A bio-based functional separator enables dendrite-free anodes in aqueous zinc-ion batteries.

Aqueous zinc-ion batteries (AZIBs) have garnered considerable interest as potential solutions for large-scale energy storage systems, owing to their cost-effectiveness and high safety. Nonetheless, the development of AZIBs is hindered by significant challenges associated with dendrite growth and side reactions on Zn anodes. Here, a bio-based separator derived from cellulose was developed for the dendrite-free anode in AZIBs. In addition, the separator is notable for its ultra-low cost and biodegradability in contrast to the commonly used commercial glass fiber (GF) separators. The mechanical strength of the separator is enhanced by the cross-linking of hydrogen bonds, effectively inhibiting dendrite growth. The zinc-philic groups facilitate better binding to Zn2+, resulting in uniform nucleation and deposition. The hydrophilic groups aid in trapping water molecules, thereby preventing side reactions of the electrolyte. The Zn||Zn symmetric cell with this separator can sustain a long cycle life for over 800 h, indicating stable Zn2 + plating and stripping with suppressed dendrite growth. Concurrently, the assembled Zn||VO2 full batteries exhibited a capacity retention rate of 61.87% after 1,000 cycles at 1 A g-1 with an initial capacity of 140 mAh g-1. This work highlights a stable, economical, and eco-friendly approach to the design of bio-based separators in AZIBs for sustainable energy storage systems.

A single-bridge interleaved three-level LLC resonant converter with current sharing capability for fuel cell system.

This paper propose a wide gain single-bridge interleaved three-level LLC resonant converter with current sharing capability. This novel converter offers numerous advantages, including low cost, low current ripple, reduced voltage and current stress, widely gain range, high efficiency, good current sharing capability and versatile application scalability. Utilizing the three-level inverter + full-wave rectifier LLC converter as a representative case, the paper conducts an in-depth analysis and research on the proposed method. Finality, a 600 W experimental prototype was constructed and tested. Experimental results reveal that the proposed converter exhibits lower current ripple and a broader gain range. Moreover, the converter shows good current sharing capability (with a resonant element tolerance of 10%, the current error between the two phases does not exceed 12%) and high efficiency (peaking at 95.8%).

Superoxide Dismutase Catalyzed Size-Adjustable Selenium Nanoparticles in Saccharomyces boulardii.

Selenium nanoparticles (SeNPs) are important and safe food and feed additives that can be used for dietary supplementation. In this study, a mutagenic strain of Saccharomyces boulardii was employed to obtain biologically synthesized SeNPs (BioSeNPs) with the desired particle size by controlling the dosage and duration of sodium selenite addition, and the average particle size achieved was 55.8 nm with protease A encapsulation. Transcriptomic analysis revealed that increased expression of superoxide dismutase 1 (SOD1) in the mutant strain effectively promoted the synthesis of BioSeNPs and the formation of smaller nanoparticles. Under sodium selenite stress, the mutant strain exhibited significantly increased expression of glutathione peroxidase 2 (GPx2), which was significantly greater in the mutant strain than in the wild type, facilitating the synthesis of glutathione selenol and providing abundant substrates for the production of BioSeNPs. Furthermore, based on the experimental results and transcriptomic analysis of relevant genes such as sod1, gpx2, the thioredoxin reductase 1 gene (trr1) and the thioredoxin reductase 2 gene (trr2), a yeast model for the size-controlled synthesis of BioSeNPs was constructed. This study provides an important theoretical and practical foundation for the green synthesis of controllable-sized BioSeNPs or other metal nanoparticles with potential applications in the fields of food, feed, and biomedicine.

Artificial Intelligence Aided Lipase Production and Engineering for Enzymatic Performance Improvement.

With the development of artificial intelligence (AI), tailoring methods for enzyme engineering have been widely expanded. Additional protocols based on optimized network models have been used to predict and optimize lipase production as well as properties, namely, catalytic activity, stability, and substrate specificity. Here, different network models and algorithms for the prediction and reforming of lipase, focusing on its modification methods and cases based on AI, are reviewed in terms of both their advantages and disadvantages. Different neural networks coupled with various algorithms are usually applied to predict the maximum yield of lipase by optimizing the external cultivations for lipase production, while one part is used to predict the molecule variations affecting the properties of lipase. However, few studies have directly utilized AI to engineer lipase by affecting the structure of the enzyme, and a set of research gaps needs to be explored. Additionally, future perspectives of AI application in enzymes, including lipase engineering, are deduced to help the redesign of enzymes and the reform of new functional biocatalysts. This review provides a new horizon for developing effective and innovative AI tools for lipase production and engineering and facilitating lipase applications in the food industry and biomass conversion.

Recent Advances in Structural Optimization and Surface Modification on Current Collectors for High-Performance Zinc Anode: Principles, Strategies, and Challenges.

The last several years have witnessed the prosperous development of zinc-ion batteries (ZIBs), which are considered as a promising competitor of energy storage systems thanks to their low cost and high safety. However, the reversibility and availability of this system are blighted by problems such as uncontrollable dendritic growth, hydrogen evolution, and corrosion passivation on anode side. A functionally and structurally well-designed anode current collectors (CCs) is believed as a viable solution for those problems, with a lack of summarization according to its working mechanisms. Herein, this review focuses on the challenges of zinc anode and the mechanisms of modified anode CCs, which can be divided into zincophilic modification, structural design, and steering the preferred crystal facet orientation. The possible prospects and directions on zinc anode research and design are proposed at the end to hopefully promote the practical application of ZIBs.

Effect of Alloying Powders on Microstructure and Mechanical Properties of Aluminum Alloy Arc Additive Manufacturing.

Cold metal transfer arc additive manufacturing technique was used to produce 5356 aluminum alloy by adding refining agents to solve the problems of coarse grains and poor performance. Metallic powders (Ti, TiH, and Ti+B4C) were used to refine the grain size and promote the mechanical properties of the alloy. The effects of refining agents on the microstructure and mechanical properties of straight wall samples (SWSs) were studied. Samples with Ti+B4C addition had a profound impact on morphology. However, the TiH added sample revealed uneven transition between sediment layers, unstable precipitation process, unstable wall height and wall width, poor morphology, and defects. All SWSs with powder addition revealed the formation of the Al3Ti phase. Moreover, the columnar grains between the layers were transformed into equiaxed grains and finer grains at the center of the layers. There was a significant effect of TiH on the grain refinement. The samples with Ti demonstrated superior mechanical properties. The tensile strength and elongation of the SWSs increased by 28 MPa and 4.6% in the parallel additive direction and by 37 MPa and 8.9% in the vertical direction. The addition of Ti also contributed to the even distribution of the mechanical properties in both directions.

Molecular-Crowding Effect Mimicking Cold-Resistant Plants to Stabilize the Zinc Anode with Wider Service Temperature Range.

Growth of dendrites, the low plating/stripping efficiency of Zn anodes, and the high freezing point of aqueous electrolytes hinder the practical application of aqueous Zn-ion batteries. Here, a zwitterionic osmolyte-based molecular crowding electrolyte is presented, by adding betaine (Bet, a by-product from beet plant) to the aqueous electrolyte, to solve the abovementioned problems. Substantive verification tests, density functional theory calculations, and ab initio molecular dynamics simulations consistently reveal that side reactions and growth of Zn dendrites are restrained because Bet can break Zn2+ solvation and regulate oriented 2D Zn2+ deposition. The Bet/ZnSO4 electrolyte enables superior reversibility in a Zn-Cu half-cell to achieve a high Coulombic efficiency >99.9% for 900 cycles (≈1800 h), and dendrite-free Zn plating/stripping in Zn-Zn cells for 4235 h at 0.5 mA cm-2 and 0.5 mAh cm-2 . Furthermore, a high concentration of Bet lowers the freezing point of the electrolyte to -92 °C via the molecular-crowding effect, which ensures the stable operation of the aqueous batteries at -30 °C. This innovative concept of such a molecular crowding electrolyte will inject new vitality into the development of multifunctional aqueous electrolytes.

3D Sodiophilic Ti3C2 MXene@g-C3N4 Hetero-Interphase Raises the Stability of Sodium Metal Anodes.

Owing to several advantages of metallic sodium (Na), such as a relatively high theoretical capacity, low redox potential, wide availability, and low cost, Na metal batteries are being extensively studied, which are expected to play a major role in the fields of electric vehicles and grid-scale energy storage. Although considerable efforts have been devoted to utilizing MXene-based materials for suppressing Na dendrites, achieving a stable cycling of Na metal anodes remains extremely challenging due to, for example, the low Coulombic efficiency (CE) caused by the severe side reactions. Herein, a g-C3N4 layer was attached in situ on the Ti3C2 MXene surface, inducing a surface state reconstruction and thus forming a stable hetero-interphase with excellent sodiophilicity between the MXene and g-C3N4 to inhibit side reactions and guide uniform Na ion flux. The 3D construction can not only lower the local current density to facilitate uniform Na plating/stripping but also mitigate volume change to stabilize the electrolyte/electrode interphase. Thus, the 3D Ti3C2 MXene@g-C3N4 nanocomposite enables much enhanced average CEs (99.9% at 1 mA h cm-2, 0.5 mA cm-2) in asymmetric half cells, long-term stability (up to 700 h) for symmetric cells, and stable cycling (up to 800 cycles at 2 C), together with outstanding rate capability (up to 20 C), of full cells. The present study demonstrates an approach in developing practically high performance for Na metal anodes.

Prelithiation: A Crucial Strategy for Boosting the Practical Application of Next-Generation Lithium Ion Battery.

With the urgent market demand for high-energy-density batteries, the alloy-type or conversion-type anodes with high specific capacity have gained increasing attention to replace current low-specific-capacity graphite-based anodes. However, alloy-type and conversion-type anodes have large initial irreversible capacity compared with graphite-based anodes, which consume most of the Li+ in the corresponding cathode and severely reduces the energy density of full cells. Therefore, for the practical application of these high-capacity anodes, it is urgent to develop a commercially available prelithiation technique to compensate for their large initial irreversible capacity. At present, various prelithiation methods for compensating the initial irreversible capacity of the anode have been reported, but due to their respective shortcomings, large-scale commercial applications have not yet been achieved. In this review, we have systematically summarized and analyzed the advantages and challenges of various prelithiation methods, providing enlightenment for the further development of each prelithiation strategy toward commercialization and thus facilitating the practical application of high-specific-capacity anodes in the next-generation high-energy-density lithium-ion batteries.

Anodic Oxidation Strategy toward Structure-Optimized V2O3 Cathode via Electrolyte Regulation for Zn-Ion Storage.

The lack of suitable cathodes is one of the key reasons that impede the development of aqueous zinc-ion batteries. Because of the inherently unsuitable structure and inferior physicochemical properties, the low-valent V2O3 as Zn2+ host could not be effectively discharged. Herein, we demonstrate that V2O3 (theoretical capacity up to 715 mAh g-1) can be utilized as a high-performance cathode material by an in situ anodic oxidation strategy. Through simultaneously regulating the concentration of the electrolyte and the morphology of the V2O3 sample, the ultraefficient anodic oxidation process of the V2O3 cathode was achieved within the first charging, and the mechanism was also schematically investigated. As expected, the V2O3 cathode with a hierarchical microcuboid structure achieved a nearly two-electron transfer process, enabling a high discharging capacity of 625 mAh g-1 at 0.1 A g-1 (corresponding to a high energy density of 406 Wh kg-1) and cycling stability (100% capacity retention after 10 000 cycles). This work not only sheds light on the phase transition process of low-valent V2O3 but also exploits a method toward design of advanced cathode materials.

Interfacial and Electronic Modulation via Localized Sulfurization for Boosting Lithium Storage Kinetics.

Structural modulation endows electrochemical hybrids with promising energy storage properties owing to their adjustable interfacial and/or electronic characteristics. For MXene-based materials, however, the facile but effective strategies for tuning their structural properties at nanoscale are still lacking. Herein, 3D crumpled S-functionalized Ti3 C2 Tx substrate is rationally integrated with Fe3 O4 /FeS heterostructures via coprecipitation and subsequent partial sulfurization to induce a highly active and stable electrode architecture. The unique heterostructures with tuned electronic properties can induce improved kinetics and structural stability. The surface engineering by S terminations on the MXene further unlocks extra (pseudo)capacitive lithium storage. Serving as anode for lithium storage, the optimized electrode delivers an excellent long-term cycling stability (913.9 mAh g-1 after 1000 cycles at 1 A g-1 ) and superior rate capability (490.4 mAh g-1 at 10 A g-1 ). Moreover, the (de)lithiation pathways associated with energy storage mechanisms are further revealed by operando X-ray diffraction, in situ electroanalytical techniques, and first-principles calculations. The hybrid electrode is proved to undergo stepwise phase transformations during discharging but a relatively uniform reconversion during charging, suggesting an asymmetric conversion mechanism. This work provides a novel strategy for designing high-performance hybrids and paves the way for in-depth understanding of complex lithium intercalation and conversion reactions.

A MIL-47(V) derived hierarchical lasagna-structured V2O3@C hollow microcuboid as an efficient sulfur host for high-performance lithium-sulfur batteries.

Lithium-sulfur batteries are promising candidates for the next generation of energy storage systems owing to their high energy density, low toxicity and abundant reserves of sulfur. However, sulfur has poor conductivity, large volume change during charge/discharge, and more importantly, the intermediate polysulfide (Li2Sn, 3 ≤ n≤8) produced in the cycling process is easily soluble in the electrolyte resulting in the "shuttle effect", which have greatly limited the commercialization of lithium-sulfur batteries. Therefore, it is of great value to develop optimized sulfur cathode materials to improve electrode conductivity, buffer volume change and restrain the diffusion of polysulfide. In this work, we construct a V-MOF (MIL-47) derived V2O3@C hollow microcuboid with a hierarchical lasagna-like structure through hydrothermal synthesis followed by calcination, and employ it as a sulfur host for the first time. The fast anchoring of polysulfide by V2O3 nanoparticles and the high electronic conductivity of the 3D carbon framework can simultaneously inhibit the "shuttle effect" in the charge-discharge process and accelerate the kinetics of the redox process. Moreover, the special lasagna-like structure with appropriate voids generated during calcination not only provides many sites for sulfur loading, but also effectively alleviates the volume expansion problem during the electrochemical reaction. Therefore, the final fabricated sulfur cathode via the melt impregnation method exhibits good cycling stability (62.3% after 1000 cycles at 1C) and rate performance (663 mA h g-1 at 2C) at a relatively high sulfur loading of 3.7 mg cm-2.

Construction of Structure-Tunable Si@Void@C Anode Materials for Lithium-Ion Batteries through Controlling the Growth Kinetics of Resin.

Silicon (Si), a promising candidate for next-generation lithium-ion battery anodes, is still hindered by its volume change issue for (de)lithiation, thus resulting in tremendous capacity fading. Designing carbon-modified Si materials with a void-preserving structure (Si@void@C) can effectively solve this issue. The preparation of Si@void@C, however, usually depended on template-based routes or chemical vapor deposition, which involve toxic reagents, tedious operation processes, and harsh conditions. Here, a facile templateless approach for preparing Si@void@C materials is reported through controlling the growth kinetics of resin, without the use of toxic hydrofluoric acid or harsh conditions. This approach allows great flexibility in tuning the crucial parameters of Si@void@C, such as the carbon shell thickness, the reserved void size, and the number of Si cores coated by a carbon shell. The optimized Si@void@C delivers a large specific capacity (1993.2 mAh g-1 at 0.1 A g-1), excellent rate performance (799.4 mAh g-1 at 10.0 A g-1), and long cycle life (73.5% capacity retention after 1000 cycles at 2.0 A g-1). In addition, a full cell fabricated with a Si@void@C anode and commercial LiFePO4 cathode also displays an impressive cycling performance.

Metal-organic framework derived 3D graphene decorated NaTi2(PO4)3 for fast Na-ion storage.

NASCION-type materials featuring super ionic conductivity are of considerable interest for energy storage in sodium ion batteries. However, the issue of inherent poor electronic conductivity of these materials represents a fundamental limitation in their utilization as battery electrodes. Here, for the first time, we develop a facile strategy for the synthesis of NASICON-type NaTi2(PO4)3/reduced graphene oxide (NTP-rGO) Na-ion anode materials from three-dimensional (3D) metal-organic frameworks (MOFs). The selected MOF serves as an in situ etching template for the titanium resource, and importantly, endows the materials with structure-directing properties for the self-assembly of graphene oxide (GO) through a one-step solvothermal process. Through the subsequent carbonization, an rGO decorated NTP architecture is obtained, which offers fast electron transfer and improved Na+ ion accessibility to active sites. Benefiting from its unique structural merits, the NTP-rGO exhibits improved sodium storage properties in terms of high capacity, excellent rate performance and good cycling life. We believe that the findings of this work provide new opportunities to design high performance NASICON-type materials for energy storage.

Stabilizing the structure of LiMn0.5Fe0.5PO4via the formation of concentration-gradient hollow spheres with Fe-rich surfaces.

LiMnxFe1-xPO4 (LMFP) has attracted extensive interest owing to its high safety and appropriate redox potential. Nevertheless, its poor electrochemical kinetics and structural instability, depending on its manganese content, are still limiting its further application. Herein, we realize a concentration-gradient LiMn0.5Fe0.5PO4 hollow sphere cathode material with a carbon coating (HCG-LMFP/C) by a facile and controllable two-step solvothermal approach. On the one hand, the porous hollow architecture can sustain excellent structural stabilization against the volume changes that occur during repeated Li+ intercalation/deintercalation. On the other hand, the unique concentration-gradient structure with its Fe-rich surface can not only relieve interface deterioration and improve the ionic/electric conductivity due to the active nature of LiFePO4, but also guarantees the chemical stability of the LMFP against electrolyte attack and remarkably reduces Mn dissolution, even at elevated temperature. Therefore, the obtained concentration-gradient HCG-LMFP/C cathode shows improved high-rate performance (111 and 78 mA h g-1 at 20 and 60C rates, respectively) and excellent capacity retention (96% after 1000 cycles at the 10C rate) as well as outstanding temperature tolerance (over a temperature range from 40 °C to -10 °C). More importantly, the present gradient strategy opens up a new window for designing high-performance and stable olivine cathodes, which could also be compatible with many other energy-storage materials for various applications.

Purifying the Phase of NaTi2(PO4)3 for Enhanced Na+ Storage Properties.

Sodium-ion batteries (SIBs) are increasingly on demand owning to their prospect as an inexpensive alternative to Li-ion batteries. However, designing electrode materials with satisfactory rate capacity performance requires high electron transport and Na+ conductivity, which is extremely challenging. Herein, we report a hexadecylamine (HDA)-mediated synthesis of NaTi2(PO4)3 (NTP) electrodes via one-step solvothermal process. The addition of HDA material (1) enables the formation of a carbon coating that improves the electron conductivity and (2) importantly serves as a structure-directing agent reducing the NTP-impurity phases in which the transport of Na+ ions are sluggish. As a result, the synthesized NTP anode delivers superior rate of capacity retention of 77.8% under the 100-fold increase in current densities. Moreover, outstanding specific capacity of 117.9 mAh g-1 at 0.5 C and capacity retention of 88.6% after 1500 cycles at 1 C can be obtained. The findings of this work provide new opportunity to design SIBs electrodes with superior electrical and ionic conductivity.

Effect of Pulse Frequency on Microstructure and Mechanical Properties of 2198 Al-Li Alloy Joints Obtained by Ultrahigh-Frequency Pulse AC CMT Welding.

In this study, 2198 Al-Li alloy, a low density and high-performance material for aerospace equipment, was welded using ultrahigh-frequency pulse alternating current with cold metal transfer (UHF-ACCMT). Influence of different ultrahigh-frequency on the formation, porosity, microstructure, microhardness and tensile strength of the welded joints were investigated. The results showed that the coupled ultrahigh-frequency current generated electromagnetic force to stir the liquid metal of molten pool. The weld formation became much better with metallic luster and uniform ripples at frequency of 60 kHz and 70 kHz. The porosity was the minimum at frequency of 60 kHz. Furthermore, the molten pool was scoured and stirred by the electromagnetic force which provided the thermal and dynamic conditions for nucleation and grain refinement, the width of fine equiaxed grain zone became larger, and the number of equiaxed non-dendrite grains increased. With the grain refining and crystallize transition, the average microhardness and tensile strength of the joints at frequency of 60 kHz reached up the highest value, 116 HV0.1 and 338 MPa, respectively. The fracture of the welded joints presented the characteristics of quasi-cleavage fracture.

Biorefining of rice straw by sequential fermentation and anaerobic digestion for bioethanol and/or biomethane production: Comparison of structural properties and energy output.

Three routes; namely R1 representing direct anaerobic digestion (AD), R2 representing enzymatic hydrolysis followed by fermentation, distillation, then AD, and R3 representing AD of fermentation broth without distillation; of alkali pretreated rice straw were investigated. Results showed that sequential fermentation and AD effectively enhanced fibers degradation with significant changes in the composition. Fermentation through R2 resulted in ethanol yield of 87.4 g kg-1 dry straw. Maximum biogas yields of 286.9, 233.3 and 372.4 L kg-1 VS were recorded by AD for R1, R2 and R3 after reaching the steady state at 36, 24 and 33 days, respectively. However, biogas produced through R3 showed the highest significant biomethane content (79.3%) which represented 15 and 8% higher than that of R1 and R2, respectively. Therefore, the highest bioenergy output and energy conversion efficiency of 10.58 GJ ton-1 and 75.6%, respectively, were obtained through R3 demonstrating the positive effect of fermentation prior to AD.

A study on LiFePO4/graphite cells with built-in Li4Ti5O12 reference electrodes.

In this work, based on the superior electrochemical stability of Li4Ti5O12 (LTO) electrodes, LiFePO4 (LFP)/graphite cells with built-in LTO electrodes as reference electrodes were designed and fabricated. The characteristics of the LTO reference electrodes in the fabricated lithium-ion cells were measured and discussed. The experimental data demonstrated that the LTO built-in reference electrodes were simple to prepare and were feasible options for long-term in situ monitoring of the development of potentials and other electrochemical parameters, such as the Li+ diffusion coefficient (D Li) and electrochemical impedance spectroscopy (EIS) information, for both anodes and cathodes. Moreover, it is believed that the adoption of LTO as a reference electrode could be of great significance for long-term monitoring of the charge and discharge behavior of individual electrodes in other kinds of lithium-ion cells.

Two-step gasification of cattle manure for hydrogen-rich gas production: Effect of biochar preparation temperature and gasification temperature.

Two-step gasification process was proposed to dispose cattle manure for hydrogen rich gas production. The effect of temperature on product distribution and biochar properties were first studied in the pyrolysis-carbonization process. The steam gasification of biochar derived from different pyrolysis-carbonization temperatures was then performed at 750°C and 850°C. The biochar from the pyrolysis-carbonization temperatures of 500°C had high carbon content and low volatiles content. According to the results of gasification stage, the pyrolysis-carbonization temperature of 500°C and the gasification temperature of 850°C were identified as the suitable conditions for hydrogen production. We obtained 1.61m3/kg of syngas production, 0.93m3/kg of hydrogen yield and 57.58% of hydrogen concentration. This study shows that two-step gasification is an efficient waste-to-hydrogen energy process.