Continuous carbon capture in an electrochemical solid-electrolyte reactor.

Electrochemical carbon-capture technologies, with renewable electricity as the energy input, are promising for carbon management but still suffer from low capture rates, oxygen sensitivity or system complexity1-6. Here we demonstrate a continuous electrochemical carbon-capture design by coupling oxygen/water (O2/H2O) redox couple with a modular solid-electrolyte reactor7. By performing oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) redox electrolysis, our device can efficiently absorb dilute carbon dioxide (CO2) molecules at the high-alkaline cathode-membrane interface to form carbonate ions, followed by a neutralization process through the proton flux from the anode to continuously output a high-purity (>99%) CO2 stream from the middle solid-electrolyte layer. No chemical inputs were needed nor side products generated during the whole carbon absorption/release process. High carbon-capture rates (440 mA cm-2, 0.137 mmolCO2 min-1 cm-2 or 86.7 kgCO2 day-1 m-2), high Faradaic efficiencies (>90% based on carbonate), high carbon-removal efficiency (>98%) in simulated flue gas and low energy consumption (starting from about 150 kJ per molCO2) were demonstrated in our carbon-capture solid-electrolyte reactor, suggesting promising practical applications.

Constrained C2 adsorbate orientation enables CO-to-acetate electroreduction.

The carbon dioxide and carbon monoxide electroreduction reactions, when powered using low-carbon electricity, offer pathways to the decarbonization of chemical manufacture1,2. Copper (Cu) is relied on today for carbon-carbon coupling, in which it produces mixtures of more than ten C2+ chemicals3-6: a long-standing challenge lies in achieving selectivity to a single principal C2+ product7-9. Acetate is one such C2 compound on the path to the large but fossil-derived acetic acid market. Here we pursued dispersing a low concentration of Cu atoms in a host metal to favour the stabilization of ketenes10-chemical intermediates that are bound in monodentate fashion to the electrocatalyst. We synthesize Cu-in-Ag dilute (about 1 atomic per cent of Cu) alloy materials that we find to be highly selective for acetate electrosynthesis from CO at high *CO coverage, implemented at 10 atm pressure. Operando X-ray absorption spectroscopy indicates in situ-generated Cu clusters consisting of <4 atoms as active sites. We report a 12:1 ratio, an order of magnitude increase compared to the best previous reports, in the selectivity for acetate relative to all other products observed from the carbon monoxide electroreduction reaction. Combining catalyst design and reactor engineering, we achieve a CO-to-acetate Faradaic efficiency of 91% and report a Faradaic efficiency of 85% with an 820-h operating time. High selectivity benefits energy efficiency and downstream separation across all carbon-based electrochemical transformations, highlighting the importance of maximizing the Faradaic efficiency towards a single C2+ product11.

Dynamic Phase Transformations of Prussian Blue Analogue Crystals in Hydrotherms.

Prussian blue analogue (PBA)/metal-organic frameworks (MOFs) are multifunctional precursors for the synthesis of metal/metal compounds, carbon, and their derived composites (P/MDCs) in chemical, medical, energy, and other applications. P/MDCs combine the advantages of both the high specific surface area of PBA/MOF and the electronic conductivity of metal compound/carbon. Although the calcination under different atmospheres has been extensively studied, the transformation mechanism of PBA/MOF under hydrothermal conditions remains unclear. The qualitative preparation of P/MDCs in hydrothermal conditions remains a challenge. Here, we select PBA to construct a machine-learning model and measure its hydrothermal phase diagram. The architecture-activity relationship of substances among nine parameters was analyzed for the hydrothermal phase transformation of PBA. Excitingly, we established a universal qualitative model to accurately fabricate 31 PBA derivates. Additionally, we performed three-dimensional reconstructed transmission electron microscopy, X-ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy, in situ X-ray powder diffraction, and theoretical calculation to analyze the advantages of hydrothermal derivatives in the oxygen evolution reaction and clarify their reaction mechanisms. We uncover the unified principles of the hydrothermal phase transformation of PBA, and we expect to guide the design for a wide range of composites.

Ni3C/Ni3S2 Heterojunction Electrocatalyst for Efficient Methanol Oxidation via Dual Anion Co-modulation Strategy.

Enhancing active states on the catalyst surface by modulating the adsorption-desorption properties of reactant species is crucial to optimizing the electrocatalytic activity of transition metal-based nanostructured materials. In this work, an efficient optimization strategy is proposed by co-modulating the dual anions (C and S) in Ni3C/Ni3S2, the heterostructured electrocatalyst, which is prepared via a simple hot-injection method. The presence of Ni3C/Ni3S2 heterojunctions accelerates the charge carrier transfer and promotes the generation of active sites, enabling the heterostructured electrocatalyst to achieve current densities of 10/100 mA cm-2 at 1.37 V/1.53 V. The Faradaic efficiencies for formate production coupled with hydrogen evolution approach 100%, accompanied with a stability record of 350 h. Additionally, operando electrochemical impedance spectroscopy (EIS), in situ Raman spectroscopy, and density functional theory (DFT) calculations further demonstrate that the creation of Ni3C/Ni3S2 heterointerfaces originating from dual anions' (C and S) differentiation is effective in adjusting the d-band center of active Ni atoms, promoting the generation of active sites, as well as optimizing the adsorption and desorption of reaction intermediates. This dual anions co-modulation strategy to stable heterostructure provides a general route for constructing high-performance transition metal-based electrocatalysts.

Ambient Synthesis of Vanadium-based Prussian Blue Analogues Nanocubes for High-performance and Durable Aqueous Zinc-ion Batteries with Eutectic Electrolytes.

Prussian blue analogues (PBAs) have been widely studied in aqueous zinc-ion batteries (AZIBs) due to the characteristics of large specific surface area, open aperture, and straightforward synthesis. In this work, vanadium-based PBA nanocubes were firstly prepared using a mild in-situ conversion strategy at room temperature without the protection of noble gas. Benefiting from the multiple-redox active sites of V3+/V4+, V4+/V5+ and Fe2+/Fe3+, the cathode exhibited an excellent discharge specific capacity of 200 mA h g-1 in AZIBs, which is much higher than those of other metal-based PBAs nanocubes. To further improve the long-term cycling stability of the V-PBA cathode, a high concentration water-in-salt electrolyte (4.5 M ZnSO4 + 3 M Zn(OTf)2), and a water-based eutectic electrolyte (5.55 M glucose + 3 M Zn(OTf)2) were designed to successfully inhibit the dissolution of vanadium and improve the deposition of Zn2+ onto the zinc anode. More importantly, the assembled AZIBs maintained 55% of their highest discharge specific capacity even after 10000 cycles at 10 A g-1 with superior rate capability. This study provides a new strategy for the preparation of pure PBA nanostructures and a new direction for enhancing the long-term cycling stability of PBA-based AZIBs at high current densities for industrialization prospects.

Spiral-concave Prussian Blue Crystals with Rich Steps: Growth Mechanism and Coordination Regulation.

Investigating the formation and transformation mechanisms of spiral-concave crystals holds significant potential for advancing innovative material design and comprehension. We examined the kinetics-controlled nucleation and growth mechanisms of Prussian Blue crystals with spiral concave structures, and constructed a detailed crystal growth phase diagram. The spiral-concave hexacyanoferrate (SC-HCF) crystals, characterized by high-density surface steps and a low stress-strain architecture, exhibit enhanced activity due to their facile interaction with reactants. Notably, the coordination environment of SC-HCF can be precisely modulated by the introduction of diverse metals. Utilizing X-ray absorption fine structure spectroscopy and in-situ ultraviolet-visible spectroscopy, we elucidated the formation mechanism of SC-HCF to Co-HCF facilitated by oriented adsorption-ion exchange (OA-IE) process. Both experimental data, and density functional theory confirm that Co-HCF possesses an optimized energy band structure, capable of adjusting the local electronic environment and enhancing the performance of the oxygen evolution reaction. This work not only elucidates the formation mechanism and coordination regulation for rich steps HCF, but also offers a novel perspective for constructing nanocrystals with intricate spiral-concave structures.

Over 2 A cm-2 CO2 -to-Ethanol Conversion by Alkali-Metal Cation Induced Copper With Dominant (200) Facets.

The high-rate ethanol electrosynthesis from CO2 is challenging due to the low selectivity and poor activity, which requires the competition with other reduction products and H2 . Here, the electrochemical reconstruction of Cs3 Cu2 Cl5 perovskite to form surface Cl-bonded, low-coordinated Cs modified Cu(200) nanocubes (CuClCs), is demonstrated. Density functional theory calculations reveal that the CuClCs structure possesses low Bader charges and a large coordination capacity; and thus, can promote the CO2 -to-ethanol pathway via stabilizing C-O bond in oxygenate intermediates. The CuClCs catalyst exhibits outstanding partial current densities for producing ethanol (up to 2124 ± 54 mA cm-2 ) as one of the highest reported values in the electrochemical CO2 or CO reduction. This work suggests an attractive strategy with surface alkali-metal cations for ampere-level CO2 -to-ethanol electrosynthesis.

Organic Matter Counteracts the Enhancement of Cr(III) Extractability during the Fe(II)-Catalyzed Ferrihydrite Transformation: A Nanoscale- and Molecular-Level Investigation.

Phase transformation of ferrihydrite to more stable Fe (oxyhydr)oxides, catalyzed by iron(II) [Fe(II)], significantly influences the mobility of heavy metals [e.g., chromium (Cr)] associated with ferrihydrite. However, the impact of organic matter (OM) on the behavior of Cr(III) in the Fe(II)-catalyzed transformation of ferrihydrite and the underlying mechanisms are unclear. Here, the Fe(II)-catalyzed transformation of the coprecipitates of Fe(III), Cr(III), or rice straw-derived OM was studied at the nanoscale and molecular levels using Fe and Cr K-edge X-ray absorption spectroscopy and spherical aberration corrected scanning transmission electron microscopy (Cs-STEM). Batch extraction results suggested that the OM counteracted the enhancement of Cr(III) extractability during the Fe(II)-catalyzed transformation. Cs-STEM and XAS analysis suggested that Cr(III) could be incorporated into the goethite formed by Fe(II)-catalyzed ferrihydrite transformation, which, however, was inhibited by the OM. Furthermore, Cs-STEM analysis also provided direct nanoscale level evidence that residual ferrihydrite could re-immobilize the released Cr(III) during the Fe(II)-catalyzed transformation process. These results highlighted that the decreased extractability of Cr(III) mainly resulted from the inhibition of OM on the Fe(II)-catalyzed transformation of ferrihydrite to secondary Fe (oxyhydr)oxides, which facilitates insightful understanding and prediction of the geochemical cycling of Cr in soils with active redox dynamics.

Removal of CrO42-, a Nonradioactive Surrogate of 99TcO4-, Using LDH-Mo3S13 Nanosheets.

Removal of chromate (CrO42-) and pertechnetate (TcO4-) from the Hanford Low Activity Waste (LAW) is beneficial as it impacts the cost, life cycle, operational complexity of the Waste Treatment and Immobilization Plant (WTP), and integrity of vitrified glass for nuclear waste disposal. Here, we report the application of [MoIV3S13]2- intercalated layer double hydroxides (LDH-Mo3S13) for the removal of CrO42- as a surrogate for TcO4-, from ppm to ppb levels from water and a simulated LAW off-gas condensate of Hanford's WTP. LDH-Mo3S13 removes CrO42- from the LAW condensate stream, having a pH of 7.5, from ppm (∼9.086 × 104 ppb of Cr6+) to below 1 ppb levels with distribution constant (Kd) values of up to ∼107 mL/g. Analysis of postadsorbed solids indicates that CrO42- removal mainly proceeds by reduction of Cr6+ to Cr3+. This study sets the first example of a metal sulfide intercalated LDH for the removal of CrO42-, as relevant to TcO4-, from the simulated off-gas condensate streams of Hanford's LAW melter which contains highly concentrated competitive anions, namely F-, Cl-, CO32-, NO3-, BO33-, NO2-, SO42-, and B4O72-. LDH-Mo3S13's remarkable removal efficiency makes it a promising sorbent to remediate CrO42-/TcO4- from surface water and an off-gas condensate of nuclear waste.

Synthesis and characterization of a near-infrared persistent luminescent Cr-doped zinc gallate-calcium phosphate composite.

Near-infrared (NIR)-emitting persistent luminescence (PersL) nanoparticles have attracted great attention as a novel optical probe for bioimaging and biosensing applications. These nanoparticles emit long-lasting luminescence after the removal of the excitation source, which effectively eliminates the interference from tissue autofluorescence. Cr-doped zinc gallate (ZnGa2O4:Cr3+, CZGO) is a representative NIR-emitting PersL material. On the other hand, amorphous calcium phosphate (ACP) is a widely used drug carrier due to its high biocompatibility. In this work, we present a design of an ACP-based drug carrier with PersL properties, by forming a CZGO-ACP composite. The PersL properties of CZGO were preserved by composite formation, while it is found that the Zn2+ could migrate from CZGO to ACP during composite formation, leading to different luminescence mechanisms between pure CZGO and the CZGO-ACP composite. The electronic structure of the composite was analyzed by synchrotron X-ray absorption spectroscopy, and a structure-luminescence correlation was proposed.

Bias-Adaptable CO2-to-CO Conversion via Tuning the Binding of Competing Intermediates.

CO2 electroreduction powered by renewable electricity represents a promising method to enclose anthropogenic carbon cycle. Current catalysts display high selectivity toward the desired product only over a narrow potential window due primarily to unoptimized intermediate binding. Here, we report a functional ligand modification strategy in which palladium nanoparticles are encapsulated inside metal-organic frameworks with 2,2'-bipyridine organic linkers to tune intermediate binding and thus to sustain a highly selective CO2-to-CO conversion over widened potential window. The catalyst exhibits CO faradaic efficiency in excess of 80% over a potential window from -0.3 to -1.2 V and reaches the maxima of 98.2% at -0.8 V. Mechanistic studies show that the 2,2'-bipyridine on Pd surface reduces the binding strength of both *H and *CO, a too strong binding of which leads to competing formate production and CO poison, respectively, and thus enhances the selectivity and stability of CO product.

Cr cation-anchored carbon nanosheets: synthesis, paramagnetism and ferromagnetism.

Since the successfully synthesis of monolayer graphene, carbon-based materials have attracted wide and extensive attentions from researches. Due to the excellent transport capacity and conductivity, they are promising to be applied in electronic devices, even substituting the silicon-based electronic devices, optoelectronics and spintronics. Nevertheless, due to the non magnetic feature, many efforts have been devoted to endow carbon materials magnetism to apply them in the spintronic devices fabrication. Herein, a strategy of Cr cation solely anchored on two-dimensional carbon nanosheets by Cr-N bonds is developed, which introduces magnetism in carbon nanosheets. By extended x-ray absorption fine structure characterization, Cr cations are demonstrated to be atomically dispersed with Cr-N3coordination. And after Cr-N3anchored, carbon nanosheets exhibit ferromagnetic features with paramagnetic background. The magnetization varies with Cr content and reaches the maximum (Cr: 2.0%, 0.86 emu g-1) under 3 T at 50 K. The x-ray magnetic circular dichroism and first-principle calculations indicate that the magnetism is caused by the Cr3+component of the anchored Cr cations. This study sets a single cation anchoring carbon as a suitable candidate for future spintronics.

Protaetia brevitarsis larvae produce frass that can be used as an additive to immobilize Cd and improve fertility in alkaline soils.

Bioconversion of agricultural waste by Protaetia brevitarsis larvae (PBL) holds significant promise for producing high-quality frass organic amendments. However, the effects and mechanisms of PBL frass on Cd immobilization in an alkaline environment remain poorly understood. In this study, three types of frass, namely maize straw frass (MF), rice straw frass (RF), and sawdust frass (SF), were produced by feeding PBL. The Cd immobilization efficiencies of three frass in alkaline solutions and soils were investigated through batch sorption and incubation experiments, and spectroscopic techniques were employed to elucidate the sorption mechanisms of Cd onto different frass at the molecular level. The results showed that MF proved to be an efficient sorbent for Cd in alkaline solutions (176.67-227.27 mg g-1). X-ray absorption near-edge structure (XANES) spectroscopy indicated that Cd immobilization in frass is primarily attributed to the association with organic matter (OM-Cd, 78-90%). And MF had more oxygen-containing functional groups than the other frass. In weakly alkaline soils, MF application (0.5-1.5%) significantly decreased Cd bioavailability (5.65-18.48%) and concurrently improved soil nutrients (2.21-56.79%). Redundancy analysis (RDA) unveiled that pH, CEC, and available P were important factors controlling Cd fractions. Path analysis demonstrated that MF application affected Cd bioavailability directly and indirectly by influencing soil chemical properties and nutrients. In summary, MF, the product of PBL-mediated conversion maize straw, demonstrated promise as an effective organic amendment for Cd immobilization and fertility improvement in alkaline soils.

Rubik's cube PBA frameworks for optimizing the electrochemical performance in alkali metal-ion batteries.

PBA frameworks have stood out among metal-organic frameworks because of their easy preparation, excellent stability, porous structures, and rich redox properties. Unfortunately, their non-ideal conductivity and significant volume expansion during cycling prevent more widespread application in alkali-metal-ion (Li+, Na+, and K+) batteries. By changing the type and molar ratio of metal ions, Rubik's PBA frameworks with infinite structural variations were obtained in this study, just like the Rubik's cube undergoes infinite changes during the rotation. X-ray adsorption fine structure measurements have documented the existence and determined the coordination environment of the metal ions in the Rubik's PBA framework. Benefiting from the more stable Rubik's cube structures with diverse composition, enhanced conductivity, and greater adsorption capacity, the obtained Rubik's cubes CoM-PBA anodes, especially CoZn-PBA deliver the enhanced cycling and rate performance in all the alkali-metal-ion batteries. The findings are supported by density functional theory calculations. Ex-situ X-ray photoelectron spectroscopy, and in-situ X-ray diffraction measurements were undertaken to explore the storage mechanism of CoZn-PBA anodes. Our results further demonstrate that the Rubik's cube PBA framework-based materials could be widely applied in the field of alkali-metal-ion batteries.

Thiosalicylic-Acid-Mediated Coordination Structure of Nickel Center via Thermodynamic Modulation for Aqueous Ni-Zn Batteries.

Uniquely functional nanocomplexes with rich coordination environments are critical in energy storage. However, the construction of structurally versatile nanocomplexes remains challenging. In this study, a nickel-based complex with structural variations is designed via thermodynamic modulation using a dual-ligand synthesis strategy. A nickel-based nanomaterial (NiSA-SSA-160) with a large specific surface area is synthesized around the competing coordination of the host and guest molecules that differ in terms of the chemical properties of the O and S elements. Concurrently, the coordination environment of NiSA-SSA-160 is investigated via X-ray absorption fine structure spectroscopy. The thiol functional groups synergistically induced an electron-rich Ni structure, thus increasing the electron density of the central atom. The electrochemical performance of an assembled NiSA-SSA-160//Zn@CC battery is shown to improve significantly, with a maximum energy density of 0.54 mWh cm-2 and a peak power density of 49.49 mW cm-2. This study provides a new perspective regarding coordination transformations and offers an idea for the design of functionally rich nanomaterials.

Stabilizing Ni2+ in Hollow Nano MOF/Polymetallic Phosphides Composites for Enhanced Electrochemical Performance in 3D-Printed Micro-Supercapacitors.

Polymetallic phosphides exhibit favorable conductivities. A reasonable design of nano-metal-organic frame (MOF) composite morphologies and in situ introduction of polymetallic phosphides into the framework can effectively improve electrolyte penetration and rapid electron transfer. To address existing challenges, Ni, with a strong coordination ability with N, is introduced to partially replace Co in nano-Co-MOF composite. The hollow nanostructure is stabilized through CoNi bimetallic coordination and low-temperature controllable polymetallic phosphide generation rate. The Ni, Co, and P atoms, generated during reduction, effectively enhance electron transfer rate within the framework. X-ray absorption fine structure (XAFS) characterization results further confirm the existence of Ni-N, Ni-Ni, and Co-Co structures in the nanocomposite. The changes in each component during the charge-discharge process of the electrochemical reactions are investigated using in situ X-ray diffraction (XRD). Theoretical calculations further confirm that P can effectively improve conductivity. VZNPGC//MXene MSCs, constructed with active materials derived from the hollow nano MOF composites synthesized through the Ni2+ stabilization strategy, demonstrate a specific capacitance of 1184 mF cm-2, along with an energy density of 236.75 µWh cm-2 (power density of 0.14 mW cm-2). This approach introduces a new direction for the synthesis of highly conductive nano-MOF composites.

Interfacial Electronic Modulation of Dual-Monodispersed Pt-Ni3S2 as Efficacious Bi-Functional Electrocatalysts for Concurrent H2 Evolution and Methanol Selective Oxidation.

Constructing the efficacious and applicable bi-functional electrocatalysts and establishing out the mechanisms of organic electro-oxidation by replacing anodic oxygen evolution reaction (OER) are critical to the development of electrochemically-driven technologies for efficient hydrogen production and avoid CO2 emission. Herein, the hetero-nanocrystals between monodispersed Pt (~ 2 nm) and Ni3S2 (~ 9.6 nm) are constructed as active electrocatalysts through interfacial electronic modulation, which exhibit superior bi-functional activities for methanol selective oxidation and H2 generation. The experimental and theoretical studies reveal that the asymmetrical charge distribution at Pt-Ni3S2 could be modulated by the electronic interaction at the interface of dual-monodispersed heterojunctions, which thus promote the adsorption/desorption of the chemical intermediates at the interface. As a result, the selective conversion from CH3OH to formate is accomplished at very low potentials (1.45 V) to attain 100 mA cm-2 with high electronic utilization rate (~ 98%) and without CO2 emission. Meanwhile, the Pt-Ni3S2 can simultaneously exhibit a broad potential window with outstanding stability and large current densities for hydrogen evolution reaction (HER) at the cathode. Further, the excellent bi-functional performance is also indicated in the coupled methanol oxidation reaction (MOR)//HER reactor by only requiring a cell voltage of 1.60 V to achieve a current density of 50 mA cm-2 with good reusability.

Crystallization Engineering of CuNi2 S4 Ultra-Fine Nanocrystals with Optimized Band Structures for Efficient Photocatalytic Pollutant Degradation and Hydrogen Production.

The mono-dispersed cubic siegenite CuNi2 S4 ultra-fine (≈5 nm) nanocrystals are fabricated through crystallization engineering under hot injection. The strong hydroxylation on mostly exposed CuNi2 S4 (220) surface leads to the formation of multi-valence (Cu+ , Cu2+ , Ni2+ , Ni3+ ) species with unsaturated hybridization and coordination micro-environments, which can induce rich redox reactions to optimize interfacial kinetics for the adsorbed reaction intermediates. The as-synthesized CuNi2 S4 nanocrystals with ultra-small particle size and the characteristics of being highly dispersed can increase specific surface area and hydroxylated active sites, which considerably contribute to the improvement of photocatalytic activities. Experimental and theoretical studies indicate that the CuNi2 S4 with unique surface condition can properly modulate the charge density distribution and the electronic band structure, thus achieving an optimal band gap for enhancing visible light absorption. Additionally, the strong hydroxylation on CuNi2 S4 (220) surface can not only make the photocatalytic process stable in alkaline environment but also bring about an impurity level between conduction and valence band, which facilitates the separation of photo-induced charge carriers by suppressing the rapid re-combination of exited electrons and holes. The optimization of band structure should be the intrinsic reason for the efficient photocatalytic pollutant degradation and hydrogen production under visible light illumination.

A family of oxychloride amorphous solid electrolytes for long-cycling all-solid-state lithium batteries.

Solid electrolyte is vital to ensure all-solid-state batteries with improved safety, long cyclability, and feasibility at different temperatures. Herein, we report a new family of amorphous solid electrolytes, xLi2O-MCly (M = Ta or Hf, 0.8 ≤ x ≤ 2, y = 5 or 4). xLi2O-MCly amorphous solid electrolytes can achieve desirable ionic conductivities up to 6.6 × 10-3 S cm-1 at 25 °C, which is one of the highest values among all the reported amorphous solid electrolytes and comparable to those of the popular crystalline ones. The mixed-anion structural models of xLi2O-MCly amorphous SEs are well established and correlated to the ionic conductivities. It is found that the oxygen-jointed anion networks with abundant terminal chlorines in xLi2O-MCly amorphous solid electrolytes play an important role for the fast Li-ion conduction. More importantly, all-solid-state batteries using the amorphous solid electrolytes show excellent electrochemical performance at both 25 °C and -10 °C. Long cycle life (more than 2400 times of charging and discharging) can be achieved for all-solid-state batteries using the xLi2O-TaCl5 amorphous solid electrolyte at 400 mA g-1, demonstrating vast application prospects of the oxychloride amorphous solid electrolytes.

Confined Synthesis of Amorphous Al2 O3 Framework Nanocomposites Based on the Oxygen-Potential Diagram as Sulfur Hosts for Catalytic Conversion.

Sulfur cathodes in Li-S batteries suffer significant volumetric expansion and lack of catalytic activity for polysulfide conversion. In this study, a confined self-reduction synthetic route is developed for preparing nanocomposites using diverse metal ions (Mn2+ , Co2+ , Ni2+ , and Zn2+ )-introduced Al-MIL-96 as precursors. The Ni2+ -introduced Al-MIL-96-derived nanocomposite contains a "hardness unit", amorphous aluminum oxide framework, to restrain the volumetric expansion, and a "softness unit", Ni nanocrystals, to improve the catalytic activity. The oxygen-potential diagram theoretically explains why Ni2+ is preferentially reduced. Postmortem microstructure characterization confirms the suppressive volume expansion. The in situ ultraviolet-visible measurements are performed to probe the catalytic activity of polysulfide conversion. This study provides a new perspective for designing nanocomposites with "hardness units" and "softness units" as sulfur or other catalyst hosts.