Constructing Matching Cathode-Anode Interphases with Improved Chemo-mechanical Stability for High-Energy Batteries.

Coupling Ni-rich layered oxide cathodes with Si-based anodes is one of the most promising strategies to realize high-energy-density Li-ion batteries. However, unstable interfaces on both cathode and anode sides cause continuous parasitic reactions, resulting in structural degradation and capacity fading of full cells. Herein, lithium tetrafluoro(oxalato) phosphate is synthesized and applied as a multifunctional electrolyte additive to mitigate irreversible volume swing of the SiOx anode and suppress undesirable interfacial evolution of the LiNi0.83Co0.12Mn0.05O2 (NCM) cathode simultaneously, resulting in improved cycle life. Benefiting from its desirable redox thermodynamics and kinetics, the molecularly tailored additive facilitates matching interphases consisting of LiF, Li3PO4, and P-containing macromolecular polymer on both the NCM cathode and SiOx anode, respectively, modulating interfacial chemo-mechanical stability as well as charge transfer kinetics. More encouragingly, the proposed strategy enables 4.4 V 21700 cylindrical batteries (5 Ah) with excellent cycling stability (92.9% capacity retention after 300 cycles) under practical conditions. The key finding points out a fresh perspective on interfacial optimization for high-energy-density battery systems.

The Effects of Cognitive Control on the Subcomponents of Language Control in Spoken and Written Productions.

AIMS: The present study aimed to investigate whether and how the subcomponents of language control during spoken and written productions were modulated by cognitive control. METHOD: In the current study, unbalanced Chinese-English bilinguals were recruited from a convenience sample at a university to complete the cued language naming task in spoken production and written production, which measured the local language control (as indexed by language switch costs) and the global language control (as indexed by language mixing costs and reversed language dominance effect). In addition, all the participants performed the Simon task, which measured their general inhibitory control ability by calculating the Simon effect, and performed the AX-CPT task to measure their reactive/proactive control preference by calculating their BSI score. All the data were collected using E-prime 2.0 and analyzed in R. Linear mixed-effect model analyses were conducted to reveal the similarities and differences between spoken production and written production for the first-step analysis. Then, the Simon effect and BSI scores were inserted into the mixed-effect models of the switch costs and mixing costs in spoken production and written production, respectively, to explore whether cognitive control can predict the subcomponents of bilingual control. RESULTS: The results showed similar symmetrical switch costs in spoken and written modalities. In contrast, there was a reversed language dominance effect (in the mixed language context) and asymmetrical mixing costs in spoken production but neither in written production. Furthermore, we found that the Simon effect significantly negatively predicted the L2 mixing costs in spoken production, whereas the BSI score significantly negatively predicted both the L1 and L2 mixing costs in written production. CONCLUSION: The findings indicated that, for unbalanced bilinguals, local language control is shared between two modalities, while global language control is modality-independent between spoken production and written production. More importantly, the findings also suggested that global language control in spoken production relies more on the individuals' general inhibitory control, while in written production, it relies more on their cognitive control strategy. Global language control in spoken and written productions separately engages specific aspects of cognitive control, which may account for different forms of processing in global language control between speaking and writing.

Study on the Microclimate Effect of Water Body Layout Factors on Campus Squares.

Quantifying the water layout factors in a campus square helps to lay out water bodies more scientifically and utilize the microclimate effect to alleviate the heat and humidity of campus squares in summer. The West Gate Square of Fujian Agriculture and Forestry University in China has been used as the primary theoretical model, and the landscape pattern index from landscape ecology has been used to quantify the scale, shape, and dispersion of water bodies. Consider the typical weather, the summer solstice, as the experiment time. The relationship between the water body layout factors and cooling effect, the humidification effect, and the wind speed is clarified from both temporal and spatial perspectives. The data were analyzed with ENVI-met and Arcgis software. Then, the optimum campus square water body layout mode was concluded. The results show that: (1) The scale, dispersion, and shape of the water body has a significant effect on the campus temperature and humidity, while the effect on wind speed is not significant. (2) From the cooling and humidifying effect, the ranking of the regulating ability of the water body layout factors is scale > shape > dispersion; the ranking of the influence range is shape > scale > dispersion. (3) When the boundary of the square is determined, the optimum water body layout mode is that the water body area accounts for 36% of the total square area. The shape of the water body is concentrated and not dispersed square. When the water body layout is determined, the optimum layout mode of the boundary is length:width = 1:2.

Research Progress and Hotspot Evolution Analysis of Landscape Microclimate: Visual Analysis Based on CNKI and WOS.

With the increasing requirements of healthy habitat environments, landscape microclimates have been widely concerned. To comprehensively grasp the development history and research status of the landscape microclimates in China and other countries, CiteSpace software was used to comparatively analyze and visually present the literature related to landscape microclimates in CNKI and WOS databases for the past 20 years. The results show that: (1) The number of publications on landscape microclimate research shows an increasing trend in China and other countries, and the number of publications increased significantly after 2016. Although the number of publications by Chinese scholars is less than that of foreign scholars, they have developed rapidly in recent years, and their international influence has increased significantly. (2) A positive exchange has been formed among international scholars, and the number of collaborative studies has been increasing. China's microclimate research has formed relatively stable teams that have conducted numerous studies in the fields of urban communities, street greening, and plant communities, respectively. Although the links between research teams and institutions in China and other countries are relatively close, they still need to be further strengthened. (3) In the past decade, the theoretical system of landscape microclimates has been improved, and the research themes have become more concentrated, but it still has remained close to the early basic research. (4) Future research will remain centered on "mitigating the urban heat island effect" and "optimizing human heat perception". New topics such as "biodiversity", "carbon cycle", and "climate change" have been added. In conclusion, the research needs to continue to explore the evaluation system of microclimates and verify the evaluation index of outdoor thermal comfort for human thermal adaptation in different regions. The standards and systems of human habitat adapted to different regional characteristics should be formed.

Quantitatively analyzing the failure processes of rechargeable Li metal batteries.

Practical use of lithium (Li) metal for high­energy density lithium metal batteries has been prevented by the continuous formation of Li dendrites, electrochemically isolated Li metal, and the irreversible formation of solid electrolyte interphases (SEIs). Differentiating and quantifying these inactive Li species are key to understand the failure mode. Here, using operando nuclear magnetic resonance (NMR) spectroscopy together with ex situ titration gas chromatography (TGC) and mass spectrometry titration (MST) techniques, we established a solid foundation for quantifying the evolution of dead Li metal and SEI separately. The existence of LiH is identified, which causes deviation in the quantification results of dead Li metal obtained by these three techniques. The formation of inactive Li under various operating conditions has been studied quantitatively, which revealed a general "two-stage" failure process for the Li metal. The combined techniques presented here establish a benchmark to unravel the complex failure mechanism of Li metal.

Visualizing the growth process of sodium microstructures in sodium batteries by in-situ 23Na MRI and NMR spectroscopy.

The growth of sodium dendrites and the associated solid electrolyte interface (SEI) layer is a critical and fundamental issue influencing the safety and cycling lifespan of sodium batteries. In this work, we use in-situ 23Na magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) techniques, along with an innovative analytical approach, to provide space-resolved and quantitative insights into the formation and evolution of sodium metal microstructures (SMSs; that is, dendritic and mossy Na metal) during the deposition and stripping processes. Our results reveal that the growing SMSs give rise to a linear increase in the overpotential until a transition voltage of 0.15 V is reached, at which point violent electrochemical decomposition of the electrolyte is triggered, leading to the formation of mossy-type SMSs and rapid battery failure. In addition, we determined the existence of NaH in the SEI on sodium metal with ex-situ NMR results. The poor electronic conductivity of NaH is beneficial for the growth of a stable SEI on sodium metal.

High-Efficiency Lithium Metal Anode Enabled by a Concentrated/Fluorinated Ester Electrolyte.

Lithium (Li) metal anode (LMA) has received growing attention due to its highest theoretical capacity (3860 mA h g-1) and lowest redox potential (-3.04 V versus standard hydrogen electrode). However, practical application of LMA is obstructed by the detrimental side reactions between Li metal and organic electrolytes, especially when cycled in traditional carbonate ester electrolytes. Herein, we propose a novel fluorinated carbonate ester-based electrolyte by combining diethyl fluorocarbonate (ETFEC) solvent and 5 M LiFSI concentration (M = mol L-1). Using this electrolyte, an ultrahigh Li plating/stripping Coulombic efficiency (CE) of 99.1% can be obtained in Li||Cu cells and a stable cycle performance of Li||LiFePO4 is achieved under the conditions of limited Li metal (5 mA h cm-2), moderate loading LiFePO4 (7-8 mg cm-2), and lean electrolyte (40 uL). The fundamental functioning mechanism of this novel electrolyte has been carefully investigated by scanning electronic microscopy (SEM), operando optical microscopy (OM), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and solid state nuclear magnetic resonance (SS-NMR). The results demonstrate that this optimized electrolyte facilitates formation of a high Li+ conductive SEI layer enriched with LiF and inorganic sulfur-containing species, which can effectively suppress the side reactions between electrolyte and Li metal and prevent formation of dead Li.

Scalable Engineering of Bulk Porous Si Anodes for High Initial Efficiency and High-Areal-Capacity Lithium-Ion Batteries.

Nano-Si has been long-hampered in its use for practical lithium battery anodes due to its intrinsic high surface area. To improve the Coulombic efficiency and areal mass loading, we extend the starting materials from nano-Si to photovoltaic waste Si powders (∼1.5 µm). Unique morphology design and interfacial engineering are designed to overcome the particle fracture of micrometer Si. First, we develop a Cu-assisted chemical wet-etching method to prepare micrometer-size bulk-porous Si (MBPS), which provides interconnected porous space to accommodate volume expansion. In addition, a monolithic, multicore, interacting MBPS/carbonized polyacrylonitrile (c-PAN) electrode with strong interfacial Si-N-C is designed to improve the interparticle electrical conductivity during volume expansion and shrinkage. Furthermore, intermediate Si nanocrystals are well-maintained during the lithiation of MBPS, which facilitates the reversibility of lithiation-delithiation process. As a result, the MBPS/c-PAN electrodes exhibit a reversible specific capacity of 2126 mAh g-1 with a high initial Coulombic efficiency of 92%. Moreover, even after increasing the capacity loading to 3.4 mAh cm-2, the well-designed electrode shows a capacity retention of 94% in the first 50 cycles at a current density of 0.2 A g-1 with deep lithiation and delithiation processes between 0.005 and 2.5 V.

Insights into the Electrochemical Reaction Mechanism of a Novel Cathode Material CuNi2(PO4)2/C for Li-Ion Batteries.

In this work, we first report the composite of CuNi2(PO4)2/C (CNP/C) can be employed as the high-capacity conversion-type cathode material for rechargeable Li-ion batteries (LIBs), delivering a reversible capacity as high as 306 mA h g-1 at a current density of 20 mA g-1. Furthermore, CNP/C also presents good rate performance and reasonable cycling stability based on a nontraditional conversion reaction mode. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) characterizations show that CNP is reduced to form Cu/Ni and Li3PO4 during the discharging process, which is reversed in the following charging process, demonstrating that a reversible conversion reaction mechanism occurs. X-ray absorption spectroscopy (XAS) discloses that Ni2+/Ni0 exhibits a better reversibility compared to Cu2+/Cu during the conversion reaction process, while Cu0 is more difficult to be reoxidized during the recharge process, leading to capacity loss as a consequence. The fundamental understanding obtained in this work provides some important clues to explore the high-capacity conversion-type cathode materials for rechargeable LIBs.

Exploring Highly Reversible 1.5-Electron Reactions (V3+/V4+/V5+) in Na3VCr(PO4)3 Cathode for Sodium-Ion Batteries.

The development of highly reversible multielectron reaction per redox center in sodium super ionic conductor-structured cathode materials is desired to improve the energy density of sodium-ion batteries. Here, we investigated more than one-electron storage of Na in Na3VCr(PO4)3. Combining a series of advanced characterization techniques such as ex situ 51V solid-state nuclear magnetic resonance, X-ray absorption near-edge structure, and in situ X-ray diffraction, we reveal that V3+/V4+ and V4+/V5+ redox couples in the materials can be accessed, leading to a 1.5-electron reaction. It is also found that a light change on the local electronic and structural states or phase change could be observed after the first cycle, resulting in the fast capacity fade at room temperature. We also showed that the irreversibility of the phase changes could be largely suppressed at low temperature, thus leading to a much improved electrochemical performance.