The aim of the paper is to present a promising approach for recycling high value-added metals from the cathode materials of spent LIBs. The synthesis process of NCM cathode material enlightened us to ...apply reduction roasting to break LiNixCoyMnzO2 into simple compounds or metals. Accordingly, the effect of several factors such as temperature, carbon dosage and roasting time is assessed on the leaching efficiency of valuable metals. The roasted products are analyzed by XRD and SEM-EDS, and the results show that the cathode material after reduction roasting is primarily transformed into Li2CO3, Ni, Co and MnO. However, the solubility of Li2CO3 is relatively low, so carbonated water leaching is used to treat the roasted products. Then the filtrate is evaporated for the preparation of pure Li2CO3, and residue is leached to recycle other metals with H2SO4. The results indicate that, after roasted at 650 °C for 3 h with 19.9% carbon dosage, 84.7% Li is preferentially recovered via carbonated water leaching, and more than 99% Ni, Co and Mn are recycled via acid leaching without adding reductant. Finally, the products of Li2CO3, NiSO4, CoSO4 and MnSO4 are obtained. The process have great potential for industrial-scale recycling from spent LIBs.
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•A simple and efficient process is proposed for recovering spent LIBs.•LiNixCoyMnzO2 was transformed into Li2CO3, Ni, Co and MnO by reduction roasting.•Carbonated water leaching was used to selectively recover Li from roasted products.•Co, Ni and Mn were efficiently leached by H2SO4 solution without adding reductant.•The products of Li2CO3, NiSO4, CoSO4 and MnSO4 were obtained.
A combined process was presented to recover valuable metals from lithium nickel cobalt manganese (NCM) cathodes of spent lithium-ion batteries. In this process, the cathode scrap was first roasted ...with carbonaceous reductant, and then carbonation water leaching was employed to selectively extract Li from the roasted cathodes. Finally, the obtained residue was leached in sulfuric acid solution to recover Co, Ni and Mn. A systematic investigation combining thermodynamic analysis, leaching experiments and characterization was conducted to explore the effect of operating conditions and leaching mechanism. The results indicate that the leaching of Li is significantly improved by injecting of CO2 into the leaching system, and more than 80% of Li can be leached within 10 min at a low liquid-solid ratio. High-quality Li2CO3 can be prepared from the leachate by direct evaporation. More than 96% of Ni, Co and Mn are extracted without adding reductant under the conditions of a H2SO4 dosage of 1.15 times the theoretical value, a time of 2.5 h, a temperature of 55 °C and a liquid-solid ratio of 3.5 mL g−1. The acid leaching process is more efficient and economical, which is ascribed to the transformation of the low-valence states of metals with high activity after reduction roasting.
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•An efficient and economical process was proposed for recovering spent LIBs.•Over 85% of Li was selectively extracted at a low L/S ratio by carbonation leaching.•High-quality Li2CO3 was prepared via direct evaporation of carbonation leachate.•More than 98% of Ni, Mn and 96% of Co were leached without adding reductant.•Leaching mechanism of Co, Ni and Mn was explained by thermodynamic calculation.
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•The formation of water-insoluble LiAlO2 led to a decrease in the Li leaching.•About 88% of Li was preferentially extracted by carbonation water leaching.•More than 98% of Ni, Co and ...Mn were acid-leached without reducing agent.•Battery-grade Li2CO3 was prepared via direct evaporation of carbonation leachate.•A preliminary economic analysis of proposed process was performed.
Recycling of spent lithium-ion batteries becomes increasingly important due to the presence of valuable metals and great harm to the environment. In this work, a combined method of reduction roasting with methane, carbonation water leaching and acid leaching was proposed to recover valuable metals from spent lithium-ion batteries. Firstly, thermodynamic analysis was applied to predict the reaction products after reduction roasting. It indicates that the presence of Al will lead to the formation of water-insoluble LiAlO2. Then, pre-alkali leaching was used to preferentially separate Al to facilitate the Li leaching. The effects of roasting temperature, time and methane flow rate on reduction roasting have been further studied. The results show that under the optimal roasting conditions (temperature: 600 °C, time: 30 min, methane flow rate: 300 mL/min), about 88% of Li can be preferentially extracted and over 98% of Mn, Ni and Co are subsequently acid-leached without the employment of reducing agent. Additionally, the removal of organic matters during the roasting process decreases the concentration of F, P and COD in the leachate and further reduces the cost of wastewater treatment. Finally, the preliminary economic analysis of proposed process confirms that the process has high potential for the industrial production.
Governments worldwide are implementing mass vaccination programs in an effort to end the novel coronavirus (COVID-19) pandemic. Here, we evaluated the effectiveness of the COVID-19 vaccination ...program in its early stage and predicted the path to herd immunity in the U.S. By early March 2021, we estimated that vaccination reduced the total number of new cases by 4.4 million (from 33.0 to 28.6 million), prevented approximately 0.12 million hospitalizations (from 0.89 to 0.78 million), and decreased the population infection rate by 1.34 percentage points (from 10.10 to 8.76%). We built a Susceptible-Infected-Recovered (SIR) model with vaccination to predict herd immunity, following the trends from the early-stage vaccination program. Herd immunity could be achieved earlier with a faster vaccination pace, lower vaccine hesitancy, and higher vaccine effectiveness. The Delta variant has substantially postponed the predicted herd immunity date, through a combination of reduced vaccine effectiveness, lowered recovery rate, and increased infection and death rates. These findings improve our understanding of the COVID-19 vaccination and can inform future public health policies.
Until now there has been no fundamental theory applicable for biodegradable metals (BMs). First, this paper optimizes the definition of BMs given in 2014. Second, the dual criteria of ...biodegradability and biocompatibility are proposed for BMs, and all metallic elements in the periodic table with accessible data are screened on the basis of these criteria. Regarding biodegradability, electrode potential, reactivity series, galvanic series, Pilling–Bedworth ratio, and Pourbaix diagrams are all adopted as parameters to classify the degradable and nondegradable nature of a material, especially in a physiological environment. Considering the biocompatibility at different levels, cellular biocompatibility, tissue biocompatibility, and human/clinical related biocompatibility parameters are put forward to comprehensively evaluate the biosafety of BMs. Third, for the material design of BMs, mechanical properties, chemical properties, physical properties and biological properties should be considered and balanced to guarantee that the degradation behavior of BMs match well with a tissue regeneration/repair procedure as the function of time and spatial location. Besides the selected metallic elements, some nonmetallic elements are selected as suitable alloying elements for BMs. Finally, five classification/research directions for future BMs are proposed: biodegradable pure metals, crystalline alloys, bulk metallic glasses, high entropy alloys, and metal matrix composites.
The fundamental theory of biodegradable metals are clarified in this review article, with the definition of biodegradable metals, biodegradability, and biocompatibility dual criteria for metallic elements in the periodic table being regarded as biodegradable metals. Key properties needed to be considered for materials design of biodegradable metals and future research and development directions for biodegradable metals are proposed.
Grain size effects on the physical properties of polycrystalline ferroelectrics have been extensively studied for decades; however there are still major controversies regarding the dependence of the ...piezoelectric and ferroelectric properties on the grain size. Dense BaTiO3 ceramics with different grain sizes were fabricated by either conventional sintering or spark plasma sintering using micro- and nano-sized powders. The results show that the grain size effect on the dielectric permittivity is nearly independent of the sintering method and starting powder used. A peak in the permittivity is observed in all the ceramics with a grain size near 1 μm and can be attributed to a maximum domain wall density and mobility. The piezoelectric coefficient d33 and remnant polarization Pr show diverse grain size effects depending on the particle size of the starting powder and sintering temperature. This suggests that besides domain wall density, other factors such as back fields and point defects, which influence the domain wall mobility, could be responsible for the different grain size dependence observed in the dielectric and piezoelectric/ferroelectric properties. In cases where point defects are not the dominant contributor, the piezoelectric constant d33 and the remnant polarization Pr increase with increasing grain size.
Inspired by the process of "metallurgy first and then beneficiation" for disposing low-grade and complex mineral resources, we proposed a breakthrough method to recover valuable metals from spent ...entire lithium-ion batteries that experienced only discharge and simple cut, removing the pre-sorting process, which is an inevitable but problematic process in the commonly used hydrometallurgical method. Reduction roasting was first conducted to directly treat spent entire LIBs, and the cathode materials are dissociated and transformed to simple substances. Moreover, the harmful electrolytes, binder and membrane are decomposed into the gas, and can be disposed by the well-established, widely used technology. Over 81% of Li can be preferentially extracted from the roasted products by carbonation water leaching. In addition, more than 95% of Ni, Co and Cu can be leached by additional oxidation ammonia leaching, while Mn in the ammonia leaching residue can be recovered
via
beneficiation process. Finally, the ammonia solution can be reused after the recovery of valuable metals. Overall, this new recycling method with advantages of high metal recovery efficiency, easily accessible equipment and environmental friendliness can meet the requirements of green chemistry, and has great potential in industrial production.
We proposed a breakthrough method for the recycling of spent lithium-ion batteries without pre-sorting, which has the great advantages of high metal recovery efficiency, easily accessible equipment, and environmental friendliness.
The optical chirality induced at the absorption bands due to electronic exciton coupling of the transition dipole moments between chromophores in close proximity is ubiquitous in helical organic ...materials. However, inorganic materials with optical activity resulting from electronic transitions have not been explored. Here we report the synthesis of chiral TiO 2 fibres via transcription of the helical structure of amino acid-derived amphiphile fibres through coordination bonding interactions between the organics and the TiO 2 source. Upon calcination, the as-prepared amorphous TiO 2 double-helical fibres with a pitch length of ~100 nm were converted to double-helical crystalline fibres with stacks of anatase nanocrystals in an epitaxial helical relationship. Both the amorphous and anatase crystalline helical TiO 2 fibres exhibited optical response to circularly polarized light at the absorption edge around ~350 nm. This was attributed to the semiconductor TiO 2 -based electronic transitions from the valence band to the conduction band under an asymmetric electric field.
Adiponectin is an abundant adipokine with pleiotropic protective effects against a cluster of obesity-related cardiometabolic disorders. However, its role in adaptive thermogenesis has scarcely been ...explored. Here we showed that chronic cold exposure led to a markedly elevated production of adiponectin in adipocytes of subcutaneous white adipose tissue (scWAT), which in turn bound to M2 macrophages in the stromal vascular fraction. Chronic cold exposure-induced accumulation of M2 macrophages, activation of beige cells, and thermogenic program were markedly impaired in scWAT of adiponectin knockout (ADN KO) mice, whereas these impairments were reversed by replenishment with adiponectin. Mechanistically, adiponectin was recruited to the cell surface of M2 macrophages via its binding partner T-cadherin and promoted the cell proliferation by activation of Akt, consequently leading to beige cell activation. These findings uncover adiponectin as a key efferent signal for cold-induced adaptive thermogenesis by mediating the crosstalk between adipocytes and M2 macrophages in scWAT.
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•Cold exposure selectively induces adiponectin accumulation in subcutaneous WAT•Adiponectin KO mice are resistant to subcutaneous adipose browning during cold adaptation•Cold-induced M2 macrophage proliferation requires adiponectin in subcutaneous WAT•T-cadherin serves as an anchor for tethering of adiponectin to M2 macrophages
Adiponectin protects against a cluster of obesity-related metabolic complications through multiple mechanisms. This study shows that chronic cold exposure induces adiponectin accumulation in subcutaneous fat, which is indispensable for subcutaneous adipose browning via promoting M2 macrophage proliferation. These findings suggest a key role of adiponectin in mediating crosstalk between innate immunity and adaptive thermogenesis.
This paper introduces a simple but effective image filtering method, namely, local adaptive image filtering (LAIF), based on an image segmentation method, i.e., recursive dilation segmentation (RDS). ...The algorithm is motivated by the observation that for the pixel to be smoothed, only the similar pixels nearby are utilized to obtain the filtering result. Relying on this observation, similar pixels are partitioned by RDS before applying a locally adaptive filter to smooth the image. More specifically, by directly taking the spatial information between adjacent pixels into consideration in a recursive dilation way, RDS is firstly proposed to partition the guided image into several regions, so that the pixels belonging to the same segmentation region share a similar property. Then, guided by the iterative segmented results, the input image can be easily filtered via a local adaptive filtering technique, which smooths each pixel by selectively averaging its local similar pixels. It is worth mentioning that RDS makes full use of multiple integrated information including pixel intensity, hue information, and especially spatial adjacent information, leading to more robust filtering results. In addition, the application of LAIF in the remote sensing field has achieved outstanding results, specifically in areas such as image dehazing, denoising, enhancement, and edge preservation, among others. Experimental results show that the proposed LAIF can be successfully applied to various filtering-based tasks with favorable performance against state-of-the-art methods.
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