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The commercialization of rechargeable Li metal batteries is hindered by dendrite growth and volumetric variation. Herein, we report a Li-rich dual-phase Li-Cu alloy with built-in 3D ...conductive skeleton to replace conventional planar Li anode. The Li-Cu alloy is simply prepared by fusion of Li and Cu metals at a relatively low-temperature of 500 °C, followed by a cooling process where phase-segregation leads to metallic Li phase distributed in the network of LiCux solid solution phase. Different from the common Li alloy, the electrochemical alloying reaction between Li and Cu metals is not observed. Therefore, the lithiophilic LiCux nanowires guides conformal plating of Li and the porous framework provides superior dimensional stability for the anode. This unique ferroconcrete-like structure of Li-Cu alloy enables dendrite-free Li plating for an expanded cycling lifetime. Constructing a new type of Li alloy with in situ formed electrochemically inactive framework is a promising and easily scaled-up strategy toward practical application of Li metal anodes.
The growth of lithium (Li) dendrites hinders the application of Li metal anodes in rechargeable Li batteries. Herein, a dual-phase alloy of Li-Ca is proposed to replace Li metal as an advanced anode, ...which is composed of a Li metal phase and a CaLi
2
alloy phase. The three dimensional (3D) CaLi
2
alloy framework forms regular patterns
via
phase segregation while cooling down the molten Li-Ca alloy in a facile one-step fusion fabrication process, where pattern shape and mechanical stability change with the atomic ratio of Ca to Li. The porous CaLi
2
alloy framework is functionalized as a lithiophilic current collector in the lithiation process, featuring enhanced structural stability and suppressed Li dendrite growth. Consequently, the electrochemical performance of a dual-phase Li-Ca alloy anode with microsized patterns is significantly improved with a Li metal phase as the reservoir providing reversible capacity. This dual-phase Li alloy with a regularly arranged 3D lithiophilic framework provides a new solution for lithium metal batteries.
A dual-phase alloy with regular patterns as an advanced Li anode is prepared by a facile one-step fusion method for effectively suppressing Li dendrite growth and mitigating volume variation.
The lightweight spinel-corundum refractory was prepared using the Kirkendall effect when spherical particles Al2O3@CaCO3 were introduced into the ingredient. The mechanism of pore formation through ...in-situ pore formation combined with the Kirkendall effect to reduce the bulk density of the refractory to the lightweight has been investigated in detail. The properties of the lightweight spinel-corundum refractory have also been studied. The results showed that the calcium at the center of the spherical particle spreads outwards and reacts with Al2O3 in the shell to form calcium hexaluminate (CA6). After which a portion of CA6 reacts with spinel in the matrix to manufacture a solid solution phase (CM2A8). At the same time, the hollow structure forms at the center of the spherical particle due to the buildup of the Kirkendall pore. With the additional amount of the Al2O3@CaCO3 spherical particles reaches 30%, the samples fired in 1650 °C for 3 h can gain high compressive strength (119.8 MPa), high refractoriness under load (>1700 °C), low bulk density (2.76 g cm−3) and low thermal conductivity (1.36 W·(m·K) −1).
The Cu collector is modified with Ag and Sn coatings through a simple and efficient substitution reaction. Ag demonstrates higher lithiophilicity compared to Sn, and the gradient modification of the ...Cu foam enables control over the deposition site of Li metal. This leads to improved space utilization and enhanced C-rate performance of the 3D scaffold.
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Metallic lithium (Li) is highly desirable for Li battery anodes due to its unique advantages. However, the growth of Li dendrites poses challenges for commercialization. To address this issue, researchers have proposed various three-dimensional (3D) current collectors. In this study, the selective modification of a 3D Cu foam scaffold with lithiophilic elements was explored to induce controlled Li deposition. The Cu foam was selectively modified with Ag and Sn to create uniform Cu foam (U-Cu) and gradient lithiophilic Cu foam (G-Cu) structures. Density Functional Theory (DFT) calculations revealed that Ag exhibited a stronger binding energy with Li compared to Sn, indicating superior Li induction capabilities. Electrochemical testing demonstrated that the half cell with the G-Cu@Ag electrode exhibited excellent cycling stability, maintaining 550 cycles with an average Coulombic efficiency (CE) of 97.35%. This performance surpassed that of both Cu foam and G-Cu@Sn. The gradient modification of the current collectors improved the utilization of the 3D scaffold and prevented Li accumulation at the top of the scaffold. Overall, the selective modification of the 3D Cu foam scaffold with lithiophilic elements, particularly Ag, offers promising prospects for mitigating Li dendrite growth and enhancing the performance of Li batteries.
The corrosion resistance of lightweight and dense mullite–corundum refractories to cement materials was examined. The specimens following static crucible treatment were investigated using phase ...analysis, microstructure, and thermodynamic simulation. The results reveal that diffusion of the silica‐rich phase enhances alumina saturation solubility in the slag, reducing the corrosion resistance of the mullite–corundum refractories. The large proportion of closed pores and the continuous net‐like structure of anorthite created by the corrosion reaction in the matrix, on the other hand, prevent further slag penetration into the lightweight mullite–corundum refractories. As a result, the presence of the silica‐rich phase assures better slag penetration resistance of lightweight mullite–corundum refractories.
Lithium metal is an ideal anode material for lithium battery thanks to its ultra-high specific capacity and lowest redox potential. However, uncontrollable growth of lithium dendrites hinders its ...application due to local aggregation of lithium ions and anisotropic growth of lithium metal driven by uneven electric field distribution. Here a strategy is proposed to address this issue via utilizing porous equipotential body decorated with heterogeneous nucleation sites as advanced three-dimensional current collector. The conductive network of carbon nanofibers is recognized as a porous equipotential body, where the interior electric filed is zero due to the well-defined electric field shielding effect. In addition, copper nanoparticles as heterogeneous nucleation sites are uniformly anchored on carbon nanofibers, which guide lithium deposition evenly. As a result, lower impedance and higher Coulombic efficiency (∼97%) are achieved in modified lithium-copper cell. In particular, the cycling lifetime of modified symmetric lithium-lithium cell is expanded up to 500 cycles at extremely large current density of 50 mA cm−2.
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•Compression failure modes of multidirectional CFRP laminates with different dimensions were investigated experimentally.•Initial damage and crack propagation process of specimens ...with different thicknesses identified based on fractographic aspects.•Evaluation of compressive strength and failure mechanism based on cohesion finite element simulation.•Influence of the non-equal size effect on the compression failure process of CFRP is revealed from microscopic defects.
The composite strength refers to the ultimate local value rather than the average value of local strength, thus the effect of size effect needs to be considered. In this study, experimental and numerical approaches are used to evaluate the influence of size effect on the compressive characteristics and failure process of multidirectional carbon fiber reinforced composites. The representative failure modes of specimens with different thicknesses are described. The reasons for the difference in failure modes are analyzed by microstructure analysis, and the crack propagation process of specimens with different gauge lengths is identified. The simulation results and microscopic mechanism analysis reveal that with the increase of specimen thickness, the final failure mode develops from longitudinal cracking to multidirectional delamination, and finally evolves into shear failure through the thickness. Influenced by the free edge effect, the specimen thickness significantly affects the final failure mechanism by influencing the location of the initial cracking, and the size of the gauge section affects the site of matrix compression failure leading to a change in the final failure mode. These findings provide some helpful guidance for the design and fabrication of thick composite structures.
Abstract
To address the issues of node interaction power overrun and high carbon emissions that may arise during distributed optimization in multi‐energy parks (MEPs), this paper proposes a ...distributed low‐carbon and economic operation method for multi‐energy parks based on a cloud platform that considers network transmission capacity.The proposed method achieves maximun profit by designing a two layer collaborative architecture for distributed optimization operations. At the top level, cloud platform services are utilized to build a model for checking network transport capacity and carbon emission quotas, optimizing network node over‐limit inspection . The bottom layer constructs a distributed optimization model for multi‐energy complementation in each park, taking into account the information privacy and individual interests of each multi‐energy park. An improved alternating direction multiplier method (ADMM) is proposed to effectively solve the two‐layer framework. The case studies show that the distributed optimization method under cloud platform services proposed in this paper can achieve maximum revenue for integrated energy service provider while ensuring the safe operation of multi‐energy parks, and reasonably allocate the benefits of collaborative operation among various parks while promoting carbon emission reduction.
As one of the promising and extensively studied alloy semiconductors, the optoelectronic properties of Si1-xGex alloys have been well studied, but fundamental electromagnetic (EM) properties are ...rarely explored and discussed. In this work, the EM excitations of magnetic multipoles and toroidal dipoles in Si1-xGex based permittivity-asymmetric metasurface at near-infrared spectral region are investigated. Multiple Fano resonances (FRs) occur in the structure, and the formation mechanisms of resonance excitations are analyzed in detail combining theory with EM field distributions. In addition, the proposed metasurface is also investigated for its potential as a refractive index sensor due to its finer spectral property. It is hoped that our work will help to understand the EM properties of Si1-xGex alloys and find its potential applications in optics, such as refractive index sensing. The results obtained here provide fundamental insights into the exploration of EM excitations of Si1-xGex alloys.
Implantable technologies are becoming more widespread for biomedical applications that include physical identification, health diagnosis, monitoring, recording, and treatment of human physiological ...traits. However, energy harvesting and power generation beneath the human tissue are still a major challenge. In this regard, self‐powered implantable devices that scavenge energy from the human body are attractive for long‐term monitoring of human physiological traits. Thanks to advancements in material science and nanotechnology, energy harvesting techniques that rely on piezoelectricity, thermoelectricity, biofuel, and radio frequency power transfer are emerging. However, all these techniques suffer from limitations that include low power output, bulky size, or low efficiency. Photovoltaic (PV) energy conversion is one of the most promising candidates for implantable applications due to their higher‐power conversion efficiencies and small footprint. Herein, the latest implantable energy harvesting technologies are surveyed. A comparison between the different state‐of‐the‐art power harvesting methods is also provided. Finally, recommendations are provided regarding the feasibility of PV cells as an in vivo energy harvester, with an emphasis on skin penetration, fabrication, encapsulation, durability, biocompatibility, and power management.
This report describes the state‐of‐the‐art energy harvesting technologies for implantable devices with a comparison between different power harvesting methods. It offers recommendations regarding the feasibility of photovoltaic cells as an in vivo energy harvester, with an emphasis on skin penetration, fabrication, encapsulation, durability, biocompatibility, and power management.
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