Solid-state Li-ion batteries employing a metallic lithium anode in conjunction with an inorganic solid electrolyte (ISE) are expected to offer superior energy density and cycle life. The realization of these metrics critically hinges on the simultaneous optimization of the ISE and the two electrode/electrolyte interfaces. In this Opinion article, we provide an overview of the materials and interfacial challenges that limit the performance of solid-state lithium metal batteries (SSLMBs). Owing to the importance of the Li/ISE interface, we dedicate a large section of this article to discuss the mechanistic aspects of lithium deposition at the Li/ISE interface. We further discuss a few recently proposed mechanisms that rationalize the growth of lithium through ISEs. We conclude our review with a brief discussion on the anode-free approach for fabricating SSLMBs where metallic lithium is generated in-situ from pre-lithiated cathodes.

Rapid industrial and urban development jointly with rising global population strongly affect the large-scale issues with drinking, groundwater, and surface water pollution. Concerns are not limited to environmental issues but also human health impact becoming serious global aspect. Organic pollution becomes a primarily serious hazard, therefore, the novel sophisticated approaches to treat them are thoroughly investigated. Among numerous materials, functionalized nanodiamonds are specific versatile nanocarbon material attracted ample attention thanks to their exceptional chemical, optical and electronic properties beneficial in the decomposition of harmful organic chemicals.This work delivers a comprehensive review of progress and perspectives on the green-friendly nanodiamonds, which are suitable for the degradation of emerging organic pollutants using numerous approaches utilizing them as an electro-oxidation catalyst; photocatalyst; oxidation agent, or adsorbing surface. Novel modification strategies of nanodiamonds (i.e., persulfates, oxides, or metals) remarkably improve pollutant removal efficiency and facilitate charge transfer and surface regeneration. Furthermore, we evaluated also the influence of various factors like pH, natural organic matters, or radical scavengers on the removal efficiency combining them with nanodiamond properties. The identified missing research gaps and development perspectives of nanodiamond surfaces in water remediation relating to other nanocarbon and metal catalysts were also here described.

All-solid-state batteries are an exciting technology for increased safety and energy density compared to traditional lithium-ion cells. Recently, we developed a theory of mapping inner potentials and thermodynamic driving forces specific to the solid-state batteries, allowing prediction of the “intrinsic” interfacial lithium barriers. This potential mapping methodology, based purely on calculated bulk and surface properties, enables fast screening of a variety of advanced solid electrolyte materials as well as a selection of cutting-edge high-voltage cathode materials, predicting properties of 48 distinct battery configurations. A number of cathode/electrolyte pairs are identified which have low “intrinsic” barriers to both the charge and discharge process at all states of charge, suggesting that they will most benefit from engineering efforts to reduce extrinsic interfacial impedance. These predictions agree well with available experimental measurements, which form only a subset of the predicted interfaces. Thus, this interface potential model will accelerate the design process from emerging materials to all-solid-state battery devices.

Hydrogen peroxide (H2O2) is a clean oxidizing reagent with many industrial, environmental, medical, and domestic applications. It has been frequently produced using the anthraquinone oxidation process. However, more recently, the electrochemical production of H2O2 has become a popular alternative, as this process is chemically green and sustainable since it employs abundant and inexpensive starting molecules (O2 and H2O). This review focuses on the electrochemical synthesis of H2O2 using the two-electron water oxidation reaction (2e− WOR) and two-electron oxygen reduction reaction (2e− ORR), both on boron-doped diamond (BDD) electrodes functioning as an anode or cathode, respectively. This review begins by identifying the important and fundamental characteristics of BDD electrodes, as well as the influence of their chemical and physical properties in the electrochemical production of H2O2. The principles and mechanism of the 2e− WOR and 2e− ORR are also discussed. In addition, various environmental applications of H2O2 electrochemical production (via the 2e− ORR and 2e− WOR) are addressed. Finally, the sustainability and costs of BDD electrodes and future strategies to improve BDD performance are considered.

The use of lithium metal as the negative electrode holds great promise for high energy density solid-state batteries (SSBs) of the future, but at the same time presents major technical challenges in their development. Li metal, with its high reactivity, soft and ductile nature, and propensity towards mechanical deformation during electrochemical cycling, is susceptible to the formation of various defects such as voids, cracks and filamentary deposits at the Li metal - solid electrolyte interface, that eventually cause rapid degradation of electrochemical cell performance. In order to gain insights into these interfacial processes and identify mechanisms for failure, in situ and operando characterisation approaches are essential. In this perspective, we present our opinions on the current state of such techniques, while highlighting the existing limitations and scope of these methods. We also endeavour to present opportunities for future research into developing and building on existing approaches to better evaluate the Li metal-solid electrolyte interface so as to guide the appropriate choice of materials to further enable efficient SSB architectures.

Mucus is an essential barrier material that separates organisms from the outside world. This slippery material regulates the transport of nutrients, drugs, gases, and pathogens toward the cell surface. The surface of the cell itself is coated in a mucus-like barrier of glycoproteins and glycolipids. Mucin glycoproteins are the primary component of mucus and the epithelial glycocalyx. Aberrant mucin production is implicated in diverse disease states from cancer and inflammation to pre-term birth and infection. Biological mucins are inherently heterogenous in structure, which has challenged understanding their molecular functions as a barrier and as biochemically active proteins. Therefore, many synthetic materials have been developed as artificial mucins with precisely tunable structures. This review highlights advances in design and synthesis of artificial mucins and their application in biomedical studies of mucin chemistry, biology, and physics.

High-entropy alloys (HEAs) and some complex alloys exhibit desirable properties and significant structural stability in harsh environments, including possible applications in advanced reactors. Energetic ion irradiation is often used as a surrogate for neutron irradiation; however, the impact of ion electronic energy deposition and dissipation is often neglected. Moreover, differences in recoil energy spectrum and density of cascade events on damage evolution must also be considered. In many chemically complex alloys, the mean free path of electrons is reduced significantly, thus their decreased thermal conductivity and slow dissipation of localized radiation energy can have noticeable effects on displacement cascade evolution that is greatly different from metals with high thermal conductivity. In this work, nanocrystalline HEAs of Ni20Fe20Co20Cr20Cu20 and nonequiatomic (NiFeCoCr)97Cu3, both having much lower room-temperature thermal conductivity than pure Ni or Fe, are chosen as model HEAs to reveal the role that electronic energy loss during ion irradiation has in complex alloys. The response of nanocrystalline HEAs is investigated under irradiation at room temperature using MeV Ni and Au ions that have different ratios of electronic energy to damage energy, which is the energy dissipated in displacing atoms. Different from previously reported amorphization of nanocrystalline SiC, experimental results on these HEAs show that, similar to the process in nanocrystalline oxide materials, both inelastic thermal spikes via electron–phonon coupling and elastic thermal spikes via collisions among atomic nuclei contribute to the overall grain growth. The growth follows a power law dependence with the total deposited ion energy, and the derived value of the power-exponent suggests that the irradiation-induced instability at and near grain boundaries leads to local rapid atomic rearrangements and consequently grain growth. The high power-exponent value can be attributed to the sluggish diffusion and delayed defect evolution arising from the chemical complexity intrinsic to HEAs. This work calls attention to quantified fundamental understanding of radiation damage processes beyond that of simplified displacement events, especially in simulating neutron environments.

Layered double hydroxides (LDHs) are emerging catalyst materials with inner layer water molecules and higher anion exchange capacity. They have been extensively used as catalyst materials owing to their high specific surface area, environmental friendliness, lower cost, and non-toxicity. However, the lower surface area and leaching of metal ions from LDHs composites reduce the process efficiency of the catalyst. Modifying the LDHs materials with other materials can improve the surface properties of the composite and enhance the catalytic performance. Herein, this review aims to summarize the recent progress of nanostructured modified LDHs materials, their classification, synthesis, and a detailed discussion on their characterization techniques. Further, this study also discusses the application of nanostructured modified LDHs materials as catalysts in advanced oxidation process (AOPs) for various organic pollutants removal.

All-solid-state batteries (ASSBs) using inorganic solid electrolytes (SEs) are in the spotlight for next-generation energy storage devices because of their potential for outstanding safety and high energy density. Recent progress in this field has been primarily based on advances in materials, such as the discovery of SEs with high ionic conductivities and the improvement of interfacial stability in electrodes. However, the use of inelastic SEs causes severe electrochemo-mechanical failures, such as cathode active material (CAM) disintegration, CAM/SE contact loss, and stress build-up during cycling, deteriorating the Li+ and e− transport pathways. Although these concerns have been addressed previously, they have not been contextualized systematically in terms of the mechanical interactions among the components and their impacts on electrochemical performance. Here, we categorize the electrochemo-mechanical effect in ASSBs and its ramifications in terms of stress sources, active materials, composite electrodes, and cell stacks.

This review summarizes recent advances in wastewater treatment using BDD anodes, involving different aspects of the chemical nature of the anode that are important during the oxidation of organic compounds in water. Synthesis parameters such as the proportion of diamond (sp3) and graphite (sp2), boron doping level, substrate nature and BDD surface modifications are discussed in this work. The influence of the salts dissolved in water, such as sulphate, carbonate, phosphate and chloride, during the treatment was also described. In addition, a new cycle for the oxidation of pollutants using BDD is included.

Swarming is a collective bacterial behavior in which a dense population of bacterial cells moves over a porous surface, resulting in the expansion of the population. This collective behavior can guide bacteria away from potential stressors such as antibiotics and bacterial viruses. However, the mechanisms responsible for the organization of swarms are not understood. Here, we briefly review models that are based on bacterial sensing and fluid mechanics that are proposed to guide swarming in the pathogenic bacterium Pseudomonas aeruginosa. To provide further insight into the role of fluid mechanics in P. aeruginosa swarms, we track the movement of tendrils and the flow of surfactant using a novel technique that we have developed, Imaging of Reflected Illuminated Structures (IRIS). Our measurements show that tendrils and surfactants form distinct layers that grow in lockstep with each other. The results raise new questions about existing swarming models and the possibility that the flow of surfactants impacts tendril development. These findings emphasize that swarm organization involves an interplay between biological processes and fluid mechanics.

Liquid crystalline elastomers (LCEs) have demonstrated tremendous potential in applications such as soft robotics, biomedical materials, electronics, sensors, and biomimetic systems. The physical properties of LCEs are controlled by the degree of crosslinking, nature of the mesogens, and mesogen orientation in the LCE network structure. A wide range of dynamic covalent bonds (DCBs) capable of dynamic bond exchange reactions (DBERs) have been introduced into LCE structures to obtain intelligent materials in recent decades. In this review article, we discuss the molecular constitution, macrostructure, morphing mechanism, recent advances in LCEs with dynamic covalent bonds, the influence of DCBs on self-healing, reprogramming and reprocessing properties of LCE actuators, and challenges and opportunities in incorporating dynamic chemistry in the field of LCE actuators.

The recent realization of twisted, two-dimensional, bilayers exhibiting strongly correlated states has created a platform in which the relation between the properties of the electronic bands and the nature of the correlated states can be studied in unprecedented ways. The reason is that these systems allow extraordinary control of the electronic bands’ properties, for example by varying the relative twist angle between the layers forming the system. In particular, in twisted bilayers the low energy bands can be tuned to be very flat and with a nontrivial quantum metric. This allows the quantitative and experimental exploration of the relation between the metric of Bloch quantum states and the properties of correlated states. In this work we first review the general connection between quantum metric and the properties of correlated states that break a continuous symmetry. We then discuss the specific case when the correlated state is a superfluid and show how the quantum metric is related to its superfluid stiffness. To exemplify such relation we show results for the case of superconductivity in magic angle twisted bilayer graphene. We conclude by discussing possible research directions to further elucidate the connection between quantum metric and correlated states’ properties.

The rapid growth of additive manufacturing (AM) technologies has enabled the emergence of geometrically sophisticated materials or structures with tailored and/or enhanced mechanical responses. In addition to dense-walled lattice structures, innovation within the past decade has identified that hollow-walled lattice topologies exhibit the multifaceted potential of competitive strength and rigidity, whilst displaying unique deformation behaviours, indicating that they may be an important subsequent step in lattice evolution. Hollow-walled sections facilitate density and geometrical parameters well below what is achievable by dense-walled sections, providing additional hierarchies of architecture at micrometre to even nanoscale proportion. Their wall thickness can range from 20 nm to 800 µm while the relative density can span three orders of magnitude between 0.01% and 30%. Despite nearly a decade of research into hollow-walled lattice topologies, no meta-analysis exists to provide an informative overview of these structures. This research addresses this deficiency and provides a data-driven review of hollow-walled lattice materials. It elucidates how these hollow-walled lattices deviate from the current limitations of dense-walled lattices and the underlying mechanisms that dictate their performance, with data accumulated from an exhaustive collection of literature sources. A range of new insights into their design and manufacture is discussed for their future research and applications in different engineering fields.

The Gibson-Ashby (G-A) model has been instrumental in the design of additively manufactured (AM-ed) metal lattice materials or mechanical metamaterials. The first part of this work reviews the proposition and formulation of the G-A model and emphasizes that the G-A model is only applicable to low-density lattice materials with strut length-to-diameter ratios greater than 5. The second part evaluates the applicability of the G-A model to AM-ed metal lattice materials and reveals the fundamental disconnections between them. The third part assesses the deformation mechanisms of AM-ed metal lattices in relation to their strut length-to-diameter ratios and identifies that AM-ed metal lattices deform by concurrent bending, stretching, and shear, rather than just stretching or bending considered by the G-A model. Consequently, mechanical property models coupling stretching, bending and shear deformation mechanisms are developed for various lattice materials, which show high congruence with experimental data. The last part discusses new insights obtained from these remedies into the design of strong and stiff metal lattices. In particular, we recommend that the use of inclined struts be avoided.

Cellulose nanocrystals are natural nanomaterials with a high aspect ratio, high specific area, excellent stability, and favorable optical performances. Cellulose nanocrystals can form cholesteric liquid crystals through a left-handed spiral arrangement. The suspension liquid of cellulose nanocrystals can retain the chiral cholesteric structure in the solid film after being completely dried, leading to the appearance of Bragg reflection and bright structural color in the visible spectrum. By changing the conditions or mixing with polymers, the cellulose nanocrystals film will show different structural colors due to the change of pitch. The film can cover almost the entire visible spectrum, which can be applied to various aspects such as sensing, anti-counterfeiting, detection, and so on. In this review, we elaborated on the synthesis and properties of cellulose nanocrystals materials and introduced the mechanism of structural color formation, as well as the current research progress and applications. Cellulose nanocrystals have become a hot spot in the field of structural color, and provide more research value for providing a cheap, easy-to-obtain, green-friendly, and high-biocompatibility natural photonic material.

Silicon carbide ceramics have many outstanding properties like high hardness, high thermal conductivity, high strength, low density, good electrical conductivity, good chemical resistance, and excellent wear resistance. Because of their valuable properties, SiC ceramics are helpful in various tribological applications. In this paper, the features and developments of tribology of SiC ceramics under lubrication are reviewed. The relevant strategies to enhance the tribological performance of SiC ceramics under lubrication, including microstructures, mechanical properties, surface characteristics, external factors, and secondary phases, are comprehensively discussed. The tribochemical reactions and Stribeck curves of SiC ceramics are also presented. Finally, future research directions of SiC ceramics in the field of tribology under lubrication are proposed. This paper aims to offer some theoretical basis for the design of low-friction and low-wear SiC ceramics under lubrication in the future and a better understanding of SiC ceramics used as various tribological components under lubrication.

Nuclear materials are often demanded to function for extended time in extreme environments, including high radiation fluxes with associated transmutations, high temperature and temperature gradients, mechanical stresses, and corrosive coolants. They also have a wide range of microstructural and chemical makeups, resulting in multifaceted and often out-of-equilibrium interactions. Machine learning (ML) is increasingly being used to tackle these complex time-dependent interactions and aid researchers in developing models and making predictions, sometimes with better accuracy than traditional modeling that focuses on one or two parameters at a time. Conventional practices of acquiring new experimental data in nuclear materials research are often slow and expensive, limiting the opportunity for data-centric ML, but new methods are changing that paradigm. Here we review high-throughput computational and experimental data approaches, especially robotic experimentation and active learning that is based on Gaussian process and Bayesian optimization. We show ML examples in structural materials (e.g., reactor pressure vessel (RPV) alloys and radiation detecting scintillating materials) and highlight new techniques of high-throughput sample preparation and characterizations, and automated radiation/environmental exposures and real-time online diagnostics. This review suggests that ML models of material constitutive relations in plasticity, damage, and even electronic and optical responses to radiation are likely to become powerful tools as they develop. Finally, we speculate on how the recent trends of using natural language processing (NLP) to aid the collection and analysis of literature data, interpretable artificial intelligence (AI), and the use of streamlined scripting, database, workflow management, and cloud computing platforms that will soon make the utilization of ML techniques as commonplace as the spreadsheet curve-fitting practices of today.

Lithium metal is regarded as one of the most ideal anode materials for next-generation batteries, due to its high theoretical capacity of 3860 mAh g−1 and low redox potential (−3.04 V vs standard hydrogen electrode). However, practical applications of lithium anodes are impeded by the uncontrollable growth of lithium dendrite and continuous reactions between lithium and electrolyte during cycling processes. According to reports for decades, artificial solid electrolyte interface (SEI), electrolyte additives, and construction of three-dimensional (3D) structures are demonstrated essential strategies. Among numerous approaches, metals that can alloy with lithium have been employed to homogenize lithium deposition and accelerate Li ion transportation, which attract more and more attention. This review aims to summarize the lithium alloying applied in lithium anodes including the fabricating approaches of alloy-containing lithium anodes, and the action mechanism and challenges of fabricated lithium anodes. Based on summarizing the literature, shortcomings and challenges as well as the prospects are also analyzed, to impel further research of lithium anodes and lithium-based batteries.