Volume Expansion Research Articles

Stress-Dispersed Nanoconstruction of CoMoP Anode: Improved Na-Storage Stability and Reversibility.

Metal phosphide anode materials encounter poor reversibility of the discharge product (metal and Na3P) and large volume variation, resulting in low initial Coulombic efficiency (ICE) and severe capacity degradation. Herein, a bimetallic phosphide (CoMoP) with three-dimensional ordered porous (3DOP) nanoconstruction was fabricated, which presents a reduced Gibbs free energy change (ΔG) of redox reaction between Co-Mo/Na3P and CoMoP and improved conductivity compared to CoP and MoP. Additionally, the 3DOP architecture could disperse stress and reduce strain during cycling, thus improving structural stability of CoMoP. In situ and ex situ characterizations and electrochemical measurements suggest that 3DOP CoMoP exhibits highly reversible sodium storage with an ICE of 58% at 0.1 A g-1, enhanced reaction dynamics, and good cycling stability with around 0.04% capacity decay per cycle at 1 A g-1 after 1000 cycles. Consequently, this work offers a new perspective to solve issues of reversibility of redox chemistry and volume expansion for secondary batteries.

Multi-Scenario Simulation of Land Use and Assessment of Carbon Stocks in Terrestrial Ecosystems Based on SD-PLUS-InVEST Coupled Modeling in Nanjing City

In the context of achieving the goal of carbon neutrality, exploring the changes in land demand and ecological carbon stocks under future scenarios at the urban level is important for optimizing regional ecosystem services and developing a land-use structure consistent with sustainable development strategies. We propose a framework of a coupled system dynamics (SD) model, patch generation land-use simulation (PLUS) model, and integrated valuation of ecosystem services and trade-offs (InVEST) model to dynamically simulate the spatial and temporal changes of land use and land-cover change (LUCC) and ecosystem carbon stocks under the NDS (natural development scenario), EPS (ecological protection scenario), RES (rapid expansion scenario), and HDS (high-quality development scenario) in Nanjing from 2020 to 2040. From 2005 to 2020, the expansion rate of construction land in Nanjing reached 50.76%, a large amount of ecological land shifted to construction land, and the ecological carbon stock declined dramatically. Compared with 2020, the ecosystem carbon stocks of the EPS and HDS increased by 2.4 × 106 t and 1.5 × 106 t, respectively, with a sizable ecological effect. It has been calculated that forest and cultivated land are the two largest carbon pools in Nanjing, and the conservation of both is decisive for the future carbon stock. It is necessary to focus on enhancing the carbon stock of forest ecosystems while designating differentiated carbon sink enhancement plans based on the characteristics of other land types. Fully realizing the carbon sink potential of each ecological functional area will help Nanjing achieve its carbon neutrality goal. The results of the study not only reveal the challenges of ecological conservation in Nanjing but also provide useful guidance for enhancing the carbon stock of urban terrestrial ecosystems and formulating land-use planning in line with sustainable development strategies.

Substantial oxygen loss and chemical expansion in lithium-rich layered oxides at moderate delithiation.

Delithiation of layered oxide electrodes triggers irreversible oxygen loss, one of the primary degradation modes in lithium-ion batteries. However, the delithiation-dependent mechanisms of oxygen loss remain poorly understood. Here we investigate the oxygen non-stoichiometry in Li1.18-xNi0.21Mn0.53Co0.08O2-δ electrodes as a function of Li content by using cycling protocols with long open-circuit voltage steps at varying states of charge. Surprisingly, we observe substantial oxygen loss even at moderate delithiation, corresponding to 2.5, 4.0 and 7.6 ml O2 per gram of Li1.18-xNi0.21Mn0.53Co0.08O2-δ after resting at upper capacity cut-offs of 135, 200 and 265 mAh g-1 for 100 h. Our observations suggest an intrinsic oxygen instability consistent with predictions of high oxygen activity at intermediate potentials versus Li/Li+. In addition, we observe a large chemical expansion coefficient with respect to oxygen non-stoichiometry, which is about three times greater than those of classical oxygen-deficient materials such as fluorite and perovskite oxides. Our work challenges the conventional wisdom that deep delithiation is a necessary condition for oxygen loss in layered oxide electrodes and highlights the importance of calendar ageing for investigating oxygen stability.

Phase-Structure Modulated Self-Supporting Indium-Bismuth Alloy Films as Anodes for Advanced Magnesium Ion Batteries.

Alloy-type anodes used in magnesium ion batteries (MIBs) have garnered significant attention in light of their substantial theoretical specific capacities and possible matchability with conventional electrolytes. However, the major challenges for alloy-type anodes are the sluggish transport kinetics as well as severe volume variations during the discharge/charge processes. Herein, we present a strategy for phase-structure modulation to fabricate a self-supporting In-Bi film through straightforward magnetron sputtering. In comparison to the single-phase In and Bi electrodes, the biphase InBi/Bi electrode displays markedly enhanced rate and cycling performance, with the discharge capacities of 303.1/292.6 mAh g-1 after 550/500 cycles at 200/2000 mA g-1, respectively. The exceptional Mg storage capability of the sputtered InBi/Bi electrode could be ascribed to the favorable two-phase configuration and increased phase boundaries, effectively accommodating volume expansion and accelerating Mg2+ ion transport. More importantly, the (de)magnesiation mechanism of InBi/Bi for MIBs was elucidated through operando X-ray diffraction.

Stabilization Strategies of Lithium Metal Anode Toward Dendrite-Free Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are considered as a most promising rechargeable lithium metal batteries because of their high energy density and low cost. However, the Li-S batteries mainly suffer the capacity decay issue caused by the shutting effect of lithium polysulfides and the safety issues arising from the Li dendrites formation. This review outlines the current issues of Li-S batteries. Furthermore, we comprehensively summarized the challenges encountered by Li anode in Li-S batteries, such as the heterogeneous deposition of the Li anode, the unstable solid electrolyte interface (SEI) layer, and volume expansion. Moreover, research progresses in the stabilization strategies of Li anodes (physical approaches, optimization of electrolyte, surface protection layer, and design of current collector) is discussed in detail. Lastly, the remaining challenges and future research directions of Li metal anode stabilization in Li-S batteries are also present.

Point cloud upsampling network based on pyramid pooling and self-attention mechanism

For the problems of irregular point cloud data and non-unique input size, a point-cloud upsampling network (PPSA-PU) based on Pyramid Pooling and Self-Attention mechanism is proposed. Multi-scale features are first extracted from the input point cloud using dense map convolution with different expansion rates, and the pyramid pooling module and self-attention mechanism are added. By applying the same pooling operation to regions of different sizes and numbers, the network is made to accept inputs of arbitrary size. Self-attention is used to weight the features to establish global correlation and improve the feature extraction capability. The features are then extended by the Self-Attention NodeShuffle (SA-NS) module, which uses a graph convolution layer to fuse neighbour information and learn new point features from the latent space. Finally, the coordinate reconstruction module is used to generate a dense up-sampled point cloud. Using the existing dataset to train and test the network and compare it with the existing up-sampling network, the experimental results show that PPSA-PU is better in terms of evaluation metrics and performance, and has better generalisation and robustness.

Predicting initial microlayer thickness in nucleate boiling using Landau–Levich theory

A phenomenological model is proposed to estimate the initial thickness of the liquid microlayer forming beneath a vapour bubble growing on a solid surface upon nucleate boiling. The model employs an analogy between the microlayer formation and the classic plate withdrawal problem. It calculates the microlayer thickness by considering it as a Landau–Levich film, where the thickness is a function of the meniscus speed and radius of curvature. Given the nearly hemispherical shape of the bubble during the early growth stage when the microlayer is first deposited, we assume that the meniscus speed can be approximated by the bubble expansion rate, and estimate the meniscus curvature using the Rayleigh equations. Unlike previous theories that assume that the bubble radius growth is proportional to the square root of time, the proposed model does not rely on any specific law of growth for vapour bubbles. The model is validated for predicting the microlayer thickness in water and ethanol, showing good agreement with experimental measurements and empirical correlations. Subsequent analyses of the microlayer interface profile address inconsistent reports – some described a wedge-like shape, whereas others reported a slight outward curvature with decreasing thickness in the outer region. This discrepancy is attributed to a reduction in the expansion rate of the microlayer's outer edge, particularly when the bubble reaches its maximum width. Our model provides insights into microlayer dynamics, essential to boiling heat transfer, as the evaporative heat flux through the microlayer is very sensitive to its initial thickness.

Structural design and investigation of Ti3C2 MXene as a conductive interlayer for improving the lithium-storage performance of PSi@C anode material

Silicon stands out as an ideal anode material for the next generation of lithium-ion batteries (LIBs) due to its abundant sources, low lithiation/delithiation potential, and high specific capacity. However, its practical application is impeded by significant volume expansion, leading to electrode structure damage. In this study, the Porous silicon(PSi)@C/Ti3C2 MXene composite was developed by dispersing porous micro-silicon@carbon (PSi@C) particles into layered stackable Ti3C2 MXene sheets using ultrasonic and freeze drying. The Ti3C2 MXene interlayer played a crucial role in enhancing the conductive crosslinking network between PSi@C particles, and providing efficient channels for electron transport/ion diffusion. Additionally, the Ti3C2 MXene interlayer served as a buffer to accommodate the substantial volume changes in silicon during electrochemical cycling. Consequently, the PSi@C/Ti3C2 MXene composite electrode demonstrated rapid electron/ion conduction and maintained structural stability. Remarkably, the electrode exhibited outstanding long cycle stability with 952 mAh g-1 at 0.5 A g-1 after 200 cycles and excellent rate performance with 542 mAh g-1 at 2 A g-1.

Varieties and cooking conditions difference in quality of instant brown rice

Amylose content is an important indicator that determines the hardness and softness of rice, which depends on rice varieties. Three types of specialty colored rice in Vietnam were selected for research on instant rice production including DH6 brown rice (DH6), Huyet Rong rice (HR), and Cam Cai Lay rice (CL). Proximate compositions and antioxidant properties such as total anthocyanin and total phenolic content in three kinds of rice were analyzed and compared. In addition, the effect of varieties and ratios of rice and water on the cooking time, volume expansion, antioxidant compounds and sensory properties were observed. The results showed that varieties led to differences in the nutritional profile of rice. CL and HR have the highest anthocyanin content (54.9-56.5 mg/100 g). DH6 brown rice is considered as the low amylose rice, with the content of amylose about 4.6%. Besides, it was also found that using “Cam Cai Lay” rice could create products with good structure and high sensory value. The results also confirmed that the product is of good quality when using a ratio of rice: water 1:2 and a cooking time of 30 mins. Types of rice and cooking conditions remarkably affected the quality of instant rice, which could further optimize for the up-scale process.

Synthesis of Rod‐Like Sb2Se3@MWCNT as Conductive‐Additive Free Anode for Sodium‐Ion Batteries

AbstractAntimony selenide (Sb2Se3) is a promising electrode material for sodium‐ion batteries (SIBs) due to its high theoretical capacity. However, volume expansion during sodiation/desodiation and the low conductivity of Sb2Se3 reduce the electrochemical performance. Herein, we synthesized Sb2Se3 nanorods (NRs) and combined them with multi‐walled carbon nanotubes (MWCNTs) using one‐step composite process to address these issues. MWCNTs can accommodate volume expansion and provide high conductivity. The fabricated Sb2Se3 NRs@MWCNT electrode exhibits improved cycle performance and cyclic stability without additional conductive carbons. The Sb2Se3 NRs@MWCNT electrode showed an enhanced specific capacity of 440 mAhg−1 at a current density of 0.1 Ag−1, compared to 220 mAhg−1 for the Sb2Se3 NRs electrode. Additionally, it exhibited good stability at high current density. The in‐situ electrochemical impedance spectroscopy (EIS) and Galvanostatic intermittent titration technique (GITT) were used to estimate the electrochemical properties and kinetics of Sb2Se3 NRs@MWCNT. These results showed that Sb2Se3 NRs@MWCNT have the potential as a conductive‐free anode material in SIBs.

3D-Aligner: advanced computational tool for correcting image distortion in expansion microscopy

Expansion Microscopy (ExM) is an innovative and cost-effective super-resolution microscopy technique that has become popular in cell biology research. It achieves super-resolution by physically expanding specimens. Since its introduction, ExM has undergone continuous methodological developments to enhance its resolution and labeling capabilities. However, ExM imaging often encounters sample drift during image acquisition due to the physical movement of the expanded hydrogel, posing a significant challenge for accurate image reconstruction. Despite many proposed experimental solutions to mitigate sample drift, a universal solution has yet to be established. In response to this challenge, we developed 3D-Aligner, an advanced and user-friendly image analysis tool designed to computationally correct drift in ExM images for precise three-dimensional image reconstruction and downstream quantification. We demonstrate that 3D-Aligner effectively determines and corrects drift in ExM images with different expansion rates and various fluorescently labeled biological targets, showcasing its capabilities and robustness in drift correction. Additionally, we validate the precision of 3D-Aligner by comparing drift values across different labeled targets and highlight the importance of drift correction in quantification of biological structures.

Defect-Mediated Formation of Oriented Phase Domains in a Lithium-Ion Insertion Electrode.

The performance and robustness of electrodes are closely related to transformation-induced nanoscale structural heterogeneity during (de)lithiation. As a result, it is critical to understand at atomic scale the origin of such structural heterogeneity and ultimately control the transformation microstructure, which remains a formidable task. Here, by performing in situ studies on a model intercalation electrode material, anatase TiO2, we reveal that defects─both preexisting and as-formed during lithiation─can mediate the local anisotropic volume expansion direction, resulting in the formation of multiple differently oriented phase domains and eventually a network structure within the lithiated matrix. Our results indicate that such a mechanism operated by defects, if properly harnessed, could not only improve lithium transport kinetics but also facilitate strain accommodation and mitigate chemomechanical degradation. These findings provide insights into the connection of defects to the robustness and rate performance of electrodes, which help guide the development of advanced lithium-ion batteries via defect engineering.

A hierarchical host microstructure enables regulated inner Li deposition for stable Li metal electrodes

Dendritic lithium (Li) deposition is a critical issue hindering the development of next-generation high-energy-density Li metal batteries (LMBs). Confining Li deposition within a three-dimensional host is a general strategy to suppress the volume expansion of the Li electrode. However, precise control of continuous Li growth in the pore space of the host is rarely investigated, which is a crucial issue to enable a high utilization ratio of the hosted Li for practical LMBs. Herein, a novel hierarchical host structure possessing a multifunctional secondary porous structure to regulate the continuous Li growth with high uniformity and reversibility is proposed. The secondary porous structure consisting of carbon nanotubes, nickel and Li2O-enriched solid electrolyte interphase is in-situ generated via lithiation reaction of a modified nickel foam scaffold, exhibiting high lithiophilicity, fast Li+ transportation and charge transfer. The LMB utilizing Li metal electrodes hosted by this rational structure achieved a stable cycling over 300 cycles with a practical LiFePO4 positive electrode (~2.5 mAh cm-2) at 0.5C/0.5C in the voltage window of 2.5-4.4 V. This work provides a novel approach to designing the host microstructure for constructing more stable Li metal electrode in practical LMBs.

ZnO Nanoparticle Assisted Liquid Metal for Dendrite-Free Zn Metal Anodes.

Dendrite growth and interfacial side reactions on Zn anode seriously affect the safety and service life of Zn ions batteries. Interface engineering is an effective way to solve these problems. Here, a liquid metal-ZnO composite coating with high ionic conductivity is creatively designed, which not only reduces the Zn2+ diffusion barrier but also increases the hydrogen evolution overpotential, thereby eliminating dendrite growth behavior and corrosion on the modified Zn anode. Moreover, its unique structure induces Zn deposition into the inner of coating, which can effectively avoid the volume expansion in the deposit layer of Zn anode. Therefore, it can cycle for 3000 h at an ultra-small polarization of 28 mV at 1 mA cm-2, and the microbattery assembled in combination with the MnO2 cathode also maintains 2000 cycles with high Coulomb efficiency, providing a general idea for the development of the next generation of rechargeable metal batteries.

Nano Silicon Integrated Hard Carbon from Conjugated Microporous Polymer for High‐Efficient Lithium Storage

AbstractIt is a significant issue to develop silicon/carbon composite anode with high‐capacity and long cycling stability for lithium‐ion batteries. However, the huge volume expansion of silicon during lithiation leads to severe pulverization of silicon, resulting in serious capacity fading over cycles. Herein, nano silicon integrated hard carbon (20Si@HC, 20 wt% nano silicon) is prepared by pyrolyzing nano silicon in‐situ coated a conjugated microporous polymer (CMP). CMP‐derived hard carbon coating features developed porous structure, which not only deliver a high lithium storage capacity, but also provide enough space for the volume expansion of nano silicon. When evaluated as an anode for lithium‐ion batteries, the 20Si@HC delivers an impressive 1037 mAh g−1 at 0.1 A g−1 and a capacity retention ratio of 72.07% for 100 cycles at 0.6 A g−1, providing some reference for designing high‐capacity silicon/carbon composites.

A single-cell 3D dynamic volume control system for chondrocytes.

In articular cartilage, zone-specific cellular morphology is a typical characteristic of cartilage tissue, which is related with chondrocyte function, inflammation and osteoarthritis (OA). Chondrocyte hypertrophic phenotype is a criticle physiological process which indicates a hallmark of chondrocyte terminal differentiation and bone formation. Thus, developing a in vitro cell culture system for dynamic regulation of single chondrocyte volume at a three-dimensional (3D) level is particularly necessary for understanding how physical cues of matrix microenvironment regulate chondrocyte fate and the degeneration of articular cartilage. Here, based on the soft lithography techniques, we have constructed well-defined single-cell 3D dynamic volume control system to recapitulate the physiological matrix microenvironment of single chondrocyte niche. The results of finite element analysis indicated that the stress and strain distribution in the cell culture region is homogeneous during the stretching process. Additionally, 3D dynamic volume expansion and compression of single cells in physiological or hyperphysiological can be realized in this cell culture system. Our device for single-cell 3D dynamic culture provides a microphysiological culture system for chondrocytes to explore the mechanisms of cartilage hypertrophy, as well as develops a new paradigm for functional cartilage tissue engineering and regenerative medicine.

Experimental investigation of the influence of drainage condition on change in saturation of sheared sand

This paper investigates the validity of the interpretation of results from testing saturated axisymmetric triaxial compression (ATC) sand specimens utilizing 3D synchrotron micro-computed tomography (SMT) to probe localized events that are completely missed or misinterpreted when analyzing ATC measurements based on global standard measurements. Drained and undrained experiments were conducted at low and high back pressures (BPs) coupled with multiple in situ 3D-SMT to acquire high-resolution scans of the specimens at different axial strains. Specimens tested under low BP exhibited a large pore air volume change, which was not detected by the pump system that represents standard volume measurement. The increase in air volume caused a significant reduction in the degree of saturation leading to a possible transition from saturated to partially saturated constitutive behavior. Undrained experiments exhibited a significant volume change contrary to the assumption of negligible volumetric strain for saturated undrained experiments. Air bubbles within the shear band for drained and undrained low BP specimens showed opposite capillary pressure responses, increased for drained and decreased for undrained cases, due to the variation in the mechanism by which each of the two experiments predominantly counters the volume expansion within the shear band.

A 3D flexible conductive network skeleton by SWCNT-COOH and PVA-PAA enabling high performance for Si anode

Silicon anode undergoes dramatic volume expansion during charge and discharge, causing structural and interfacial instability that severely degrades battery cycling performance. Herein, we propose a three-dimensional (3D) flexible self-standing SiMP/SWCNT-COOH@PVA/PAA anode, in which carboxylation-modified single-walled carbon nanotubes (SWCNT-COOH) construct a highly conductive and flexible skeleton to provide rapid electron transport channels for micron silicon (SiMP), while polyacrylic acid-polyvinyl alcohol (PVA-PAA) cross-linking layer forms a high-strength polymer interface to strengthen the conductive skeleton and helps to maintain the structural integrity of SiMP. The resulting electrode exhibits ultra-high electrical conductance (12406 S m−1) and exceptional mechanical characteristic (tensile strength of 46.95 MPa). More importantly, it demonstrates extremely stable electrochemical properties, with an impressive maximum capacity of approximately 2868.5 mAh g−1 at 0.2C, while retaining an exceptional 96.49 % of capacity even after 100 cycles. A consistent capacity of 1000 mAh g−1 at 1C throughout 1000 cycles is also realized. Furthermore, a flexible full battery based on SiMP/SWCNT-COOH@PVA/PAA anode achieves a discharge capacity of 49.5 mAh g−1 following 100 cycles, and illuminates a LED strip normally under various bending conditions. These results are expected to open a new way towards enhanced performance silicon-based electrodes within flexible LIBs.

Moulding Test and Process Parameter Optimization of Biomass Seedling Pots for Cow Dung and Corn Stover

In order to determine the optimal moulding process parameters of biomass seedling pots prepared from fermented cow dung mixed with corn stover, the moulding pressure, baking time, and baking temperature of biomass seedling pots were taken as the influencing factors, and the expansion rate, durability rate, wet swelling rate (48 h), and resistance to damage were taken as the evaluation indexes, and the Box–Behnken design of the response surface method was used to analyze the significance of interactions among the different influencing factors in the moulding process of biomass seedling pots and to optimize the moulding process. The experiment was conducted in the Biomass Laboratory of Heilongjiang Bayi Agricultural University. The response surface method Box–Behnken design was used to analyze the significance of the interaction between different influencing factors in the biomass seedling pots moulding process and optimize the moulding process. The results showed that the optimum moulding process conditions obtained using the Box–Behnken design were the following: a moulding pressure of 520.393 kN, baking temperature of 202.870 °C, and baking time of 8.573 min. The model was validated by testing and a response value of 10.522% was obtained for expansion, 99.598% for durability rate, 11.145% for wet swelling (48 h), and 4503.545 N for resistance to damage. The experimental verification showed that the deviation of the actual value obtained under this condition from the predicted value is less than 5%, indicating that the model reproduces well and meets the experimental requirements. Based on the optimal moulding process conditions determined in this experiment, the total porosity, EC, and pH of the Biomass seedling pots were determined to be 67.32%, 1.63 mS/cm, and 6.7, respectively, which met the seedling requirements.

Spatial and Temporal Change Analysis of Urban Built-Up Area via Nighttime Lighting Data—A Case Study with Yunnan and Guizhou Provinces

As urbanization accelerates, characteristics of urban spatial expansion play a significant role in the future utilization of land resources, the protection of the ecological environment, and the coordinated development of population and land. In this study, Yunnan and Guizhou provinces were selected as the study area, and the 2013–2021 National Polar-Orbiting Partnership’s Visible Infrared Imaging Radiometer Suite (NPP-VIIRS) nighttime light (NTL) data were utilized for spatial and temporal change analysis of urban built-up areas. Firstly, the built-up areas in Yunnan and Guizhou provinces were extracted through ENUI (Enhanced Nighttime Lighting Urban Index) indices, and then the urban expansion speed and urban center of gravity migration were constructed and used to explore and analyze the spatial and temporal change and expansion characteristics of built-up areas in Yunnan and Guizhou provinces. The results showed the following. (1) Due to the complementarity between data types, such as NTL, EVI, NDBI, and NDWI, ENUI has better performance in expressing urban characteristics. (2) Influenced by national and local policies, such as “One Belt, One Road”, transportation infrastructure construction, geographic location, the historical background, and other factors, the urban expansion rate of Yunnan and Guizhou provinces in general showed a continuous advancement from 2013 to 2021, and there were three years in which the expansion rate was positive. (3) The center of gravity migration distance of most cities in Guizhou Province shows a trend of increasing and then decreasing, while the center of gravity migration distance in Yunnan Province shows a trend of continuous decrease in general. From the perspective of migration direction, Guizhou Province has the largest number of migrations to the northeast, while Yunnan Province has the largest number of migrations to the southeast. (4) Influenced by policy, economy, population, geography, and other factors, urban compactness in Yunnan and Guizhou provinces continued to grow from 2013 to 2021. The results of this study can help us better understand urbanization in western China, reveal the urban expansion patterns and spatial characteristics of Yunnan and Guizhou provinces, and provide valuable references for development planning and policymaking in Yunnan and Guizhou provinces.