Large-Scale Fabrication of Stable Silicon Anode in Air for Sulfide Solid State Batteries via Ionic-Electronic Dual Conductive Binder.

The construction of a continuous ionic/electronic pathway is critical for Si-based sulfide all-solid-state batteries (ASSBs) with the advantages of high-energy density and high-cycle stability. However, a significant impediment arises from the parasitic reaction occurring between the ionic sulfide solid-state electrolyte (S-SE) and electronic carbon additive, posing a formidable challenge. Additionally, the fabrication of electrodes necessitates stringent operational conditions, further limiting practical applicability. Herein, we report an ionic-electronic dual conductive binder for the fabrication of robust silicon anode under ambient air conditions in the absence of high-cost and air-sensitive S-SE for ASSBs. This binder incorporates in-situ reduced silver nanoparticles (AgNPs) into a high-strength polymer rich in ether bonds, establishing a conductive pathway for lithium ions and electrons. With the binder-composited Si anode, the half-cell exhibits a remarkable capacity of 1906.9 mAh g-1 and stable cycling for 500 cycles at a current density of 2 C (4.4 mA cm-2) under a low stack pressure of 5 MPa. The full cell using Ni0.9Co0.075Mn0.025O2 (NCM90) exhibits a remark cycling stability within 2,000 cycles at 5 C (8 mA cm-2). This work presents an inspired design of functional binders for large-scale manufacture and mild operation in a low-cost way for Si anodes in ASSBs. This article is protected by copyright. All rights reserved.

Synergetic regulation of SEI mechanics and crystallographic orientation for stable lithium metal pouch cells.

The advancement of Li-metal batteries is significantly impeded by the presence of unstable solid electrolyte interphase and Li dendrites upon cycling. Herein, we present an innovative approach to address these issues through the synergetic regulation of solid electrolyte interphase mechanics and Li crystallography using yttrium fluoride/polymethyl methacrylate composite layer. Specifically, we demonstrate the in-situ generation of Y-doped lithium metal through the reaction of composite layer with Li metal, which reduces the surface energy of the (200) plane, and tunes the preferential crystallographic orientation to (200) plane from conventional (110) plane during Li plating. These changes effectively passivate Li metal, thereby significantly reducing undesired side reactions between Li and electrolytes by 4 times. Meanwhile, the composite layer with suitable modulus (~1.02 GPa) can enhance mechanical stability and maintain structural stability of SEI. Consequently, a 4.2 Ah pouch cell with high energy density of 468 Wh kg-1 and remarkable capacity stability of 0.08% decay/cycle is demonstrated under harsh condition, such as high-areal-capacity cathode (6 mAh cm-2), lean electrolyte (1.98 g Ah-1), and high current density (3 mA cm-2). Our findings highlight the potential of reactive composite layer as a promising strategy for the development of stable Li-metal batteries.

Energy harvesting from water impact using piezoelectric energy harvester.

Energy, as an indispensable part of human life, has been a hot topic of research among scholars. The water kinetic energy generated by ocean currents, as a kind of clean energy, has high utilization rate, high power generation potential, and a broad prospect of powering microelectronic devices. As a result, the water kinetic piezoelectric energy harvester (WKPEH) has made significant progress in powering ocean sensors by harvesting ocean currents. This paper provides a comprehensive review of technologies that have been used in recent years to harvest energy from marine fluids using WKPEH. Detailed study of the energy harvesting mechanism of WKPEH. WKPEH can use the flutter-induced vibrations, vortex-induced vibrations, and wake oscillation principles to harvest water kinetic energy. The structural characteristics and output performance of each mechanism are also discussed and compared, and finally, a prospect on WKPEH is given.

Anomalous thermal activation of green upconversion luminescence in Yb/Er/ZnGdO self-assembled microflowers for high-sensitivity temperature detection.

Non-contact optical temperature detection has shown a great promise in biological systems and microfluidics because of its outstanding spatial resolution, superior accuracy, and non-invasive nature. However, the thermal quenching of photoluminescence significantly hinders the practical applications of optical temperature probes. Herein, we report thermally enhanced green upconversion luminescence in Yb/Er/ZnGdO microflowers by a defect-assisted thermal distribution mechanism. A 1.6-fold enhancement in green emission was demonstrated as the temperature increased from 298 K to 558 K. Experimental results and dynamic analysis demonstrated that this behavior of thermally activating green upconversion luminescence originates from the emission loss compensation, which is attributed to thermally-induced energy transfer from defect levels to the green emitting level. In addition, the Yb/Er/ZnGdO microflowers can act as self-referenced radiometric optical thermometers. The ultrahigh absolute sensitivity of 1.61% K-1 and an excellent relative sensitivity of 15.5% K-1 based on the 4F9/2/2H11/2(2) level pair were synchronously achieved at room temperature. These findings provide a novel strategy for surmounting the thermal quenching luminescence, thereby greatly promoting the application of non-contact sensitive radiometric thermometers.

Design and Manufacturing of a Novel Trabecular Tibial Implant.

The elastic modulus of traditional solid titanium alloy tibial implants is much higher than that of human bones, which can cause stress shielding. Designing them as a porous structure to form a bone-like trabecular structure effectively reduces stress shielding. However, the actual loading conditions of bones in different parts of the human body have not been considered for some trabecular structures, and their mechanical properties have not been considered concerning the personalized differences of other patients. Therefore, based on the elastic modulus of the tibial stem obtained from Quantitative Computed Tomography (QCT) imaging between 3.031 and10.528 GPa, and the load-bearing state of the tibia at the knee joint, a porous structure was designed under compressive and shear loading modes using topology optimization. Through comprehensive analysis of the mechanical and permeability properties of the porous structure, the results show that the Topology Optimization-Shear-2 (TO-S2) structure has the best compressive, shear mechanical properties and permeability and is suitable as a trabecular structure for tibial implants. The Gibson-Ashby model was established to control the mechanical properties of porous titanium alloy. A gradient filling of porous titanium alloy with a strut diameter of 0.106-0.202 mm was performed on the tibial stem based on the elastic modulus range, achieving precise matching of the mechanical properties of tibial implants and closer to the natural structure than uniformly distributed porous structures in human bones. Finally, the new tibial implant was printed by selective laser melting (SLM), and the molding effect was excellent.

Climate warming negatively affects plant water-use efficiency in a seasonal hydroperiod wetland.

Climate warming has substantial influences on plant water-use efficiency (PWUE), which is defined as the ratio of plant CO2 uptake to water loss and is central to the cycles of carbon and water in ecosystems. However, it remains uncertain how does climate warming affect PWUE in wetland ecosystems, especially those with seasonally alternating water availability during the growing season. In this study, we used a continuous 10-year (2011-2020) eddy covariance (EC) dataset from a seasonal hydroperiod wetland coupled with a 15-year (2003-2017) satellite-based dataset (called PML-V2) and an in situ warming experiment to examine the climate warming impacts on wetland PWUE. The 10-year EC observational results revealed that rising temperatures had significant negative impacts on the interannual variations in wetland PWUE, and increased transpiration (Et) rather than changes in gross primary productivity (GPP) dominated these negative impacts. Furthermore, the 15-year satellite-based evidence confirmed that, in the study region, climate warming had significant negative consequences for the interannual variations in wetland PWUE by enhancing wetland Et. Lastly, at the leaf-scale, the light response curves of leaf photosynthesis, leaf Et, and leaf-scale PWUE indicated that wetland plants need to consume more water during the photosynthesis process under warmer conditions. These findings provide a fresh perspective on how climate warming influences carbon and water cycles in wetland ecosystems.

Tailoring the p-Band Center of NS Pair for Accelerating High-Performance Lithium-Oxygen Battery.

The local coordination environment of catalytical moieties directly determines the performance of electrochemical energy storage and conversion devices, such as Li-O2 batteries (LOBs) cathode. However, understanding how the coordinative structure affects the performance, especially for non-metal system, is still insufficient. Herein, a strategy that introduces S-anion to tailor the electronic structure of nitrogen-carbon catalyst (SNC) is proposed to improve the LOBs performance. This study unveils that the introduced S-anion effectively manipulates the p-band center of pyridinic-N moiety, substantially reducing the battery overpotential by accelerating the generation and decomposition of intermediate products Li1-3 O4 . The lower adsorption energy of discharging product Li2 O2 on NS pair accounts for the long-term cyclic stability by exposing the high active area under operation condition. This work demonstrates an encouraging strategy to enhance LOBs performance by modulating the p-band center on non-metal active sites.

Design of a Novel Trabecular Acetabular Cup and Selective Laser Melting Fabrication.

The acetabular cups used in total hip arthroplasty are mostly made of dense metal materials with an elastic moduli much higher than that of human bone. This leads to stress shielding after implantation, which may cause aseptic loosening of the implant. Selective laser melting (SLM) technology allows us to produce tiny and complex porous structures and to reduce the elastic moduli of dense metals, thereby avoiding stress shielding. In the present study, rhombic dodecahedron porous structures with cell sizes of 1 mm, 1.5 mm, and 2 mm were designed. The strut diameter was changed to ensure that the porosity and pore size would meet the bone ingrowth requirements. Then, porous Ti6Al4V alloy specimens were printed using SLM, and compressive tests were carried out. The results showed that the compressive strength and elastic modulus values of the specimens with a cell size of 1.5 mm were in the range of 78.16-242.94 MPa and 1.74-4.17 GPa, respectively, which are in line with the mechanical properties of human cortical bone. Finite element analysis of a total hip joint model was carried out to simulate gait, and the surface of the trabecular acetabular cup was divided into 10 regions according to the stress distribution, with the stress interval in the range of 37.44-219.24 MPa. According to the compression test results, the gradient structure of Ti6Al4V alloy with different porosity was designed for trabecular coating. The gradient porous structure meets the mechanical requirements and is closer to the natural structure of human bone than the uniformly distributed porous structure.

Single-Atom Tailored Hierarchical Transition Metal Oxide Nanocages for Efficient Lithium Storage.

Mitigating the mechanical degradation and enhancing the ionic/electronic conductivity are critical but challengeable issues toward improving electrochemical performance of conversion-type anodes in rechargeable batteries. Herein, these challenges are addressed by constructing interconnected 3D hierarchically porous structure synergistic with Nb single atom modulation within a Co3 O4 nanocage (3DH-Co3 O4 @Nb). Such a hierarchical-structure nanocage affords several fantastic merits such as rapid ion migration and enough inner space for alleviating volume variation induced by intragrain stress and optimized stability of the solid-electrolyte interface. Particularly, experimental studies in combination with theoretical analysis verify that the introduction of Nb into the Co3 O4 lattice not only improves the electron conductivity, but also accelerates the surface/near-surface reactions defined as pesudocapacitance behavior. Dynamic behavior reveals that the ensemble design shows huge potential for fast and large lithium storage. These features endow 3DH-Co3 O4 @Nb with remarkable battery performance, delivering ≈740 mA h g-1 after ultra-long cycling of 1000 times under a high current density of 5 A g-1 . Importantly, the assembled 3DH-Co3 O4 @Nb//LiCoO2 pouch cell also presents a long-lived cycle performance with only ≈0.059% capacity decay per cycle, inspiring the design of electrode materials from both the nanostructure and atomic level toward practical applications.

Experimental warming reduces ecosystem resistance and resilience to severe flooding in a wetland.

Climate warming and extreme hydrological events are threatening the sustainability of wetlands across the globe. However, whether climate warming will amplify or diminish the impact of extreme flooding on wetland ecosystems is unknown. Here, we show that climate warming significantly reduced wetland resistance and resilience to a severe flooding event via a 6-year warming experiment. We first found that warming rapidly altered plant community structure by increasing the dominance of low-canopy species. Then, we showed that warming reduced the resistance and resilience of vegetation productivity to a 72-cm flooding event. Last, we detected slower postflooding carbon processes, such as gross ecosystem productivity, soil respiration, and soil methane emission, under the warming treatment. Our results demonstrate how severe flooding can destabilize wetland vegetation structure and ecosystem function under climate warming. These findings indicate an enhanced footprint of extreme hydrological events in wetland ecosystems in a warmer climate.

Warming reshaped the microbial hierarchical interactions.

Global warming may alter microbially mediated ecosystem functions through reshaping of microbial diversity and modified microbial interactions. Here, we examined the effects of 5-year experimental warming on different microbial hierarchical groups in a coastal nontidal soil ecosystem, including prokaryotes (i.e., bacteria and archaea), fungi, and Cercozoa, which is a widespread phylum of protists. Warming significantly altered the diversity and structure of prokaryotic and fungal communities in soil and additionally decreased the complexity of the prokaryotic network and fragmented the cercozoan network. By using the Inter-Domain Ecological Network approach, the cross-trophic interactions among prokaryotes, fungi, and Cercozoa were further investigated. Under warming, cercozoan-prokaryotic and fungal-prokaryotic bipartite networks were simplified, whereas the cercozoan-fungal network became slightly more complex. Despite simplification of the fungal-prokaryotic network, the strengthened synergistic interactions between saprotrophic fungi and certain prokaryotic groups, such as the Bacteroidetes, retained these phyla within the network under warming. In addition, the interactions within the fungal community were quite stable under warming conditions, which stabilized the interactions between fungi and prokaryotes or protists. Additionally, we found the microbial hierarchical interactions were affected by environmental stress (i.e., salinity and pH) and soil nutrients. Interestingly, the relevant microbial groups could respond to different soil properties under ambient conditions, whereas under warming these two groups tended to respond to similar soil properties, suggesting network hub species responded to certain environmental changes related to warming, and then transferred this response to their partners through trophic interactions. Finally, warming strengthened the network modules' negative association with soil organic matters through some fungal hub species, which might trigger soil carbon loss in this ecosystem. Our study provides new insights into the response and feedback of microbial hierarchical interactions under warming scenario.

Reduced magnitude and shifted seasonality of CO2 sink by experimental warming in a coastal wetland.

Coastal wetlands have the highest carbon sequestration rate per unit area among all unmanaged natural ecosystems. However, how the magnitude and seasonality of the CO2 sink in coastal wetlands will respond to future climate warming remains unclear. Here, based on measurements of ecosystem CO2 fluxes in a field experiment in the Yellow River Delta, we found that experimental warming (i.e., a 2.4°C increase in soil temperature) reduced net ecosystem productivity (NEP) by 23.7% across two growing seasons of 2017-2018. Such a reduction in NEP resulted from the greater decrease in gross primary productivity (GPP) than ecosystem respiration (ER) under warming. The negative warming effect on NEP mainly occurred in summer (-43.9%) but not in autumn (+61.3%), leading to a shifted NEP seasonality under warming. Further analyses showed that the warming effects on ecosystem CO2 exchange were mainly controlled by soil salinity and its corresponding impacts on species composition. For example, warming increased soil salinity (+35.0%), reduced total aboveground biomass (-9.9%), and benefited the growth of plant species with high salt tolerance and late peak growth. To the best of our knowledge, this study provides the first experimental evidence on the reduced magnitude and shifted seasonality of CO2 exchange under climate warming in coastal wetlands. These findings underscore the high vulnerability of wetland CO2 sink in coastal regions under future climate change.

Unraveling the Promotion Effects of a Soluble Cobaltocene Catalyst with Respect to Li-O2 Battery Discharge.

The discharge process of a nonaqueous Li-O2 battery at the cathode is the direct oxygen reduction reaction (ORR) with the formation of discharge product, e.g., Li2O2, deposits on the cathode surface. The aggressive superoxide intermediate generated during the ORR severely degrades the organic electrolyte and carbon-based cathodes. To avoid the formation of superoxide species and promote the growth of Li2O2 in the electrolyte solution, we employ a soluble cobaltocene [Co(C5H5)2, Cp2Co] as a homogeneous molecule catalyst to boost the discharge performance of Li-O2 batteries. Owing to the unique chemical reactivity of Cp2Co with molecular oxygen, the electrochemistry of the discharge process at the cathode is the (Cp2Co)2II-O22- adduct-mediated process rather than direct electrochemical oxygen reduction, thereby avoiding the formation of aggressive superoxide intermediate. In addition, the strong intermolecular attraction between Cp2Co and the newly formed Li2O2 promotes the solution phase growth of Li2O2, which effectively suppresses electrode passivation.

Bifunctional LaMn0.3Co0.7O3 Perovskite Oxide Catalyst for Oxygen Reduction and Evolution Reactions: The Optimized eg Electronic Structures by Manganese Dopant.

Perovskite oxides as bifunctional electrocatalysts toward oxygen reduction (ORR) and oxygen evolution reactions (OER) have been investigated for decades because of the flexible and adjustable electronic structures. For example, by optimizing the strength of the Co-O bond, the ORR and OER activity of a typical perovskite oxide, LaCoO3, can be improved, but they are still unsatisfying. The insufficient insights into the effects of secondary metal dopants at the B-site on the electronic structure and activity, especially for ORR, significantly limit the R&D of bifunctional perovskite oxide catalysts. In this work, a series of LaMnxCo1-xO3 (x = 0, 0.25, 0.3, 0.35, 0.5, 1) catalysts are prepared by a polyol-assisted solvothermal method to investigate the structure-property relationships between the B-site metal substitution and the electrochemical performance of perovskite oxides catalysts. The optimized LaMn0.3Co0.7O3 catalyst demonstrates an enhanced half-wave potential of 0.72 V for ORR, 52 mV higher than that of the pristine LaCoO3 (0.668 V). Meanwhile, the OER overpotential of LaMn0.3Co0.7O3 catalyst is 416 mV, which is reduced by 64 mV compared to LaCoO3 (480 mV). It is revealed that the appropriate Mn dopant efficiently optimizes the covalency of Co-O bonds and significantly reduces the eg orbit-filling electron from 1.23 of pristine LaCoO3 to 1.02 in LaMn0.3Co0.7O3 (very close to theoretical value 1). This work paves a new way to design and synthesize bifunctional perovskite oxide electrocatalyst for ORR and OER.

Perovskite LaCoxMn1-xO3-σ with Tunable Defect and Surface Structures as Cathode Catalysts for Li-O2 Batteries.

Rechargeable lithium-oxygen batteries have shown great potential as next-generation sustainable and green energy storage systems. The bifunctional catalyst plays an important role in accelerating the cathode kinetics for practical realization of the batteries. Herein, we employ the surface structure and defect engineering to introduce surface-roughened nanolayers and oxygen vacancies on the mesoporous hollow LaCoxMn1-xO3-σ perovskite catalyst by in situ cation substitution. The experimental results show that the O2-electrode with the LaCo0.75Mn0.25O3-σ catalyst exhibits an extremely high discharge capacity of 10,301 mA h g-1 at 200 mA g-1 for the initial cycle and superior cycling stability under a capacity limit of 500 mA h g-1 together with a low voltage gap of 1.12 V. Good electrochemical performance of LaCo0.75Mn0.25O3-σ can be attributed to the synergistic effect of the hierarchical mesoporous hollow structure and the abundant oxygen vacancies all over the catalyst surface. We reveal that the modified surface structure can provide more accessibility of active sites to promote electrochemical reactions, and the introduced oxygen vacancy can serve as an efficient substrate for binding intermediate products and decomposition reactions of Li2O2 during discharge and charge processes. Our methodology provides meaningful insights into the rational design of highly active perovskite catalysts in energy storage/conversion systems.