Aqueous Zn‐metal batteries are the most promising system for large‐scale energy storage due to their high capacity, high safety, and low cost. The Zn‐metal anode, however, suffers from continuous ...parasitic reactions, random dendrite growth, and sluggish kinetics in aqueous electrolytes. Herein, a high donor number solvent, tetramethylurea (TMU), is introduced as electrolyte additive to enable highly reversible Zn‐metal anode, where the TMU can 1) preferentially adsorb on the Zn surface to inhibit Zn corrosion and suppress parasitic reaction, 2) solvate with Zn2+ and exclude the H2O from Zn2+ solvation sheath to weaken water activity significantly, and 3) contribute to form an inorganic‐organic bilayer solid electrolyte interphase to enable homogeneous and rapid Zn2+ transport kinetic for dendrite‐free Zn deposition. Benefiting from these three merits, the resulting aqueous electrolyte demonstrates a highly reversible Zn plating/stripping cycling in a Zn||Ti asymmetric cell for over 1200 cycles and in a Zn||Zn symmetric cell for over 4000 h. As a proof‐of‐concept, the aqueous Zn‐metal full cells assembled with various state‐of‐the‐art cathodes also deliver excellent cycling performance even with a 10 µm thin Zn anode, favoring the practical application.
A high donor solvent, tetramethylurea, is introduced as an electrolyte additive to enable highly reversible Zn‐metal anode with superior cyclability under harsh conditions. Rationally, the tetramethylurea can adsorb on the Zn surface to suppress parasitic reaction, solvate with Zn2+ to weaken water activity, and contribute to form an inorganic‐organic bilayer solid electrolyte interphase to enable homogeneous Zn deposition and rapid Zn2+ transport kinetic.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
As hot topics in the chemical conversion of CO2, the photo‐/electrocatalytic reduction of CO2 and use of CO2 as a supporter for energy storage have shown great potential for the utilization of CO2. ...However, many obstacles still exist on the road to realizing highly efficient chemical CO2 conversion, such as inefficient uptake/activation of CO2 and mass transport in catalysts. Covalent organic frameworks (COFs), as a kind of porous material, have been widely explored as catalysts for the chemical conversion of CO2 owing to their unique features. In particular, COF‐based functional materials containing diverse active sites (such as single metal sites, metal nanoparticles, and metal oxides) offer great potential for realizing CO2 conversion and energy storage. This Minireview discusses recent breakthroughs in the basic knowledge, mechanisms, and pathways of chemical CO2 conversion strategies that use COF‐based functional catalysts. In addition, the challenges and prospects of COF‐based functional catalysts for the efficient utilization of CO2 are also introduced.
This Minireview discusses recent developments in the basic knowledge, mechanisms, and CO2 utilization strategies regarding the use of functional materials based on covalent‐organic frameworks (COFs) with diverse active sites as catalysts. Insight is provided into the challenges and prospects of COF‐based catalysts for the design of the next‐generation photo‐/electrocatalysts for the utilization of CO2.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
We identify the impact of expansionary monetary policy in China during the 2008–2009 global financial crisis on the credit and investment allocation among firms. We obtain robust evidence that ...expansionary monetary policy led to the misallocation of bank credit to less productive firms after controlling for confounding factors. However, we find that investment increased more for more productive firms. Additional analyses show that this occurred partly because more productive firms hoarded cash before the crisis, and partly because less productive firms invested more in financial assets.
•Expansionary monetary policy led to the allocation of bank credits to less productive Chinese firms.•The investment increased more for more productive firms in respond to the expansionary monetary policy.•Additional analyses showed that this is partly because less productive firms invest more in financial assets.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lithium metal batteries hold great promise for promoting energy density and operating at low temperatures, yet they still suffer from insufficient Li compatibility and slow kinetic, especially at ...ultra‐low temperatures. Herein, we rationally design and synthesize a new amphiphilic solvent, 1,1,2,2‐tetrafluoro‐3‐methoxypropane, for use in battery electrolytes. The lithiophilic segment is readily to solvate Li+ to induce self‐assembly of the electrolyte solution to form a peculiar core‐shell‐solvation structure. Such unique solvation structure not only largely improves the ionic conductivity to allow fast Li+ transport and lower the desolvation energy to enable facile desolvation, but also leads to the formation of a highly robust and conductive inorganic SEI. The resulting electrolyte demonstrates high Li efficiency and superior cycling stability from room temperature to −40 °C at high current densities. Meanwhile, anode‐free high‐voltage cell retains 87 % capacity after 100 cycles.
A new amphiphilic solvent is rationally designed to induce self‐assembly of the electrolyte solution to form a peculiar core‐shell‐solvation structure. Such unique solvation structure bestows improved ionic conductivity, low desolvation energy, and highly robust and conductive SEI, which overcomes the long‐standing Li compatibility and deposition kinetic challenges, enabling the stable operation of Li‐metal battery under ultra‐low temperature.
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The precise tuning and multi‐dimensional processing of covalent organic frameworks (COFs)‐based materials into multicomponent superstructures with appropriate diversity are essential to maximize ...their advantages in catalytic reactions. However, up to now, it remains an ongoing challenge for the precise design of COFs‐based multicomponent nanocomposites with diverse architectures. Herein, a metal organic framework (MOF)‐sacrificed in situ acid‐etching (MSISAE) strategy that enables continuous synthesis of core‐shell, yolk‐shell, and hollow‐sphere COFs‐based nanocomposites through tuning of core decomposition (NH2‐MIL‐125 into TiO2) rate is developed. More importantly, due to the multiple active sites, fast transfer of carriers, increased light utilization ability, et al, one of the obtained samples, NH2‐MIL‐125/TiO2@COF‐366‐Ni‐OH‐HAc (yolk‐shell) with special three components, exhibits high photocatalytic CO2‐to‐CO conversion efficiency in the gas‐solid mode. The MSISAE strategy developed in this work achieves the precise morphology design and control of multicomponent hybrid composites based on COFs, which may pave a new way in devealoping porous crystalline materials with powerful superstructures for multifunctional catalytic reactions.
A metal–organic‐framework‐sacrificed in situ acid‐etching strategy to bring about the controllable synthesis of a series of covalent organic framework based multicomponent nanocomposites from core–shell, yolk–shell, and hollow‐sphere structures is presented. Combining the unique yolk–shell structure with the synergistic effects of the three components, the MTCN‐H (ys) demon strates remarkable catalytic performance in photocatalytic reduction of CO2 with H2O.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
In this letter, we study the deep reinforcement learning (DRL)-based routing, modulation and spectrum assignment problem in the elastic optical networks. We emphasize the importance of proper reward ...design of the DRL framework and we propose to include some heuristic information to the reward design. This introduction of human knowledge to the machine learning, is to reduce the exploration blindness of the latter and lead to more efficient learning of better policies. We make it clear that what kind of heuristic information should be included in the reward design is an open question. Specifically, we propose to consider the spectrum fragmentation level of each candidate path as the heuristic information. As a result, the DRL agent is more inclined to choose the candidate path that leads to lower spectrum fragmentation level, which is more friendly for future traffic requests. Simulation results show that the proposed heuristic reward design scheme outperforms both the simple-reward DRL based approaches and the heuristic rule-based approaches.
Si microparticle (SiMP) anodes feature much lower production cost and higher tap density compared to their nanosized counterparts, which hold great promise for high‐energy‐density lithium‐ion ...batteries, yet they suffer from unavoidable particle pulverization during repeated cycling, thus making their practical application extremely challenging. Herein, a non‐flammable localized high‐concentration electrolyte (LHCE) is rationally formulated using a fluorinated solvent, 2,2,2‐trifluoroethyl methyl carbonate (FEMC), to induce fluorinated solvent‐coupled anion‐derived interfacial chemistry. Unlike other LHCEs, the FEMC‐based LHCE is demonstrated to build a highly robust and stable F‐rich inorganic–organic bilayer solid–electrolyte interphase on SiMP anode, which endows stable cycling of SiMP anode (≈3.4 mAh cm−2) with an ultrahigh Coulombic efficiency of ≈99.7%. Coupled with its high anodic stability, the FEMC‐based LHCE endows unprecedented cycling stability for high‐energy‐density batteries containing high‐capacity SiMP anodes with Ni‐rich LiNi8Mn1Co1O2 or 5 V‐class LiNi0.5Mn1.5O4 cathodes. Remarkably, a 1.0 Ah‐level SiMP||LiNi8Mn1Co1O2 pouch‐cell stably operates for more than 200 cycles, representing the pioneering report in pouch cells containing SiMP anodes.
A fluorinated solvent is incorporated into localized high‐concentration electrolyte to induce fluorinated solvent‐coupled anion‐derived interfacial chemistry, which yields a highly robust and stable F‐rich inorganic–organic bilayer solid–electrolyte interphase to enable stable cycling of Si microparticle anode. This electrolyte overcomes the longstanding challenges of Si microparticle pulverization and high‐voltage incompatibility, endowing the stable operation of high‐energy‐density Li‐ion batteries.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
To improve the network scalability, a large elastic optical network is typically segmented into multiple autonomous domains, where each domain possesses high autonomy and privacy. This architecture ...is referred to as the multi-domain elastic optical network (MDEON). In the MDEON, the routing, modulation, and spectrum allocation (RMSA) for the inter-domain service requests are challenging. As a result, deep reinforcement learning (DRL) has been introduced recently where the RMSA policies are learned during the interaction of the DRL agents with the MDEON environment. Due to the autonomy of each domain in the MDEON, joint RMSA is essential to improve the overall performance. To realize the joint RMSA, we propose a hierarchical reinforcement learning (HRL) framework which consists of a high-level DRL module and multiple low-level DRL modules (one for each domain), with the collaboration of DRL modules. More specifically, for the inter-domain service requests, the high-level module obtains some abstracted information from the low-level DRL modules and generates the inter-domain RMSA decision for the low-level modules. Then the low-level DRL module gives the intra-domain RMSA decision and feeds back to the high-level module. The proposed HRL framework preserves the autonomy of each single domain while delivering effective overall network performance through the cooperation of the high-level and low-level DRL modules. Simulation results demonstrate that our proposed method outperforms previous approaches.
Age-related macular degeneration (AMD) is a serious blinding eye disease. Previous neuroimaging studies reported that AMD were accompanied by abnormalities of the brain. However, whether AMD patients ...were associated with functional connectivity strength (FCS) or not remains unknown. In our study, the purpose of the study was to assess FCS changes in AMD patients.
In our study, 20 AMD patients and 20 healthy controls (HCs), matched closely by sex, age, and educational level were underwent MRI scanning. FCS method and seed-based functional connectivity (FC) method were applied to investigate the functional network changes between two groups. Moreover, support vector machine (SVM) method was applied to assess the FCS maps as a feature to classification of AMD diseases.
Our study reported that AMD patients showed decreased FCS values in the bilateral calcarine, left supplementary motor area, left superior parietal lobule and left paracentral lobule (ParaL) relative to the HC group. Meanwhile, our study found that the AMD patients showed abnormal FC within visual network, sensorimotor network and default mode network. Moreover, the SVM method showed that FCS maps as machine learning features shows good classification efficiency (area under curve = 0.82) in the study.
Our study demonstrated that AMD patients showed abnormal FCS with the visual network, sensorimotor network and default mode network, which might reflect the impaired vision, cognition and motor function in AMD patients. In addition, FCS indicator can be used as an effective biological marker to assist the clinical diagnosis of AMD.
Metal-organic framework (MOF)-derived hybrids are promising electrode materials in electrochemical energy storage, owing to their high surface area that offers enormous redox sites and excellent ...conductivity. In this work, MOF-derived cerium oxide/carbon integrated with molybdenum disulfide (CeO2/C/MoS2) hybrid is developed as an electrode material for supercapacitor. Remarkably, integration of CeO2/C with small amount of MoS2 has considerably enhanced the electrochemical performance. Moreover, CeO2/C/MoS2 hybrid exhibited both surface and diffusion-controlled mechanism towards charge storage. The CeO2/C/MoS2 hybrid showed an outstanding specific capacitance (specific capacity) of 1325.67 F g−1 (397.70 C g−1) and excellent cyclic stability with capacitance retention of 92.8% after 1000 charging-discharging cycles, which is significantly higher than that of CeO2/C (727.49 F g−1) or else that of MoS2 (300.33 F g−1) at 1 A g−1. In addition, asymmetric supercapacitor (ASC) fabricated with CeO2/C/MoS2 hybrid and activated carbon (AC) showed remarkable electrochemical performance with high specific capacitance (110.55 F g−1), excellent cyclic stability (even after 1000 cycles) and high energy density of 34.55 Wh kg−1 at a power density of 666.7 W kg−1. Thus, MOF derived CeO2/C integrated MoS2 hybrid is a potential electrode material for the ASCs.
MOF-derived CeO2/C integrated MoS2 (CeO2/C/MoS2) hybrid is developed as an electrode material with high-performance for asymmetric supercapacitor. Display omitted
•MOF-derived CeO2/C integrated MoS2 hybrid is prepared.•The charge storage mechanism for a hybrid electrode is investigated.•CeO2/C/MoS2 electrode exhibits specific capacitance of 1325.67 F g−1 at 1 A g −1.•The ASC exhibits an excellent energy density of 34.55 W h kg−1 at 666.7 W kg−1.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
