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Covalent organic frameworks (COFs), as a novel class of functional polymers, exhibit versatile applications due to their crystalline porous structures and conjugated skeletons. However, synthesis of COFs with high crystallinity still faces great challenges, especially for scale-up preparation. Herein we report a two-step solvothermal process to improve crystallinity of COFs. The first step focuses on polycondensation of monomers with no need for optimizing crystallization conditions. In the second step, appropriate solvothermal conditions are used to facilitate crystallization of the COFs through defects correction and structural repairing. Furthermore, this strategy could also be applicable to scale-up synthesis of high quality COFs, which lays a foundation for their practical applications.

Lithium plating in working batteries has attracted wide attention in the exploration of safe energy storage. Establishing an effective and rapid early-warning method is strongly considered but quite challenging since lithium plating behavior is determined by diverse factors. In this contribution, we present a non-destructive electrochemical detection method based on transient state analysis and three-electrode cell configuration. Through dividing the iR drop value by the current density, the as-obtained impedance quantity (Ri) can serve as a descriptor to describe the change of electrochemical reaction impedance on the graphite anode. The onset of lithium plating can be identified from the sharp drop of Ri. Once the dendritic plated lithium occurs, the extra electrochemical reactions at the lithium interfaces leads to growing active area and reduced surface resistance of the anode. We proposed a protocol to operate the batteries under the limited capacity, which renders the cell with 98.2% capacity retention after 1000 cycles without lithium plating. The early-warning method has also been validated in in-situ optical microscopy batteries and practical pouch cells, providing a general but effective method for online lithium plating detection towards safe batteries.

Lithium–sulfur (Li–S) batteries are highly regarded as next-generation energy storage devices due to their ultrahigh theoretical energy density of 2600 Wh kg−1. However, practical high-energy-density Li–S pouch cells suffer from limited cycling lifespan with rapid loss of active materials. Herein, systematic evaluation on a 400 Wh kg−1 Li–S pouch cell is carried out to reveal the working and failure mechanism of Li–S batteries under practical conditions. Electrode morphology, spatial distribution and species analysis of sulfur, and capacity retention of electrodes are respectively evaluated after the first cycle of discharge or charge. Considerable lithium polysulfides are found in electrolyte even at the end of discharge or charge, where the sulfur redox reactions are reversible with high capacity retention. Meanwhile, severe morphology change is identified on lithium metal anode, yet there remains substantial active lithium to support the following cycles. This work not only demonstrates unique behaviors of Li–S batteries under practical conditions, which is essential for promoting the progress of Li–S pouch cells, but also affords a systematic evaluation methodology to guide further investigation on high-energy-density Li–S batteries.

The lithium (Li) metal anode is an integral component in an emerging high-energy-density rechargeable battery. A composite Li anode with a three-dimensional (3D) host exhibits unique advantages in suppressing Li dendrites and maintaining dimensional stability. However, the fundamental understanding and regulation of solid electrolyte interphase (SEI), which directly dictates the behavior of Li plating/stripping, are rarely researched in composite Li metal anodes. Herein, the interaction between a polar polymer host and solvent molecules was proposed as an emerging but effective strategy to enable a stable SEI and a uniform Li deposition in a working battery. Fluoroethylene carbonate molecules in electrolytes are enriched in the vicinity of a polar polyacrylonitrile (PAN) host due to a strong dipole–dipole interaction, resulting in a LiF-rich SEI on Li metal to improve the uniformity of Li deposition. A composite Li anode with a PAN host delivers 145 cycles compared with 90 cycles when a non-polar host is employed. Moreover, 60 cycles are demonstrated in a 1.0 Ah pouch cell without external pressure. This work provides a fresh guidance for designing practical composite Li anodes by unraveling the vital role of the synergy between a 3D host and solvent molecules for regulating a robust SEI.

In light of the increasing demand for environmental protection and energy conservation, the recovery of highly valuable metals, such as Li, Co, and Ni, from spent lithium-ion batteries (LIBs) has attracted widespread attention. Most conventional recycling strategies, however, suffer from a lack of lithium recycling, although they display high efficiency in the recovery of Co and Ni. In this work, we report an efficient extraction process of lithium from the spent LIBs by using a functional imidazolium ionic liquid. The extraction efficiency can be reached to 92.5% after a three-stage extraction, while the extraction efficiency of Ni-Co-Mn is less than 4.0%. The new process shows a high selectivity of lithium ion. FTIR spectroscopy and ultraviolet are utilized to characterize the variations in the functional groups during extraction to reveal that the possible extraction mechanism is cation exchange. The results of this work provide an effective and sustainable strategy of lithium recycling from spent LIBs.

SiC ceramics were fabricated by SPS sintering at 1850 ℃ with different amounts of Ti3AlC2. The effects of Ti3AlC2 content on the microstructure and electrical properties of the material were discussed. The densification and electrical properties of SiC ceramics have been improved by adding MAX phase Ti3AlC2. Ti3AlC2 decomposes to produce TiC and Al in the sintering process. The conductivity of SiC ceramics is elevated by TiC serving as a conductive second phase, and Al is dissolved into SiC lattice to promote the densification of SiC ceramics. With the addition of 15 wt% Ti3AlC2, the voltage-current curve of the sample changes from nonlinear to linear electrical characteristics with the resistivity dropping to 52 Ω cm. Moreover, the introduction of Ti3AlC2 reduces the temperature sensitivity of SiC ceramics. When the Ti3AlC2 content reaches 15 wt%, the resistivity of SiC ceramics remains relatively constant within the range of 20–400 ℃.

Cemented carbide has huge applications in industrial production, but its high mechanical properties also increase the difficulty of processing. In this work, ultrasonic vibration-assisted grinding technology is used for the precision manufacturing of cemented carbide. The influence of the dynamic trajectory of the grains on the material removal process is analyzed. The morphology and roughness of the processed surface are measured and studied. It was observed that in the conventional grinding, the blade pattern is obvious with some defects on the surface. While in the ultrasonic vibration-assisted grinding, the material surface is mainly distributed with pits and small protrusions, and there is no obvious blade pattern. According to the roughness test, the roughness of ultrasonic vibration-assisted grinding is better than that of conventional grinding, and the increase in amplitude has a significant effect on the improvement of roughness. When the amplitude increases from 3μm to 9μm, the surface roughness is improved about 38.1%. The research of ultrasonic vibration-assisted grinding should be of great importance for promote the high-efficiency and high-quality processing and special applications of cemented carbide.

Oxygen reduction reaction (ORR) constitutes the core process of many energy storage and conversion devices including metal–air batteries and fuel cells. However, the kinetics of ORR is very sluggish and thus high-performance ORR electrocatalysts are highly regarded. Despite recent progress on minimizing the ORR half-wave potential as the current evaluation indicator, in-depth quantitative kinetic analysis on overall ORR electrocatalytic performance remains insufficiently emphasized. In this paper, a quantitative kinetic analysis method is proposed to afford decoupled kinetic information from linear sweep voltammetry profiles on the basis of the Koutecky–Levich equation. Independent parameters regarding exchange current density, electron transfer number, and electrochemical active surface area can be respectively determined following the proposed method. This quantitative kinetic analysis method is expected to promote understanding of the electrocatalytic effect and point out further optimization direction for ORR electrocatalysis.

Lithium metal batteries (LMBs) are highly considered as promising candidates for next-generation energy storage systems. However, routine electrolytes cannot tolerate the high potential at cathodes and low potential at anodes simultaneously, leading to severe interfacial reactions. Herein, a highly concentrated electrolyte (HCE) region trapped in porous carbon coating layer is adopted to form a stable and highly conductive solid electrolyte interphase (SEI) on Li metal surface. The protected Li metal anode can potentially match the high-voltage cathode in ester electrolytes. Synergistically, this ingenious design promises high-voltage-resistant interfaces at cathodes and stable SEI with abundance of inorganic components at anodes simultaneously in high-voltage LMBs. The feasibility of this interface-regulation strategy is demonstrated in Li | LiFePO4 batteries, realizing a lifespan twice as long as the routine cells, with a huge capacity retention enhancement from 46.4% to 88.7% after 100 cycles. This contribution proof-of-concepts the emerging principles on the formation and regulation of stable electrode/electrolyte interfaces in the cathode and anode simultaneously towards the next-generation high-energy–density batteries.

The serious zinc dendrites and poor cyclability at high cathode loading owing to the strong solvation effect of traditional aqueous electrolytes are the main bottlenecks to the development of aqueous rechargeable zinc-ion batteries (ARZIBs). Here, we design an ether-water hybrid zinc-ion electrolyte with bifunctional roles of not only unplugging the dendrites bottleneck at the Zn anode but also extending the cycle life at high cathode loading. A cyclic ether (1,4-dioxane (DX)) is incorporated into traditional ZnSO4-based electrolytes to finely tune the solvation sheath of Zn2+. DX is found to guide the deposition orientation of zinc along the (002) plane, leading to not a dendritic structure but distinctively dense lamellar deposition due to the stronger affinity of the cyclic DX molecules toward Zn(002) than that of water, which is proven by density functional theory calculations. The cycling lifespan of the Zn anode extends up to over 600 h at 5.0 mA cm-2 and maintains extremely high Coulombic efficiency of 99.8%, thereby further enabling the Zn-MnO2 full cells to stably cycle at an ultrahigh mass loading of 9.4 mg cm-2, paving the way to their practical applications. This work also provides a novel electrolyte regulating solution for other aqueous multivalent metal-ion batteries.

A potassium-doped carbon nitride (K-CN) was prepared by a simple thermal polymerization method. The prepared K-CN was characterized by Fourier infrared spectroscopy (FT-IR), powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The obtained K-CN exhibited excellent catalytic activity for synthesis of 4H-chromene derivatives via one-pot three-component reaction of salicylaldehyde, cyclohexane-1,3-diones and 4-hydroxycoumarin in water/ethyl lactate at room temperature. The reported method shows significant advantages, such as high yield, mild and clean reaction conditions, the use of recyclable catalyst and ethyl lactate/water as an environmentally friendly solvent, multi-component reaction at room temperature, no chromatographic separation and suitable for large-scale synthesis.

A Au55 nanocluster with the composition of [Au55 (p-MBT)24 (Ph3 P)6 ](SbF6 )3 (p-MBT=4-methylbenzenethiolate) is synthesized via direct reduction of gold-phosphine and gold-thiolate precursors. Single-crystal X-ray diffraction reveals that this Au55 nanocluster features a face-centered cubic (fcc) Au55 kernel, different from the well-known two-shell cuboctahedral arrangement in Au55 (Ph3 P)12 Cl6 . The Au55 cluster shows a wide optical absorption band with optical energy gap (Eg =1.28 eV). It is found that the exclusion of chloride is crucial for the formation of the title cluster, otherwise rod-like [Au25 (SR)5 (PPh3 )10 Cl2 ]2+ is obtained. The strategy to run synthetic reaction in the absence of halide leads to new members of phosphine/thiolate co-protected metal nanoclusters. The Au55 nanocluster exhibits high catalytic activity and selectivity for electrochemical reduction of CO2 to CO; the Faradaic efficiency (FE) reaches 94.1 % at -0.6 V vs. reversible hydrogen electrode (RHE).

The challenges of improving electrical conductivities and enhanced rapid dynamics are active research areas in the modification of Prussian blue (PB) and Prussian blue analogues (PBAs), which are used as excellent cathodes of sodium-ion batteries (SIBs). Herein, the terephthalic acid etched stepwise hollow bulky PB cubes and the intimate contact mesoporous carbon (CMK-3) particles with the adhered minisize PB cubes can together build continuous conductive networks. The composite (donated as N-PB@CMK) has high electrical conductivity, low resistance, and ultrahigh specific surface, which can lead to high capacitive contribution ratios. The N-PB@CMK electrode can deliver a discharge capacity of 120 mAh g-1 and maintain retention of 85.0% after cycling for 200 cycles at a current density of 100 mA g-1. Even cycling at 1 A g-1, the reversible capacity can be measured to 102 mAh g-1 and exhibit stability over a long cycle. In situ Raman spectroscopy and X-ray diffraction (XRD) patterns were further measured to illustrate the phase transition of crystal structure along with the extraction/insertion processes of Na+ ions. Especially, the assembled full cell with NaTi2(PO4)3@C anode can also show good stability and provide promising insights of applying the N-PB@CMK for energy storage systems in the future.

Solid electrolyte interphase (SEI) has been widely recognized as the most important and the least understood component in lithium batteries. Considering the intrinsic instability in both chemical and mechanical, the failure of SEI is inevitable and strongly associated with the performance decay of practical working batteries. In this Review, the failure mechanisms and the corresponding regulation strategies of SEI are focused. Firstly, the fundamental properties of SEI, including the formation principles, and the typical composition and structures are briefly introduced. Moreover, the common SEI failure modes involving thermal failure, chemical failure, and mechanical failure are classified and discussed, respectively. Beyond that, the regulation strategies of SEI with respect to different failure modes are further concluded. Finally, the future endeavor in further disclosing the mysteries of SEI is prospected.

Lithium ion batteries have achieved extensive applications in portable electronics and recently in electronic vehicles since its commercialization in 1990s. The vast applications of lithium ion batteries are not only derived from the innovation in electrochemistry based on emerging energy materials and chemical engineering science, but also the technological advances in the powder technologies for electrode processing and cell fabrication. Revealing the effects of powder technology on electrode microstructure evolution during electrode processing is with critical value to realize the superior electrochemical performance. This review presents the progress in understanding the basic principles of the materials processing technologies for electrodes in lithium ion batteries. The impacts of slurry mixing and coating, electrode drying, and calendering on the electrode characteristics and electrochemical performance are comprehensively analyzed. Conclusion and outlook are drawn to shed fresh lights on the further development of efficient lithium ion batteries by advancing powder technologies and related advanced energy materials.

Precursor infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI) were used to fabricate SiC/SiC composites on a four-step 3D SiC fibre preform deposited with a pyrolytic carbon interface. The effects of fabrication processes on the microstructure and mechanical properties of the SiC/SiC composites were studied. Results showed the presence of irregular cracks in the matrix of the SiC/SiC composites prepared through PIP, and the crystal structure was amorphous. The room temperature flexural strength and modulus were 873.62 MPa and 98.16 GPa, respectively. The matrix of the SiC/SiC composites prepared through CVI was tightly bonded without cracks, the crystal structure had high crystallinity, and the room temperature bending strength and modulus were 790.79 MPa and 150.32 GPa, respectively. After heat treatment at 1300 °C for 50 h, the flexural strength and modulus retention rate of the SiC/SiC composites prepared through PIP were 50.01% and 61.87%, and those of the composites prepared through CVI were 99.24% and 96.18%, respectively. The mechanism of the evolution of the mechanical properties after heat treatment was examined, and the analysis revealed that it was caused by the different fabrication processes of the SiC matrix. After heat treatment, the SiC crystallites prepared through PIP greatly increased, and the SiOxCy in the matrix decomposed to produce volatile gases SiO and/or CO, ultimately leading to an increase in the number of cracks and porosity in the material and a decrease in the material load-bearing capacity. However, the size of the SiC crystallites prepared through CVI hardly changed, the SiC matrix was tightly bonded without cracks, and the load-bearing capacity only slightly changed.

The lithium-sulfur (Li-S) battery is regarded as a promising secondary battery. However, constant parasitic reactions between the Li anode and soluble polysulfide (PS) intermediates significantly deteriorate the working Li anode. The rational design to inhibit the parasitic reactions is plagued by the inability to understand and regulate the electrolyte structure of PSs. Herein, the electrolyte structure of PSs with anti-reductive solvent shells was unveiled by molecular dynamics simulations and nuclear magnetic resonance. The reduction resistance of the solvent shell is proven to be a key reason for the decreased reactivity of PSs towards Li. With isopropyl ether (DIPE) as a cosolvent, DIPE molecules tend to distribute in the outer solvent shell due to poor solvating power. Furthermore, DIPE is more stable than conventional ether solvents against Li metal. The reactivity of PSs is suppressed by encapsulating PSs into anti-reductive solvent shells. Consequently, the cycling performance of working Li-S batteries was significantly improved and a pouch cell of 300 Wh kg-1 was demonstrated. The fundamental understanding in this work provides an unprecedented ground to understand the electrolyte structure of PSs and the rational electrolyte design in Li-S batteries.

The first all-amidinate-protected gold nanocluster [Au28 (Ph-form)12 ](OTf)2 (Ph-form=N,N'-diphenylformamidinate) (Au28 ) has been synthesized and structurally resolved. Single crystal X-ray diffraction reveals that Au28 has a compact Au4 @Au24 tetrahedral core-shell structure of T symmetry, which is fully protected by 12 bridging formamidinate ligands. This cluster is quite robust as indicated by the fact that it can stay intact in solution at 80 °C for 6 d. It exhibits excellent catalytic performance for the electroreduction of CO2 with 96.5 % Faradaic efficiency (FE) at -0.57 V and a maximum TOF of 1731 h-1 at -0.87 V. Its superior stability is also manifested in the fact that the supported catalyst Au28 /CNTs maintains stable potentials at ca. -0.69 V for 40 h with FE(CO)s>91 %. A superatomic electron configuration of 1S2 1P6 2S2 1D4 has been clarified by DFT computations, and the strong gold-ligand binding and geometric shell closure account for the superior stability of Au28 .

Uncontrolled Li plating in graphite electrodes endangers battery life and safety, driving tremendous efforts aiming to eliminate Li plating. Herein we systematically investigate the boundary of Li plating in graphite electrode for safe lithium-ion batteries. The cell exhibits superior safety performance than that with Li dendrites by defining the endurable amount of uniform Li plating in graphite anode. The presence of "dead Li" can be eliminated owing to the uniform distribution of Li plating, and the average Coulombic efficiency for deposited Li during reversible plating/stripping process is decoupled as high as about 99.5 %. Attributing to the limited Li plating with superior Coulombic efficiency, the LiNi0.5 Mn0.3 Co0.2 O2 | graphite cell achieves a high capacity retention of 80.2 % over 500 cycles. This work sheds a different light on further improving the fast-charging capability, low-temperature performance, and energy density of practical lithium-ion batteries.

Lithium–sulfur (Li–S) battery is regarded as one of the most promising next-generation energy storage systems due to the ultra-high theoretical energy density of 2600 Wh kg−1. To address the insulation nature of sulfur, nanocarbon composition is essential to afford acceptable cycling capacity but inevitably sacrifices the actual energy density under working conditions. Therefore, rational structural design of the carbon/sulfur composite cathode is of great significance to realize satisfactory electrochemical performances with limited carbon content. Herein, the cathode carbon distribution is rationally regulated to construct high-sulfur-content and high-performance Li–S batteries. Concretely, a double-layer carbon (DLC) cathode is prepared by fabricating a surface carbon layer on the carbon/sulfur composite. The surface carbon layer not only provides more electrochemically active surfaces, but also blocks the polysulfide shuttle. Consequently, the DLC configuration with an increased sulfur content by nearly 10 wt% renders an initial areal capacity of 3.40 mAh cm−2 and capacity retention of 83.8% during 50 cycles, which is about two times than that of the low-sulfur-content cathode. The strategy of carbon distribution regulation affords an effective pathway to construct advanced high-sulfur-content cathodes for practical high-energy-density Li–S batteries.

The cycle-to-cycle variations (CCVs) in reciprocating internal combustion engines may cause negative influence on diving performance, fuel economy, and emissions. Especially, lean-burn technology or exhaust gas recirculation (EGR) was used to improve engine combustion efficiency and reduce NOx, and the combustion boundary was limited by increased CCVs. Therefore, it was important to identify the complex dynamics of CCVs and to take measures for inhibiting them. The CCVs based on indicated mean effective pressure (IMEP) time series were examined in a lean-burn natural gas engine with a non-uniform pre-mixture based on statistical and multifractal theories. Tests were conducted at an engine speed of 1000 rpm and low loads of 10% and 25%, and combustion data at an engine load of 10% were analysed in detail because the CCVs are less sensitive to changes of gas injection timing (GIT) at the higher engine load. The nonlinear dynamics of the CCVs was revealed at the different GIT from 1° to 120°CA ATDC. The statistical properties of IMEP time series were characterised by distributions of probability density functions (PDF), the multifractal complexities of the combustion fluctuations were quantitatively analysed by the singularity spectra in terms of the Holder exponent based on the theory of wavelet transform modulus maxima, and the primary source leading to the increased CCVs and complex dynamics in a natural gas engine with a non-uniform pre-mixture was identified using 3D-computational fluid dynamics simulations. Results show that as the GIT increased, the kurtosis of the IMEP time series systematically decreased from 592 to 1.8, the fast dynamics transitions from super-Gaussian to quasi-Gaussian distributions in combustion system were revealed, and the lower value of kurtosis implied the lower degree of intermittency. Except for the GIT of 60°CA ATDC, the value of the Holder exponent $$h_{0} > 0.5$$ , which implies that the CCVs for the other GITs behaved like a persistent walk or positive correlation. For GITs of 60° and 90°CA ATDC, the narrow broadness of the singularity spectrum implicated a monofractality, while the obvious multifractal properties could be identified for the other GITs. The transitions of the dynamic behaviours may be caused by the degree of mixture in-homogeneity combined with a new mechanism of “prior-cycle effects” proposed in this paper, and the effect mechanism was not only associated with the residual gas in the cylinder but also with the residual gas fuel in the intake port, rather than independent effect of residual gas in cylinder reported in previous researches. Our research results provided the deeper understanding on the dynamics of combustion system in multi-point injection natural gas engines and may be beneficial to achieve nonlinear prediction and to develop improved control strategies for inhibiting the CCVs.

The self-assembly of biomacromolecules is an extremely important process. It is potentially useful in the fields of life science and materials science. To carry out the study on the self-assembly of proteins, it is necessary to find out the suitable self-assembly conditions, which have always been a challenging task in practice. Inspired by the screening technique in the field of protein crystallization, we proposed using the same screening technique for seeking suitable protein self-assembly conditions. Based on this consideration, we selected 5 proteins (β-lactoglobulin, hemoglobin, pepsin, lysozyme, α-chymotrypsinogen (II) A) together with 5 screening kits (IndexTM, BML, Morpheus, JCSG, PEG/Ion ScreenTM) to investigate the performance of these crystallization screening techniques in order to discover new optimized conditions of protein self-assembly. The screens were all kept at 293 K for certain days, and were analyzed using optical microscope, scanning electron microscope, transmission electron microscope, atomic force microscope, fluorescence microscope, and atomic absorption spectroscope. The results demonstrated that the method of protein crystallization screening can be successfully applied in the screening of self-assembly conditions. This method is fast, high throughput, and easily implemented in an automated system, with a low protein consumption feature. These results suggested that such strategy can be applied to finding new conditions or forms in routine research of protein self-assembly. KEY POINTS: • Protein crystallization screening method is successfully applied in the screening of self-assembly conditions. • This screening method can be applied on various kinds of proteins and possess a feature of low protein consumption. • This screening method is fast, high throughput, and easily implemented in an automated system.

Solid electrolyte interphase (SEI) has been widely employed to describe the new phase formed between anode and electrolyte in working batteries. Significant advances have been achieved on the structure and composition of SEI as well as on the possible ion transport mechanism. However, the nucleation and growth mechanism of SEI catches little attention, which requires the establishment of isothermal electrochemical crystallization theory. Herein we explore the virgin territory of electrochemically crystallized SEI. By using potentiostatic method to regulate the decomposition of anions, an anion-derived SEI forms on graphite surface at atomic scale. After fitting the cur-rent-time transients with Laviron theory and Avrami formula, we conclude that the formation of anion-derived interface is surface reaction controlled and obeys the two-dimensional (2D) progressive nucleation and growth model. Atomic force microscope (AFM) images emphasize the conclusion, which reveals the mystery of isothermal electrochemical crystallization of SEI.

Metal-alloyed atomic catalysts such as single-atom alloys have attracted much attention due to their high atom economy and their unique catalytic properties. Recently, we found that a SiO2-supporte...

SiC-AlN ceramics were pressureless sintered at 2150 °C under N2 atmosphere, while B4C and C were added to promote the sintering process. The microstructure, electrical and mechanical properties of the as-sintered ceramics prepared by different AlN addition are discussed. More AlN addition tends to lead a smaller grain size. As AlN contents go up, the varistor voltage of the samples increases sharply from 17.304v·mm−1 to more than 100 v·mm−1 because of the improvement of grain boundary resistance. Correspondingly, the reasons for the increase of grain boundary resistance are: (1) the improvement of carrier compensation increases the Schottky barrier height and width; (2) more grain boundaries increase the number of Schottky barriers. In addition, the electrical properties of the same components sintered under N2 and Ar have been compared, that the varistor voltage of the same component SiC-AlN ceramics sintered under N2 are much higher than those under Ar (about 2 orders of magnitude). With the increase of AlN contents, the mechanical properties remain unchanged except the little reduction of Vickers hardness.

Lithium ion battery has achieved great success in portable electronics and even recently electronic vehicles since its commercialization in 1990s. However, lithium‐ion batteries are confronted with several issues in terms of the sustainable development such as the high price of raw materials and electronic products, the emerging safety accidents, etc. The recent progresses are herein emphasized on lithium batteries for energy storage to clearly understand the sustainable energy chemistry and emerging energy materials. The Perspective presents novel lithium‐ion batteries developed with the aims of enhancing the electrochemical performance and sustainability of energy storage systems. First, revolutionary material chemistries, including novel low‐cobalt cathode, organic electrode, and aqueous electrolyte, are discussed. Then, the characteristics of safety performance are analyzed and strategies to enhance safety are subsequently evaluated. Battery recycling is considered as the key factor for a sustainable society and related technologies are present as well. Finally, conclusion and outlook are drawn to shed lights on the further development of sustainable lithium‐ion batteries.

A conformal cooling channel (CCC) is widely employed in the injection mold due to uniform cooling. The cooling efficiency of the epoxy resin mold (ERM) strictly depends on the thermal conductivity since the cooling time directly affects the productivity. According to the practice experience, the material cost of commercial aluminum (Al)-filled epoxy resin is high and the cooling efficiency of the injection mold fabricated by commercial materials is limited to the physical properties. Accordingly, developing an injection mold with high cooling efficiency at low cost is therefore of critical importance. This study develops a low-cost recipe for making injection molds. It was found that both the cooling efficiency and material cost are better than those made with commercial Al-filled epoxy resin. The difference in the cooling time of the injection molded parts between the simulation and experiment is approximately 22%. The remarkable findings of this study are very practical and provide good application prospects in the investment casting industry.

The side reaction and dendrite of a zinc anode in an aqueous electrolyte represent a huge obstacle for the development of rechargeable aqueous Zn batteries. An electrolyte with confined water is recognized to fundamentally stabilize the zinc anode. This work proposes acetamide/zinc perchlorate hexahydrate (AA/ZPH) ionic liquid (IL)-polyacrylamide (PAM) polymer electrolytes, here defined as IL-PAM. The novel Zn2+-conducting IL is able to accommodate trace water and can achieve both high conductivity (15.02 mS cm-1) and alleviation of side reactions (>90% reduction). Cross-linked PAM acts as the three-dimensional framework to suppress dendrites and obtain flexibility. As a result, the Zn anode with IL-PAM can cycle stably over 2000 h with a record highest cumulative capacity of 3000 mAh cm-2 and well-preserved morphology. Based on IL-PAM, the flexible LFP|Zn hybrid batteries can be successfully assembled and operate normally in series and parallel conditions. Moreover, the low volatility of IL and binding forces exerted by the PAM network endues IL-PAM with an anti-dehydration property. In a 50 °C unsealed environment, the weight loss of IL-PAM is about two-fifths of PAM hydrogel and an aqueous electrolyte, and the corresponding hybrid battery with IL-PAM can also prolong a 4 times longer lifespan.

The generation and evolutional behavior of the solid-electrolyte interphase (SEI) fatally dictate the performance of working anodes, especially lithium (Li) anodes. In this Opinion, we describe the critical rationale in understanding competitive SEI formation on a working Li metal anode. First, the fundamentals that determine the competitive SEI-forming reactions at the Li/electrolyte interface are analyzed. Moreover, we elucidate the kinetic competition between SEI growth and Li deposition in the case of exposure to fresh Li surfaces during the Li electroplating process. Several important factors involving electrolyte formulation, current density, and temperature that can intrinsically modulate the kinetic competition are comprehensively summarized. Finally, future research trends regarding dynamic SEI formation and its correlation with the manner of Li electroplating are addressed.

The enhancement factor is one of the key parameters characterizing the phenomenon of surface-enhanced Raman scattering. At present, this parameter is described by an empirical formula or a certain single physical mechanism instead of a unified model of the chemical and electromagnetic enhancement mechanisms. It is necessary to integrate the dual enhancement mechanisms of SERS to more accurately obtain the SERS enhancement factor with molecular selectivity. Therefore, we propose a quantitative model for the prediction of the enhancement factor that includes the two main contributions, metal plasmon resonance and electronic structure. Theoretical analysis and verification by experimental results prove that the new predictive enhancement factor (EF) model of electronic structural energy improves the enhancement factor by approximately 10 times and can be used to calculate the enhancement factors of different molecules on the same substrate material, which can provide molecular selectivity and more accurate EF predictions. This paper presents a theoretical model of the SERS enhancement factor that includes the adsorption of the adsorbed molecules and the surface of the substrate, combines the electromagnetic and chemical enhancement mechanisms for surface-enhanced Raman scattering, and provides a deep comprehension of the phenomenon of surface-enhanced Raman scattering.

There is currently great interest in aqueous rechargeable Zn/MnO2 batteries due to their advantages of low cost, high specific energy density, and environmental friendliness. However, the poor conductivity and low utilization of the MnO2 cathode during the electrochemical reaction are the bottlenecks to achieving high power density and acceptable reversibility. Unlike most studies on the modification of MnO2 cathodes, this work proposes a new bromide–acetate co-mediated multicomponent metal-ion aqueous electrolyte to realize a highly reversible and high-specific capacity two-electron transfer reaction between Mn2+ and MnO2. In particular, extremely fast reaction kinetics is achieved due to the bromide modifier additive, which can incorporate into the solvation shells of the Zn2+ and Mn2+ aquo-complex and weaken their solvation effect. Therefore, not only are ultrahigh-rate performance (32C) and power density of 1770 W kg−1 (based on MnO2) realized, but also a long cycling stability of 2500 cycles (10C) is demonstrated. Raman spectroscopy, FTIR spectroscopy, and DFT calculation further reveal the co-mediation mechanism of bromide and acetate in the fast and reversible transformation between Mn2+ and MnO2. This work accentuates the importance of the electrolyte in aqueous batteries and the great potential of high-performance Zn–MnO2 batteries with low-cost bromide and acetate-based electrolyte for large-scale energy storage.

Despite the clear benefits of Na and S active materials, Na–S hybrid energy storage devices have yet to be exploited, and existing Na–S batteries cannot provide fast kinetics and long-term stabilit...

Lithium-ion batteries with routine carbonate electrolytes cannot exhibit satisfactory fast-charging performance and lithium plating is widely observed at low temperatures. Herein we demonstrate that a localized high-concentration electrolyte consisting of 1.5 M lithium bis(fluorosulfonyl)imide in dimethoxyethane with bis(2,2,2-trifluoroethyl) ether as the diluent, enables fast-charging of working batteries. A uniform and robust solid electrolyte interphase (SEI) can be achieved on graphite surface through the preferential decomposition of anions. The established SEI can significantly inhibit ether solvent co-intercalation into graphite and achieve highly reversible Li+ intercalation/de-intercalation. The graphite | Li cells exhibit fast-charging potential (340 mAh g-1 at 0.2 C and 220 mAh g-1 at 4 C), excellent cycling stability (ca. 85.5 % initial capacity retention for 200 cycles at 4 C), and impressive low-temperature performance.

Graphene oxide (GO) membranes have shown enormous promise in desalination and molecular/ionic sieving. However, the instability of GO membranes in aqueous solutions seriously hinders their practical applications. Herein, we report a novel and simple strategy to fabricate stable GO membranes in water-based environments through the insertion of various metal cations from metal foils (e.g., copper (Cu), iron (Fe), nickel (Ni), and zinc (Zn) foils) and natural deposition. Based on the cation-π, coordination, and electrostatic interaction between metal cations and GO nanosheets, the aqueous stability and mechanical strength of the membranes are significantly improved. The permeation rates for acetone, toluene, and p-xylene molecules across the GO membrane cross-linked by copper ions with a deposition time of 24 h are 0.966, 0.074, and 0.100 mol m-2 h-1, respectively. Moreover, this membrane displays excellent separation performance, and the separation factor of K+/Mg2+ is up to 68.8 in mono-/multivalent metal cation sieving, which indicate the effective molecular/ionic sieving performance. Meanwhile, the ionic sieving of the GO membrane cross-linked by copper ions has excellent repeatability and long-term stability. The versatility of this natural deposition strategy to fabricate GO membranes cross-linked by metal cations is investigated by using Fe foil, Zn foil, and Ni foil as well as other porous substrates such as polyvinylidene fluoride (PVDF), polyethersulfone (PES), and nylon membranes and filter paper. This fabrication strategy also enables low-cost preparation of large-area GO membranes. Therefore, GO membranes cross-linked by metal cations and prepared by this simple metal cation incorporation strategy have large potential application for molecular/ionic sieving in various solution systems.

Dowel type timber joints are popular in timber construction and they can be used in timber trusses and moment resisting frames (i.e. beam-to-column joints). Bearing strength is an important design parameter that influences the strength of each failure mode a joint can experience. Therefore, in order to enhance the load carrying capacity of dowel-type joints, the bearing strength of the timber should be increased. Externally bonded fibre-reinforced polymer (FRP) composites offer effective and rapid retrofit and repair solutions for the joints. As a result, this paper reports a series of tests on fifty single-bolt timbers joints subjected to tension of which 25 joints were made from softwood and 25 from hardwood. Forty of the joints were strengthened with four different arrangements of externally bonded carbon FRP plates representing fibre orientations of 0°, 0°/90°, ±45°and ± 30°to the grain direction. In addition, ten joints served as unstrengthened controls. The test details as well as failure modes, strength and ductility of all test joints are reported in addition to joint strength predictions. Overall, the strengthening schemes adopted were found to enhance the strength of the timber joints although their effectiveness varied. With proper fibre orientation, the strength of the joint was observed to increase by 50% above the control joint. The FRP was also found in cases to alleviate brittle timber failure by preventing premature splitting of the timber.

Highly active and stable catalysts are very crucial for boosting the oxygen evolution reaction (OER) and converting water into clean fuel. Here, we adopt the laser ablation in liquid technique to p...

Sulfide solid electrolytes offer great opportunities to construct solid-state Li metal batteries with high energy density. The high ionic conductivity of well-developed sulfide electrolytes enables solid-state battery to operate at high current rates. However, sulfide electrolytes exhibit severe decomposition in working cells, constituting a significant obstacle for the practical applications of sulfide solid-state electrolytes. The decomposition behaviors of sulfides are complicated and strongly depend on the electrochemical windows, some of which are even regarded reversible during battery cycling. Herein, we investigate the redox behaviors of Li7P3S11 sulfide solid electrolyte under different voltage windows, and their effects on interfacial transport and battery cycle lifetime. Moreover, Li metal | Li4Ti5O12 (LTO) batteries are introduced to further probe the role of multiphase redox reactions on interfacial ion conduction. By regulating the redox behaviors of electrolytes through varying working voltage window, Li | LTO metal batteries enable a rapid charge/discharge process in 10 ​min (6 ​C) and lifespan of 600 cycles at 1 ​C with 85% capacity retention. An all-solid-state Li | LTO metal pouch cell is also assembled and exhibits a stable cycling performance with a capacity of 120 mAh g−1. This work provides understandings about interfacial redox behaviors of sulfide electrolyte, presenting novel insights in the rational design of future solid-state lithium batteries with high-energy/power-density.

Lithium-ion battery has greatly changed our lifestyle and the solid electrolyte interphase (SEI) covered on the graphite anode determines the service life of a battery. The formation method and the formation temperature at initial cycle of a battery determine the feature of the SEI. Herein, we investigate the gap of formation behavior in both a half cell (graphite matches with lithium anode) and a full cell (graphite matches with NCM, short for LiNixCoyMn1−x−yO2) at different temperatures. We conclude that high temperature causes severe side reactions and low temperature will result in low ionic conductive SEI layer, the interface formed at room temperature owns the best ionic conductivity and stability.

A metal-rim-connected inductive coupler with series-none compensation topology is proposed for smartwatch applications. By cross-connecting the receiving coil to the metal rim with a 1 mm slot, the direction of the induced current on the metal rim is transformed to be the same as the current flowing on the receiving coil, leading to a strong magnetic coupling between the transmitting coil and receiving coil. Considering the space limitation in the smartwatch, non-compensation components are needed inside the smartwatch and only a series capacitance is integrated on the transmitter side. A prototype of the proposed inductive coupler has been built and the wireless power transfer through metal rim has been validated via experiment. The experimental results show that the prototype achieves 5 W output power with 87.4% coil-to-coil efficiency.

Lithium (Li) metal, possessing an extremely high theoretical specific capacity (3860 mAh/g) and the most negative electrode potential (−3.040 V vs. standard hydrogen electrode), is one the most favorable anode materials for future high-energy-density batteries. However, the poor cyclability and safety issues induced by extremely unstable interfaces of traditional liquid Li metal batteries have limited their practical applications. Herein, a quasi-solid battery is constructed to offer superior interfacial stability as well as excellent interfacial contact by the incorporation of Li@composite solid electrolyte integrated electrode and a limited amount of liquid electrolyte (7.5 μL/cm2). By combining the inorganic garnet Al-doped Li6.75La3Zr1.75Ta0.25O12 (LLZO) with high mechanical strength and ionic conductivity and the organic ethylene-vinyl acetate copolymer (EVA) with good flexibility, the composite solid electrolyte film could provide sufficient ion channels, sustained interfacial contact and good mechanical stability at the anode side, which significantly alleviates the thermodynamic corrosion and safety problems induced by liquid electrolytes. This innovative and facile quasi-solid strategy is aimed to promote the intrinsic safety and stability of working Li metal anode, shedding light on the development of next-generation high-performance Li metal batteries.

Lithium metal batteries are strongly considered as one of the most promising candidates for next-generation high-performance battery systems. However, the uncontrollable growth of lithium dendrites and the highly reactive lithium metal result in the severe safety risks and the short lifespan for high-energy-density rechargeable batteries. Here, we demonstrate a hydrophobic and ionically conductive ethylene-vinyl acetate (EVA) copolymer layer can not only endow lithium metal anodes with an air-stable and anti-water surface, but also efficiently suppress the lithium-dendrites growth during the electrochemical cycling process. Therefore, the introduction of the EVA copolymer as a bifunctional protection layer simultaneously improves the anti-water/air performance and electrochemical cycling stability of lithium metal anode.