Synthesizing nickel single atom catalyst via SiO2 protection strategy for efficient CO2 electroreduction to CO in a wide potential range.

At present, electrochemical CO2 reduction has been developed towards industrial current density, but the high faradaic efficiency at wide potential range or large current density is still an arduous task. Therefore, in this work, the highly exposed Ni single atoms (NiNCR-0.72) was synthesized through simple metal organic frameworks (MOFs)-derived method with SiO2 protection strategy. The obtained catalyst keeps CO faradaic efficiency (FECO) above 91 % under the wide potential range, and achieves a high FECO of 96.0 % and large CO partial current density of -206.8 mA cm-2 at -0.7 V in flow cell. The experimental results and theoretical calculation disclose that NiNCR-0.72 possesses the robust structure with rich mesopore and more highly exposed Ni-N active sites under SiO2 protection, which could facilitate CO2 transportation, lower energy barrier of CO2 reduction, and raise difficulty of hydrogen evolution reaction. The protection strategy is instructive to the synthesis of other MOFs-derived metal single atoms.

Rapidly Prepared Lithophilic Frameworks Stabilizes Lithium Anodes via Altered Lithium Deposition Patterns.

Lithium metal batteries are regarded as promising candidates for next-generation energy storage systems. However, their anodes are susceptible to interfacial instability due to significant volume changes, which significantly impacts the cycle life of lithium metal batteries. Here, a rapid method for the fabrication of 3D-hosts with interface modified layers is reported. A simple infiltration and heating process enables the transformation of copper foam into Zn-BDC-modified copper foam within 1 min, rendering it suitable for use as a current collector for lithium metal anodes. The Zn-BDC nanosheets with high lithiophilicity are uniformly distributed on the surface of the current collector, facilitating the uniform deposition of lithium and reducing the volume change. Consequently, the half cell exhibits a remarkably low overpotential (26 mV) at a current-density of 4 mA cm-2 and is cycled stably for 1000 h. Furthermore, it demonstrates a significant enhancement in performance in the LiFePO4 full cell. This study provides a crucial reference on the connection between the interfacial modification of the current collector and the lithium deposition behavior, which promotes the practicalization of lithium metal anodes.

Antigravity Autonomous Superwettable Pumps for Spontaneous Separation of Oil-Water Emulsions.

Oil-water separation based on superwettable materials offers a promising way for the treatment of oil-water mixtures and emulsions. Nevertheless, such separation techniques often require complex devices and external energy input. Therefore, it remains a great challenge to separate oil-water mixtures and emulsions through an energy-efficient, economical, and sustainable way. Here, a novel approach demonstrating the successful separation of oil-water emulsions using antigravity-driven autonomous superwettable pumps is presented. By transitioning from traditional gravity-driven to antigravity-driven separation, the study showcases the unprecedented success in purifying oil/water from emulsions by capillary/siphon-driven superwettable autonomous pumps. These pumps, composed of self-organized interconnected channels formed by the packing of superhydrophobic and superhydrophilic sand particles, exhibit outstanding separation flux, efficiency, and recyclability. The findings of this study not only open up a new avenue for oil-water emulsion separation but also hold promise for profound impacts in the field.

Layered Cathode with Ultralow Strain Empowers Rapid-Charging and Slow-Discharging Capability in Sodium Ion Battery.

The development of the electric vehicle industry has spurred demand for secondary batteries capable of rapid-charging and slow-discharging. Among them, sodium-ion batteries (SIBs) with layered oxide as the cathode exhibit competitive advantages due to their comprehensive electrochemical performance. However, to meet the requirements of rapid-charging and slow-discharging scenarios, it is necessary to further enhance the rate performance of the cathode material to achieve symmetrical capacity at different rates. Simultaneously, minimizing lattice strain during asymmetric electrochemical processes is also significant in alleviating strain accumulation. In this study, the ordered distribution of transition metal layers and the diffusion pathway of sodium ions are optimized through targeted K-doping of sodium layers, leading to a reduction of the diffusion barrier and endowment of prominent rate performance. At a 20C rate, the capacity of the cathode can reach 94% of that at a 0.1C rate. Additionally, the rivet effect of the sodium layers resulted in a global volume strain of only 0.03% for the modified cathode during charging at a 10C rate and discharging at a 1C rate. In summary, high-performance SIBs, with promising prospects for rapid-charging and slow-discharging capability, are obtained through the regulation of sodium layers, opening up new avenues for commercial applications.

Effects of Brown Fishmeal on Growth Performance, Digestibility, and Lipid Metabolism of the Chinese Soft-Shelled Turtle (Pelodiscus sinensis).

The aim of this study was to evaluate the effect of brown fishmeal in replacement of white fishmeal in the diet of Chinese soft-shelled turtles and to find the optimal amount of brown fishmeal to add. Five experimental groups were set up and fed to animals, and they were composed by different proportions of white and brown fishmeal: G1 (30% white and 25% brown fishmeal), G2 (25% white and 30% brown fishmeal), G3 (20% white and 35% brown fishmeal), G4 (15% white and 40% brown fishmeal), G5 (10% white and 45% brown fishmeal). G1 is regarded as the control group. Turtles were randomly divided into five experimental groups with four replicates each. The experiment lasted 72 days. The results showed that the WGR, SGR, FCR, and HSI of the G3 group were not significantly different from those of the control group (P > 0.05). In addition, brown fishmeal can increase the crude protein content in the muscles of them. Among the serum biochemical indices, there was no significant difference between the G3 group and the G1 group, except for the level of TG (P > 0.05). Meanwhile, the activities of AST, ALT, and CAT in the liver of the G3 group did not differ significantly from those of the G1 group (P > 0.05). However, the activities of ACP, AKP, and T-AOC were significantly decreased in the G3 group (P < 0.05). In addition, the alteration of fishmeal did not affect the digestive enzyme activities in the stomach, liver, and intestine, and there is no significant difference (P > 0.05). Importantly, with increasing brown fishmeal addition, the expression of Fas, Pparγ, Scd, and Stat3 showed a significant increase, while the expression of Bmp4 decreased significantly (P < 0.05). In this study, the addition of 20% white fishmeal and 35% brown fishmeal to the diet of Chinese soft-shelled turtles did not adversely affect growth performance. Therefore, 20% white fishmeal and 35% brown fishmeal are the most practical feed formulations for Chinese soft-shelled turtles in this study.

Ionic Liquids Modulating Local Microenvironment of Ni-Fe Binary Single Atom Catalyst for Efficient Electrochemical CO2 Reduction.

The Ni and Fe dual-atom catalysts still undergo strikingly attenuation under high current density and high overpotential. To ameliorate the issue, the ionic liquids with different cations or anions are used in this work to regulate the micro-surface of nitrogen-doped carbon supported Ni and Fe dual-atom sites catalyst (NiFe-N-C) by an impregnation method. The experimental data reveals the dual function of ionic liquids, which enhances CO2 adsorption ability and modulates electronic structure, facilitating CO2 anion radical (CO2 •¯) stabilization and decreasing onset potential. The theoretical calculation results prove that the attachment of ionic liquids modulates electronic structure, reduces energy barrier of CO2 •¯ formation, and enhances overall ECR performance. Based on these merits, BMImPF6 modified NiFe-N-C (NiFe-N-C/BMImPF6) achieves the high CO faradaic efficiency of 91.9% with a CO partial current density of -120 mA cm-2 at -1.0 V. When the NiFe-N-C/BMImPF6 is assembled as cathode of Zn-CO2 battery, it delivers the highest power density of 2.61 mW cm-2 at 2.57 mA cm-2 and superior cycling stability. This work will afford a direction to modify the microenvironment of other dual-atom catalysts for high-performance CO2 electroreduction.

Probing spin waves in Co3O4 nanoparticles for magnonics applications.

The magnetic properties of spinel nanoparticles can be controlled by synthesizing particles of a specific shape and size. The synthesized nanorods, nanodots and cubic nanoparticles have different crystal planes selectively exposed on the surface. The surface effects on the static magnetic properties are well documented, while their influence on spin waves dispersion is still being debated. Our ability to manipulate spin waves using surface and defect engineering in magnetic nanoparticles is the key to designing magnonic devices. We synthesized cubic and spherical nanoparticles of a classical antiferromagnetic material Co3O4 to study the shape and size effects on their static and dynamic magnetic proprieties. Using a combination of experimental methods, we probed the magnetic and crystal structures of our samples and directly measured spin wave dispersions using inelastic neutron scattering. We found a weak, but unquestionable, increase in exchange interactions for the cubic nanoparticles as compared to spherical nanoparticle and bulk powder reference samples. Interestingly, the exchange interactions in spherical nanoparticles have bulk-like properties, despite a ferromagnetic contribution from canted surface spins.

Ampere-hour-scale soft-package potassium-ion hybrid capacitors enabling 6-minute fast-charging.

Extreme fast charging of Ampere-hour (Ah)-scale electrochemical energy storage devices targeting charging times of less than 10 minutes are desired to increase widespread adoption. However, this metric is difficult to achieve in conventional Li-ion batteries due to their inherent reaction mechanism and safety hazards at high current densities. In this work, we report 1 Ah soft-package potassium-ion hybrid supercapacitors (PIHCs), which combine the merits of high-energy density of battery-type negative electrodes and high-power density of capacitor-type positive electrodes. The PIHC consists of a defect-rich, high specific surface area N-doped carbon nanotube-based positive electrode, MnO quantum dots inlaid spacing-expanded carbon nanotube-based negative electrode, carbonate-based non-aqueous electrolyte, and a binder- and current collector-free cell design. Through the optimization of the cell configuration, electrodes, and electrolyte, the full cells (1 Ah) exhibit a cell voltage up to 4.8 V, high full-cell level specific energy of 140 Wh kg-1 (based on the whole mass of device) with a full charge of 6 minutes. An 88% capacity retention after 200 cycles at 10 C (10 A) and a voltage retention of 99% at 25 ± 1 °C are also demonstrated.

Spontaneous Internal Electric Field in Heterojunction Boosts Bifunctional Oxygen Electrocatalysts for Zinc-Air Batteries: Theory, Experiment, and Application.

Heterojunctions are a promising class of materials for high-efficiency bifunctional oxygen electrocatalysts in both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). However, the conventional theories fail to explain why many catalysts behave differently in ORR and OER, despite a reversible path (* O2 ⇋* OOH⇋* O⇋* OH). This study proposes the electron-/hole-rich catalytic center theory (e/h-CCT) to supplement the existing theories, it suggests that the Fermi level of catalysts determines the direction of electron transfer, which affects the direction of the oxidation/reduction reaction, and the density of states (DOS) near the Fermi level determines the accessibility for injecting electrons and holes. Additionally, heterojunctions with different Fermi levels form electron-/hole-rich catalytic centers near the Fermi levels to promote ORR/OER, respectively. To verify the universality of the e/h-CCT theory, this study reveals the randomly synthesized heterostructural Fe3 N-FeN0.0324 (Fex N@PC with DFT calculations and electrochemical tests. The results show that the heterostructural F3 N-FeN0.0324 facilitates the catalytic activities for ORR and OER simultaneously by forming an internal electron-/hole-rich interface. The rechargeable ZABs with Fex N@PC cathode display a high open circuit potential of 1.504 V, high power density of 223.67 mW cm-2 , high specific capacity of 766.20 mAh g-1 at 5 mA cm-2 , and excellent stability for over 300 h.

Role of Substitution Elements in Enhancing the Structural Stability of Li-Rich Layered Cathodes.

Element doping/substitution has been recognized as an effective strategy to enhance the structural stability of layered cathodes. However, abundant substitution studies not only lack a clear identification of the substitution sites in the material lattice, but the rigid interpretation of the transition metal (TM)-O covalent theory is also not sufficiently convincing, resulting in the doping/substitution proposals being dragged into design blindness. In this work, taking Li1.2Ni0.2Mn0.6O2 as a prototype, the intense correlation between the "disordered degree" (Li/Ni mixing) and interface-structure stability (e.g., TM-O environment, slab/lattice, and Li+ reversibility) is revealed. Specifically, the degree of disorder induced by the Mg/Ti substitution extends in the opposite direction, conducive to sharp differences in the stability of TM-O, Li+ diffusion, and anion redox reversibility, delivering fairly distinct electrochemical performance. Based on the established paradigm of systematic characterization/analysis, the "degree of disorder" has been shown to be a powerful indicator of material modification by element substitution/doping.

A LaCl3-based lithium superionic conductor compatible with lithium metal.

Inorganic superionic conductors possess high ionic conductivity and excellent thermal stability but their poor interfacial compatibility with lithium metal electrodes precludes application in all-solid-state lithium metal batteries1,2. Here we report a LaCl3-based lithium superionic conductor possessing excellent interfacial compatibility with lithium metal electrodes. In contrast to a Li3MCl6 (M = Y, In, Sc and Ho) electrolyte lattice3-6, the UCl3-type LaCl3 lattice has large, one-dimensional channels for rapid Li+ conduction, interconnected by La vacancies via Ta doping and resulting in a three-dimensional Li+ migration network. The optimized Li0.388Ta0.238La0.475Cl3 electrolyte exhibits Li+ conductivity of 3.02 mS cm-1 at 30 °C and a low activation energy of 0.197 eV. It also generates a gradient interfacial passivation layer to stabilize the Li metal electrode for long-term cycling of a Li-Li symmetric cell (1 mAh cm-2) for more than 5,000 h. When directly coupled with an uncoated LiNi0.5Co0.2Mn0.3O2 cathode and bare Li metal anode, the Li0.388Ta0.238La0.475Cl3 electrolyte enables a solid battery to run for more than 100 cycles with a cutoff voltage of 4.35 V and areal capacity of more than 1 mAh cm-2. We also demonstrate rapid Li+ conduction in lanthanide metal chlorides (LnCl3; Ln = La, Ce, Nd, Sm and Gd), suggesting that the LnCl3 solid electrolyte system could provide further developments in conductivity and utility.

Synergistic activation of anionic redox via cosubstitution to construct high-capacity layered oxide cathode materials for sodium-ion batteries.

As a potential substitute for lithium-ion battery, sodium-ion batteries (SIBs) have attracted a tremendous amount of attention due to their advantages in terms of cost, safety and sustainability. Nevertheless, further improvement of the energy density of cathode materials in SIBs remains challenging and requires the activation of anion redox reaction (ARR) activity to provide additional capacity. Herein, we report a high-performance Mn-based sodium oxide cathode material, Na0.67Mg0.1Zn0.1Mn0.8O2 (NMZMO), with synergistic activation of ARR by cosubstitution. This material can deliver an ultra-high capacity of âˆ¼233 mAh/g at 0.1 C, which is significantly higher than their single-cation-substituted counterparts and among the best in as-reported MgMn or ZnMn-based cathodes. Various spectroscopic techniques were comprehensively employed and it was demonstrated that the higher capacity of NMZMO originated from the enhanced ARR activity. Neutron pair distribution function and resonant inelastic X-ray scattering experiments revealed that out-of-plane migration of Mg/Zn occurred upon charging and oxygen anions in the form of molecular O2 were trapped in vacancy clusters in the fully-charged-state. In NMZMO, Mg and Zn mutually interacted with each other to migrate toward tetrahedral sites, which provided a prerequisite for further ARR activity enhancement to form more trapped molecular O2. These findings provide unique insight into the ARR mechanism and can guide the development of high-performance cathode materials through ARR enhancement strategies.

Nanoparticle-induced morphological transformation in block copolymer-based nanocomposites.

By controlling the chemical composition and the spatial organization of nanoparticles, hybrid nanocomposites incorporating ordered arrangements of nanoparticles could be endowed with exotic physical and chemical properties to fulfill demands in advanced electronics or energy-harvesting devices. However, a simple method to fabricate hybrid nanocomposites with precise control of nanoparticle distribution is still challenging. We demonstrate that block copolymer-based nanocomposites containing well-ordered nanoparticles with various morphologies can be readily obtained by adjusting the nanoparticle concentration. Moreover, the structural evolution of nanocomposite thin films as a function of nanoparticle loading is unveiled using grazing-incidence transmission small-angle X-ray scattering and atomic force microscopy. The morphological transformation proceeds through a phase transition from perforated lamellae to in-plane cylinder layout, followed by structural changes. The successful achievement of a variety of morphologies represents an effective and straightforward approach to producing functional hybrid nanocomposites for potential applications in various functional devices.

High-Efficiency Air Filter Media with a Three-Dimensional Network Composed of Core-Shell Zeolitic Imidazolate Framework-8@Tunicate Nanocellulose for PM0.3 Removal.

Particulate matter (PM) in air has seriously endangered human health. Especially, PM0.3 can easily enter the lungs and blood through breathing. Herein, an air filter with a three-dimensional (3D) network consisting of core-shell structured fibers was designed by in situ growth of zeolitic imidazolate framework-8 on tunicate nanocellulose/glass fiber composite filter media (ZIF-8@TNC/GF). The filtration performance of the obtained ZIF-8@TNC/GF membranes against sodium chloride particles with the MPPS (most penetrating particle size) was investigated. The air filter media at the optimal ratio of ZIF-8 exhibited an ultrahigh efficiency of 99.998% and a quality factor of 0.0308 Pa-1 for PM0.3. Further characterizations showed that the ZIF-8@TNC/GF air filter had a hierarchical and rich pore structure, showing a large specific surface area (50.3 m2 g-1). More significantly, compared with the TNC/GF prepared by the dipping method, TNCs changed from the original two-dimensional (2D) nonuniform network to a uniform 3D network after the ZIF-8 was introduced. Moreover, the ZIF-8@TNC fibers with a core-shell structure inhibited the aggregation of nanocellulose. This study will shed light on the fabrication of high-efficiency TNC composite air filter media with fluffy 3D networks.

Highly Distorted Grain Boundary with an Enhanced Carrier/Phonon Segregation Effect Facilitates High-Performance Thermoelectric Materials.

Grain boundary plays an important role in determining the phonon/carrier transport behaviors of thermoelectric (TE) materials, especially for the polycrystalline materials with the average grain size in nanoscale dimensions. Adjusting the grain size and boundaries of TE materials is considered as an effective approach to decouple TE parameters and thereby synergistically optimize the TE performance. Here, the highly distorted grain boundary with an enhanced carrier/phonon segregation effect is introduced to the commercial n-type Bi2Te2.7Se0.3 matrix. The existence of highly distorted grain boundaries can not only enhance the interfacial Seebeck coefficient without significant detriment to the electrical conductivity but also increase the interfacial thermal resistance of grain boundaries, leading to the synergistic reduction of the thermal conductivity. As a result, a peak figure of merit zTmax ≈ 1.22@425 K and an average zTavg ≈ 1.1(300-500 K) are obtained, which are about 55 and 57% higher than the corresponding values of the commercial Bi2Te2.7Se0.3 matrix, respectively. This work represents a new avenue for improving the commercial Bi2Te2.7Se0.3 TE material, which could further promote the development of the TE technology.

Heterostructural Interface in Fe3C-TiN Quantum Dots Boosts Oxygen Reduction Reaction for Al-Air Batteries.

Oxygen reduction electrocatalysts play important roles in metal-air batteries. Herein, Fe3C-TiN heterostructural quantum dots loaded on carbon nanotubes (FCTN@CNTs) are prepared as electrocatalysts for the oxygen reduction reaction (ORR) through a one-pot pyrolysis. The Fe3C-TiN quantum dots with a diameter of 2-5 nm show the unique characteristic of heterostructural interface. The as-prepared FCTN@CNTs display Pt/C comparable ORR performance (Eonset 1.06 and E1/2 0.95 V) in alkaline medium, which is ascribed to the heterostructural interface between TiN and Fe3C. Furthermore, the Al-air batteries with the FCTN@CNT catalyst display superior discharge performance, demonstrating good feasibility for practical application. This work provides an effective new method to synthesize affordable and efficient oxygen reduction reaction catalysts.

Twin boundary defect engineering improves lithium-ion diffusion for fast-charging spinel cathode materials.

Defect engineering on electrode materials is considered an effective approach to improve the electrochemical performance of batteries since the presence of a variety of defects with different dimensions may promote ion diffusion and provide extra storage sites. However, manipulating defects and obtaining an in-depth understanding of their role in electrode materials remain challenging. Here, we deliberately introduce a considerable number of twin boundaries into spinel cathodes by adjusting the synthesis conditions. Through high-resolution scanning transmission electron microscopy and neutron diffraction, the detailed structures of the twin boundary defects are clarified, and the formation of twin boundary defects is attributed to agminated lithium atoms occupying the Mn sites around the twin boundary. In combination with electrochemical experiments and first-principles calculations, we demonstrate that the presence of twin boundaries in the spinel cathode enables fast lithium-ion diffusion, leading to excellent fast charging performance, namely, 75% and 58% capacity retention at 5 C and 10 C, respectively. These findings demonstrate a simple and effective approach for fabricating fast-charging cathodes through the use of defect engineering.

Freely Moldable Modified Starch as a Sustainable and Recyclable Plastic.

Efficiently preparing a starch-based plastic with moisture insensitivity and toughness is a challenge to improve the high-value utilization of polysaccharide resources. Herein, a sustainable, recyclable starch-based plastic was prepared in a facile and eco-friendly way. First, starch acetoacetate (SAA) with different degrees of substitution (DSs) was synthesized by transesterification. Then, the SAA film was obtained through a solvent-free hot-pressing method. Notably, SAA with different DSs exhibited various glass transition temperatures (109-140 °C), and SAA with high DS (>0.84) was insoluble even after boiling in water for 1 h. Also, the maximum fracture strength of SAA film up to 15.5 MPa and a maximum elongation at break up to 30% were reached . In addition, the starch-based plastic film retained the original mechanical properties after three cycles of hot processing. In consideration of the facile preparation process, this protocol provided a new avenue for developing sustainable and recyclable starch-based plastics.

Enhancing the Electrochemical Performance and Structural Stability of Ni-Rich Layered Cathode Materials via Dual-Site Doping.

Ni-rich layered cathode materials are considered as promising electrode materials for lithium ion batteries due to their high energy density and low cost. However, the low rate performance and poor electrochemical stability hinder the large-scale application of Ni-rich layered cathodes. In this work, both the rate performance and the structural stability of the Ni-rich layered cathode LiNi0.8Co0.1Mn0.1O2 are significantly improved via the dual-site doping of Nb on both lithium and transition-metal sites, as revealed by neutron diffraction results. The dual-site Nb-doped LiNi0.8Co0.1Mn0.1O2 delivers 202.8 mAh·g-1 with a capacity retention of 81% after 200 electrochemical cycles, which is much higher than that of pristine LiNi0.8Co0.1Mn0.1O2. Moreover, a discharge capacity of 176 mAh·g-1 at 10C rate illustrates its remarkable rate capability. Through in situ X-ray diffraction and electronic transport property measurements, it was demonstrated that the achievement of dual-site doping in the Ni-rich layered cathode can not only suppress the Li/Ni disordering and facilitate the lithium ion transport process but also stabilize the layered structure against local collapse and structural distortion. This work adopts a dual-site-doping approach to enhance the electrochemical performance and structural stability of Ni-rich cathode materials, which could be extended as a universal modification strategy to improve the electrochemical performance of other cathode materials.