capacity than those made with the industry-standard polyvinylidene fluoride binder. X-ray photoelectron spectroscopy analysis confirms the chemical binding of carrageenan to the sulfur active material, and transmission X-ray absorption spectroscopy reveals that carrageenan effectively traps shorter-chain lithium polysulfides, improving the overall battery performance.
Escalation of caldera unrest indicated by increasing emission of isotopically light sulfur
Calderas are depressions formed by some of the largest volcanic eruptions. Their long-lived inter-eruptive periods are occasionally interrupted by phases of unrest, in which escalating seismicity, ground deformation and gas emissions raise concerns of potential volcano reawakening. However, interpretation of such physico-chemical signals is complicated by few examples of monitored unrest that culminated into eruption and by our fragmentary understanding of the drivers and timescales of caldera reactivation. Here we show that multi-decadal gas observations at the restless Campi Flegrei caldera in Italy record an unprecedented increase in isotopically light sulfur release from fumaroles since 2018. We then use hydrothermal gas equilibria and numerical simulations of magmatic degassing to propose that such a change in sulfur emissions results from decompression-driven degassing of mafic magma at ≥6 km depth, along with some extent of sulfur remobilization from hydrothermal minerals. Examination of a global dataset indicates that, despite the diversity in eruptive behaviour and tectonic setting, increasing sulfur output may be a common process during unrest escalation at calderas generally. Hence, our observations and models of sulfur behaviour may inform interpretations of unrest and hazard assessment at reawakening calderas and hydrothermal active volcanoes worldwide.
The evolution of lithium-ion battery recycling
Demand for lithium-ion batteries (LIBs) is increasing owing to the expanding use of electrical vehicles and stationary energy storage. Efficient and closed-loop battery recycling strategies are therefore needed, which will require recovering materials from spent LIBs and reintegrating them into new batteries. In this Review, we outline the current state of LIB recycling, evaluating industrial and developing technologies. Among industrial technologies, pyrometallurgy can be broadly applied to diverse electrode materials but requires operating temperatures of over 1,000 °C and therefore has high energy consumption. Hydrometallurgy can be performed at temperatures below 200 °C and has material recovery rates of up to 93% for lithium, nickel and cobalt, but it produces large amounts of wastewater. Developing technologies such as direct recycling and upcycling aim to increase the efficiency of LIB recycling and rely on improved pretreatment processes with automated disassembly and cleaner mechanical separation. Additionally, the range of materials recovered from spent LIBs is expanding from the cathode materials recycled with established methods to include anode materials, electrolytes, binders, separators and current collectors. Achieving an efficient recycling ecosystem will require collaboration between recyclers, battery manufacturers and electric vehicle manufacturers to aid the design and automation of battery disassembly lines.
Elastic trapping by acoustoelastically induced transparency
Elastic bound states in the continuum (BICs) have recently attracted significant interests due to their exceptionally high-Q-factor, which enables the confined mode to be completely decoupled from spectrally coexisting radiative channels. We report on the emergence of a state that induces a slow vibration phenomenon, which exhibits a multiphysics analogy to the notion of slow light observed in electromagnetically induced transparency (EIT). Such a state can be achieved through the interaction of acoustoelastic coupling. Our proposed design involves a composite with two acoustic cavities encased in an elastic bar, making quasi-BICs feasible with high spatial efficiency in a localized area while allowing for the tunability of the Purcell factor by around six orders of magnitude. The observation of quasi-BICs with acoustoelastically induced transparency (AEIT) lineshapes, which are manifested by the coupling of two disparate physics domains, will expand the BIC family and enable applications in areas such as lasing, sensing, screening, and energy storage platforms where ultrahigh-Q-factor modes and radiative channels coexist.
Dynamic effects of psychiatric vulnerability, loneliness and isolation on distress during the first year of the COVID-19 pandemic
The COVID-19 pandemic’s impact on mental health is challenging to quantify because pre-existing risk, disease burden and public policy varied across individuals, time and regions. Longitudinal, within-person analyses can determine whether pandemic-related changes in social isolation impacted mental health. We analyzed time-varying associations between psychiatric vulnerability, loneliness, psychological distress and social distancing in a US-based study during the first year of the pandemic. We surveyed 3,655 participants about psychological health and COVID-19-related circumstances every 2 weeks for 6 months. We combined self-reports with regional social distancing estimates and a classifier that predicted probability of psychiatric diagnosis at enrollment. Loneliness and psychiatric vulnerability both impacted psychological distress. Loneliness and distress were also linked to social isolation and stress associated with distancing, and psychiatric vulnerability shaped how regional distancing affected loneliness across time. Public health policies should address loneliness when encouraging social distancing, particularly in those at risk for psychiatric conditions.
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