Search

3D interconnected ultrathin CoSe nanosheets are prepared via a hydrothermal synthesis method and utilized as superior battery-like electrode material for the first time. Due to the features of the unique 3D interconnected ultrathin nanosheets with a large BET specific surface area, superior mesoporous structure and good electrical conductivity, the as-resulted 3D interconnected ultrathin CoSe nanosheets manifests a high specific capacity of 70.6 mAh g−1 at 1 A g−1 and remarkable rate performance with 52.8% of capacity retention rate at 100 A g−1 compared with 1 A g−1. Furthermore, a novel aqueous hybrid supercapacitor is assembled by employing 3D interconnected ultrathin CoSe nanosheets and activated carbon as the cathode and anode, respectively. The assembled hybrid device displays a specific energy of 18.6 Wh kg−1 at a specific power of 750 W kg−1 and outstanding cycling life with 95.4% of the initial capacity retention for 20000 cycles at 5 A g−1. These results imply that the unique 3D interconnected ultrathin CoSe nanosheets can be considered as highly potential candidate electrode materials for hybrid supercapacitors.

High-voltage aqueous rechargeable batteries are promising competitors for next-generation energy storage systems with safety and high specific energy, but they are limited by the absence of low-cost aqueous electrolytes with a wide electrochemical stability window (ESW). The decomposition of aqueous electrolytes is mainly facilitated by the hydrogen bond network between water molecules and the water molecules in the solvation sheath. Here, three types of small dipole molecules (small molecules containing a dipole; glycerol (Gly), erythritol (Et), and acrylamide (AM)) are reported to develop aqueous electrolytes with high safety and wide ESW (over 2.5 V) for aqueous lithium-, sodium-, and zinc-ion batteries, respectively. The solvation-sheath structures are explored by ab initio molecular dynamics (MD) simulations, demonstrating that three types of dipole molecules deplete the water molecules in the solvation sheath of the charge carrier and break the hydrogen bond network between the water molecules, thus effectively expanding the ESW. A battery constructed from lithium titanate and lithium manganate in Gly-containing electrolyte exhibits an output voltage of 2.45 V and retains a specific capacity of 119.6 mAh g-1 after 400 cycles. This work provides another strategy for exploiting low-cost high-voltage electrolytes for aqueous energy-storage systems.

Aqueous graphite-based dual ion batteries have unique superiorities in stationary energy storage systems due to their non-transition metal configuration and safety properties. However, there is an absence of thorough study of the interactions between anions and water molecules and between anions and electrode materials, which is essential to achieve high output voltage. Here we reveal the four-stage intercalation process and energy conversion in a graphite cathode of anions with different configurations. The difference between the intercalation energy and hydration energy of bis(trifluoromethane)sulfonimide makes the best use of the electrochemical stability window of its electrolyte and delivers a high intercalation potential, while BF

Precious metal Pd has the intrinsic superiority in adsorbing N2 molecule and wrecking the high cleavage barrier of the N≡N bond, however, its over-strong adsorption ability is unfavorable to the desorption of the produced NH3 during the electrochemical N2 reduction (NRR), which weighs heavily against the NH3 productivity. Here we demonstrate that the high electron-density of acetylene linkages of hydrogen substituted graphdiyne can regulate the nitrogen adsorption and NH3 desorption on the active Pd sites (Pd/HsGDY), resulting in impressive electrocatalytic NRR performance. The optimized Pd/HsGDY features an ultrahigh Faraday efficiency of 44.45% and an NH3 yield of 115.93 mg g−1 h−1 (or 11.59 µg cm−2 h−1). Density functional theory calculations reveal that the acetylene linkages in HsGDY can tune the d band center of active Pd atoms by downward shifting it from the Fermi level. This favors the hydrogenation of nitrogen on HsGDY-tuned Pd sites and benefits the desorption of produced NH3 from the catalyst surface to recover active sites induced by heat dissipation during the exothermic hydrogenation processes, resulting in a selectively facilitated electrosynthesis of NH3.

High specific capacity and long cycling life of anode materials still remain major challenges in the development of sodium-ion batteries (SIBs). Nowadays, transition metal phosphides have been reckoned as promising anodes in view of their high theoretical specific capacities, low potential for sodium storage, and superior conductivity. Herein, molybdenum phosphide (MoP) nanorods wrapped with thin carbon layer have been prepared and applied as an anode for SIBs. By utilizing in situ X-ray diffraction technology, a conversion-type mechanism of MoP anode has been disclosed. This kind of MoP electrode exhibits extraordinary electrochemical properties, including excellent cycling performance with a discharge capacity of 398.4 mA h g–1 at a current density of 100 mA g–1 after 800 cycles, and remarkable rate capabilities, which remain 104.5 mA g–1 at 1600 mA h g–1 even after 10 000 loops. The distinguished performances stem from synergetic merits of the morphology, structure, and mechanism of MoP. It is expected...

Rod-like α-MoO 3 is successfully designed by alternating voltage induced electrochemical synthesis (AVIES) approach. The morphology and texture of MoO 3 is effectively controlled by applying various calcination temperature of 300–600 °C. Notably, the α-MoO 3 microrods growing along [001] direction have the high aspect ratio, and the randomly stacked structure can facilitate the charge transfer and offer more active sites for sodium storage. When utilized for sodium-ion batteries, it presents the high charge capacities of 305 mAh g −1 at 1C and 143 mAh g −1 at 10C. Even after 3000 cycles at 10C, a significant capacity of 108 mAh g −1 is still delivered, highlighting its marvelous electrochemical properties. This work may be a compelling exploration for developing metal/metal oxides materials for sodium storages by AVIES.

Antimony represents a class of unique functional materials in sodium-ion batteries with high theoretical capacity (660 mA h g–1). The utilization of carbonaceous materials as a buffer layer has been considered an effective approach to alleviate rapid capacity fading. Herein, the antimony/nitrogen-doping porous carbon (Sb/NPC) composite with polyaniline nanosheets as a carbon source has been successfully achieved. In addition, our strategy involves three processes, a tunable organic polyreaction, a thermal annealing process, and a cost-effective reduction reaction. The as-prepared Sb/NPC electrode demonstrates a great reversible capacity of 529.6 mA h g–1 and an outstanding cycling stability with 97.2% capacity retention after 100 cycles at 100 mA g–1. Even at 1600 mA g–1, a superior rate capacity of 357 mA h g–1 can be retained. Those remarkable electrochemical performances can be ascribed to the introduction of a hierarchical porous NPC material to which tiny Sb nanoparticles of about 30 nm were well-wra...

The conventional strategies for obtaining S/N-codoped carbon materials suffer from a series of problems caused by their complicated experimental procedures. Here, S,N-codoped carbon nanosheets were firstly prepared by a solvent-free one-pot method, displaying an ultra-thin sheet-like structure, a tunable interlayer distance ranging from 0.37 nm to 0.41 nm, and a large surface area up to 809 m2 g−1. When they were used as an anode for sodium-ion batteries (SIBs), an outstanding sodium-ion storage performance of 380 mA h g−1 was acquired at 100 mA g−1, which can be attributed to the expanded interlayer distance caused by the introduction of the large covalent radius-sulfur. The initial coulombic efficiency improved to 60.9%, which may benefit from N-doping. Most importantly, an excellent rate capability of ∼178 mA h g−1 was observed at a current density of 5 A g−1 after 5000 cycles, which is among best of the state-of-the-art carbon-based SIBs. Interestingly, the morphology of the obtained carbon materials can be tuned from bulk to flake by adjusting the sulfur content or temperature. Given this, this work provides a new method to construct co-doped carbon (especially tri-doped and multi-doped carbon) and shows that the strategy of co-doping of heteroatoms can effectively optimize the nano/microstructure and enhance the rate capability of the carbon materials.

Anatase TiO 2 nanopores are successfully prepared through alternating voltage induced electrochemical synthesis (AVIES) approach at room temperature. When utilizing TiO 2 nanoporous materials as an anode for Na-ion battery, it delivers a reversible charge-discharge capacity of around 180 mA h g −1 at 0.2 C (67 mA g −1 ) after 200 cycles. Meanwhile, it also shows a good cycling performance and a high rate capability due to unique nanoporous structures, which promote electrolyte wetting and facilitate diffusion of Na + . Additionally, cyclic voltammetry demonstrate that the sodium-ion storage of as-prepared TiO 2 is a cooperative control behavior of diffusion and capacitance, but mainly controlled by capacitive behavior, which further facilitates a rapid (de-)intercalation of Na + .

Nonmetallic ammonium (NH

Degradable energy storage systems (ESSs) have been proposed to tackle increasing e-wastes such as heavy metals and toxic organic electrolytes. However, currently reported degradable ESSs are scarce because it is very difficult to make all of the electrochemical components degradable as they must be stable for energy storage. Here, we designed an all-component degradable and rechargeable Zn-MXene capacitor with outstanding anti-self-discharge function using zinc nanosheets and Ti

Weak binding and affinity between the conductive support and iodine species leads to inadequate electron transfer and the shuttle effect. Herein, redox kinetics and duration are significantly boosted by introducing a Nb2 CTX host that is classified as a layered 2D Nb-based MXene. With a facile electrodeposition strategy, initial I- ions are electrically driven to insert in the nanosized interlayers and are electro-oxidized in situ. Linear I2 is firmly confined inside and benefits from the rapid charge supply from the MXene. Consequently, an aqueous Zn battery based on a Zn metal anode and ZnSO4 electrolyte delivers an ultraflat plateau at 1.3 V, which contributes to 84.5% of the capacity and 89.1% of the energy density. Record rate capability (143 mAh g-1 at 18 A g-1 ) and lifespan (23 000) cycles are achieved, which are far superior to those of all reported aqueous MXenes and I2 -metal batteries. Moreover, the low voltage decay rate of 5.6 mV h-1 indicates its superior anti-self-discharge properties. Physicochemical analyses and density functional theory calculations elucidate that the localized electron transfer and trapping effect of the Nb2 CTX MXene host are responsible for enhanced kinetics and suppressed shuttle behavior. This work can be extended to the fabrication of other I2 -metal batteries with long-life-time expectations.

Hydrogen-substituted graphdiyne (HsGDY), as a new rising star of carbon materials family, demonstrates high conjugation, robust chemical stability, and versatility for modification. However, grand challenges, including low production rate, disordered topology, and amorphous structure, greatly hinder its large-scale applications. Herein, we report, for the first time, the scalable synthesis (up to gram-level) of two-dimensional (2D) crystalline HsGDY nanosheets with Zn as a substrate. Moreover, as a metal-free catalyst for electrochemical N2 fixation, 2D HsGDY achieves an ultrahigh yield of 103 μg h−1 mg−1cat. with a potential of −0.2 V vs reversible hydrogen electrode (RHE), which is comparable with that of noble metals and single-atom catalysts. Different from the heteroatom active sites in carbon-based catalysts reported before, the inner alkynyl C itself in 2D HsGDY was identified as the active site, which adsorbs and activates N N due to the positive charge and high spin density triggered by the slight O doping in the form of C O at the outer alkynyl C. We believe that this Zn-templated scalable production of high-quality HsGDY paves the way for its large-scale production and provides a new playground for the multiple research fields.

Gray-colored Mo 6+ -doped anatase TiO 2 is prepared uniformly with particle size of 10–20 nm, and is firstly employed as anode material in sodium-ion batteries (SIBs), presenting excellent electrochemical performances. It delivered reversible specific capacities of 231.8 mAh g −1 at 0.1 C (33.5 mA g −1 ) after 100 cycles and 108.3 mAh g −1 at 5 C (1.68 A g −1 ), comparing to 170.5 mAh g −1 at 0.1 C and only 41.7 mAh g −1 at 5C for the bare TiO 2 . The improved electrochemical performances might be beneficial from the doping of Mo 6+ , which can effectively enhance the conductivity of TiO 2 resulting from induced conduction band electrons, interstitial oxygen defects and vacancies. In addition, the doping can also lead to the lattice expansion, which can facilitate the diffusion of Na + . In combination with natural abundance and environmental benignity, Mo 6+ -doped TiO 2 can be expected to be utilized as an anode material for enhanced sodium storage.

3D porous carbon encapsulated SnO2 nanoparticles composite (SnO2-PC) prepared by an efficient in situ methodology was applied as anode for sodium ion batteries (SIBs). It delivered a high reversible specific capacity of 280.1 mAh g−1 after 250 cycles at a current density of 100 mA g−1, with ultrahigh capacity retention of 91.63%. Notably, it can Exhibit 100 mAh g−1 after 1000 cycles even at a high current density of 1600 mA g−1. These greatly enhanced electrochemical properties of SnO2-PC composite can be attributed to the superior structure that the electrical conductivity of the composite was improved by the porous carbon matrix, moreover, it can serve as a cushion during the process of Na ion insertion/extraction into the composite. Significantly, this kind of in situ synthesis method is portable for other similar composite.

Carbon-coated rutile titanium dioxide (CRT) was fabricated through an in-situ pyrolysis of titanium-based metal organic framework (Ti8O8(OH)4[O2CC6H4CO2]6) crystals. Benefiting from the Ti O C skeleton structure of titanium-based metal organic framework, the CRT possesses abundant channels and micro/mesopores with the diameters ranging from 1.06 to 4.14 nm, shows larger specific surface area (245 m2 g−1) and better electronic conductivity compared with pure titanium dioxide (12.8 m2 g−1). When applied as anode material for sodium-ion batteries, the CRT electrode exhibits a high cycling performance with a reversible capacity of ∼175 mAh g−1 at 0.5 C-rate after 200 cycles, and obtains an excellent rate capability of ∼70 mAh g−1 after 2000 cycles even at a specific current of 3360 mA g−1(20 C-rate). The outstanding rate capability can be attributed to the carbon-coated structure, which may effectively prevent aggregation of the titanium dioxide nanoparticles, accelerate the mass transfer of Na+ and speed up the charge transfer rate. Considering these advantages of this particular framework structure, the CRT can serve as an alternative anode material for the industrial application of SIBs.

Carbon dots inducing petal-like rutile TiO2 wrapped by ultrathin graphene-rich layers are proposed to fabricate superior anodes for sodium-ion batteries, featuring high-rate capabilities and long-term cyclelife, benefiting from promoted electron transport and a shortened Na+ diffusion length. High capacities of 144.4 mA h g-1 (at 837.5 mA g-1 ) after 1100 cycles and 74.6 mA h g-1 (at 3350 mA g-1 ) after 4000 cycles are delivered outstandingly.

Olive-shaped anatase TiO2 with tunable sizes in nanoscale are designed employing polyvinyl alcohol (PVA) as structure directing agents to exert dramatic impacts on structure shaping and size manipulation. Notably, the introduced PVA simultaneously serves as carbon sources, bringing about a homogenous carbon layer with intimate coupling interfaces for boosted electronic conductivity. Constructed from tiny crystalline grains, the uniformly dispersed carbon-coated TiO2 nano-olives (TOC) possess subtle loose structure internally for prompt Na+ transportations. When utilized for sodium-ion storage, the size effects are increasingly significant at high charge–discharge rates, leading to the much superior rate performances of TOC with the smallest size. Bestowed by the improved Na+ adsorption and diffusion kinetics together with the promoted electron transfer, it delivers a high specific capacity of 267 mAh g−1 at 0.1 C (33.6 mA g−1) and sustains 110 mAh g−1 at a rather high rate of 20 C. Even after cycled at 10 C over 1000 cycles, a considerable capacity of 125 mAh g−1 with a retention of 94.6% is still obtained, highlighting its marvelous long-term cyclability and high-rate capabilities.

A facile route to improve the lithium-storage properties of flake graphite (FG) is proposed through coating pyrolysis carbon from polyvinylidene fluoride (PVDF) assisted by KOH activation. The interplanar distance between the graphene sheets of activated PVDF/FG is enlarged, effectively suppressing the electrode deformation during lithium (de)-intercalation. More edge and porous structures of PVDF/FG arising from KOH activation on graphite flakes contribute to improved electron and ion transport, leading to great improvement in its rate and cycling performances. The initial specific capacity of the activated PVDF/FG is 476.6 mAh g −1 at 50 mA g −1 and when the current increases to 1000 mA g −1 , the value still retains 142.6 mAh g −1 .

Cube-shaped porous carbon (CPC) was obtained from the carbonization of MOF-5 (Zn4O(OOCC6H4COO)3) crystals and shows abundant micro/mesopores, high mechanical strength, largest surface area (2316 m2 g−1, BET method) and good electrical conductivity (a high weight ratio 98.17/1.83 of C/O). When utilized as anode material for sodium-ion batteries, the CPC presents a high overall sodium storage capacity ∼240 mAh g−1 at a current density of 100 mA g−1 after 100 cycles, and maintains a high specific capacity of 100 mAh g−1 after 5000 cycles at a current density of 3200 mA g−1. For the advantages of this unique carbon framework structure, the CPC might be a promising anode material for the application of SIBs.

Hierarchical anatase TiO2 homogeneously tuned by using carbon through Ti–C bonds has been designed, exploiting carbon quantum dots as uniform carbon additives and functionalization inducers for structure tailoring and surface modification. The fabricated pinecone-like structure constructed by ultrafine subunits presents a highly increased surface area (202.4 m2 g−1) and abundant mesopores. Surface bonded carbon significantly boosts its electronic conductivity derived from both the conductive carbon and accompanied oxygen vacancies. When utilized in sodium-ion batteries, it delivers a high reversible specific capacity of 264.1 mA h g−1 at a rate of 0.1C (33.6 mA g−1) and still maintains 108.2 mA h g−1 even after 2000 cycles at 10C with a retention of 94.7% outstandingly. Notably, its Na+ intercalation pseudocapacitive behavior is enhanced by the modulated TiO2/carbon interfaces, facilitating a fast (de-)sodiation process. Combining the elaborate hierarchical structure with the unique surface composition, synergetic merits are noticed when the promoted kinetics, improved electronic conductivity, increased electrolyte penetration areas and shortened Na+ diffusion length are achieved simultaneously, giving rise to remarkable high-rate capabilities and long-term cyclability.

The practical application of Li‐rich Mn‐based oxide cathode is predominately retarded by the capacity decline and voltage fading, associated with the structure distortion and anionic redox reactions. Here, a linkage‐functionalized modification approach to tackle these challenges via a synchronous lithium oxidation strategy is reported. The doping of Ce in the bulk phase activates the pseudo‐bonding effect, effectively stabilizing the lattice oxygen evolution and suppressing the structure distortion. Interestingly, it also induces the formation of spinel phase Li4Mn5O12 in the subsurface, which in turn constructs the phase boundaries, thereby arousing the interior self‐built‐in electric field to prevent the outward migration of bulk oxygen anions and boost the charge transfer. Moreover, the formed coating layer Li2CeO3 with oxygen vacancies accelerates Li+ diffusion and mitigates electrolyte cauterization. The corresponding cathode exhibits superior long‐cycle stability after 300 cycles with only a 0.013% capacity drop and 1.76 mV voltage decay per cycle. This work sheds new light on the development of Li‐rich Mn‐based oxide cathodes toward high energy density applications.

Rechargeable aqueous zinc batteries have attracted enormous attention due to the distinctively economic and environmental advantages. However, the present zinc batteries delivered sloping voltage profiles based on the dominant mechanism of Zn ion intercalation. Typically, a Zn–V2O5 battery exhibits a discharge slope of ~4.3 V/(Ah g−1) and a slope of ~1.5 V/(Ah g−1) is observed for MnO2 cathodes. Furthermore, the rate capacity based on intercalation is limited. Here we report a highly flat voltage profile for a reversible alkaline zinc battery with α-Bi2O3 as the cathode. Different from the conventional zinc batteries, zinc-α-Bi2O3 batteries possess a first-order phase transition process that is the responsible cause of their outstanding performance, such as an ultra-flat output voltage [slope: ~0.1 V/(Ah g−1)], a high discharge capacity of 323 mAh g−1 at 0.1 A g−1 and excellent rate capacity with a 155 mAh g−1 capacity even at 20A g−1 (61C). In addition, a high areal energy density of 1.5 mWh cm−2 is achieved at power density of 4.4 mW cm−2. Moreover, the quasi-solid-state Zn-α-Bi2O3 battery is also fabricated using a sodium polyacrylate (PANa) as the hydrogel electrolyte, exhibiting promising application as power source for flexible devices.

Nonmetallic ammonium (NH4+) ions are applied as charge carriers for aqueous batteries, where hexagonal MoO3 is initially investigated as an anode candidate for NH4+ storage. From experimental and first-principle calculated results, the battery chemistry proceeds with reversible building-breaking behaviors of hydrogen bonds between NH4+ and tunneled MoO3 electrode frameworks, where the ammoniation/deammoniation mechanism is dominated by nondiffusion-controlled pseudocapacitive behavior. Outstanding electrochemical performance of MoO3 for NH4+ storage is delivered with 115 mAh g(-1) at 1 C and can retain 32 mAh g(-1) at 150 C. Furthermore, it remarkably exhibits ultralong and stable cyclic performance up to 100 000 cycle with 94% capacity retention and high power density of 4170 W kg(-1) at 150 C. When coupled with CuFe prussian blue analogous (PBA) cathode, the full ammonium battery can deliver decent energy density 21.3 Wh kg(-1) and the resultant flexible ammonium batteries at device level are also pioneeringly developed for potential realistic applications.

Zinc batteries are at the forefront of aqueous energy storage due to their intrinsic safety and low cost. Various vanadium oxides stand out among the few cathode candidates. Herein, we demonstrate a new heterogeneous vanadium oxide nanowire with V2O5·nH2O shell and V3O7·H2O core, named h-VOW, as a promising cathode candidate for Zn batteries. Thanks to the synergies of multivalent states of vanadium elements associated with inherent high conductivity, in an aqueous electrolyte, h-VOW/Zn battery delivers high discharge capacity (455 mAh g−1 at 0.1 A g−1), energy density (340 Wh kg−1) and power density (9105 W kg−1). Moreover, the gel electrolyte imparts satisfied deformability and weather resistance to the flexible quasi-solid-state battery, allowing it to withstand extremely harsh conditions without catastrophic failure.

Due to the high theoretical capacity of 946 mAh g–1, Sb2S3 can be employed as promising electrode material for sodium-ion batteries (SIBs). Herein, the sodium storage behaviors of one-dimensional (1D) Sb2S3-based materials (Sb2S3 and Sb2S3@C rods) are successfully studied for the first time, displaying good cyclability and rate capability owing to their unique morphology and structure. Specifically, the Sb2S3@C rods electrode presents greatly enhanced electrochemical properties, resulting from the introduction of thin carbon layers which can effectively alleviate the strain caused by the large volume change and simultaneously improve the conductivity of electrode during cycling. At a current density of 100 mA g–1, it delivers a high capacity of 699.1 mAh g–1 after 100 cycles, which corresponds to 95.7% of the initial reversible capacity. Even at a high current density of 3200 mA g–1, the capacity can still reach 429 mAh g–1. This achievement may be a significant exploration for develpoing novel 1D Sb-base...

Cypress leaf-like Sb (CL-Sb) was obtained via a facile chemical replacement reaction. The prepared CL-Sb was firstly applied as an anode material for sodium-ion batteries, displaying outstanding electrochemical performances with superior rate capability and excellent cycle stability due to its unique morphology.

Liquid phase exfoliation of few-layer phosphorene (FL-P) is extensively explored in recent years. Nevertheless, their deficiencies such as ultralong sonication time, limited flake size distribution, and uncontrollable thicknesses are major hurdles for the development of phosphorene-based materials. Herein, electrochemical cationic intercalation has been introduced to prepare phosphorene, through which large-area FL-P without surface functional groups can be efficiently attained (less than 1 h). More importantly, its layer number (from 2 to 11 layers) can be manipulated by changing the applied potential. The as-obtained phosphorene delivers superior sodium-storage performances when directly utilized as an anode material in sodium-ion batteries. This electrochemical cation insertion method to prepare phosphorene should greatly facilitate the development of phosphorene-based technologies. Moreover, this work provides the possibility for the scalable preparation of monolayer 2D materials by exploring intercalation ions. Additionally, the successful electrochemical exfoliation of phosphorene can promote the application of electrochemical exfoliation in other 2D materials.

Building aqueous acidic batteries is in its infancy. There are several sporadic attempts that show desirable electrochemical performance, especially rate stability and high power density. The direct use of a metal anode is regarded as the best protocol for fabricating metal-based batteries. However, introducing an acid-tolerant and electrochemically reversible metal anode into an acidic aqueous battery system remains a considerable challenge. In this work, copper (Cu) metal is used as a reversible metal anode to match acidic regimes with a nearly 100% deposition-dissolution efficiency. The reaction kinetics and mechanism of the Cu anode can be regulated by protons with 400% kinetic acceleration compared with a mild electrolyte. In addition, the anode exhibits a dendrite-free morphology after cycling due to the surface roughening effect, which is different from the morphologies of widely used Zn- and Li-metal anodes. When coupled with the Prussian blue analog as cathodes, the battery delivers ultrafast kinetics of 1830 W kg-1 at 75 C, which is comparable to the power performance of supercapacitors. Long-term cyclic stability is evaluated, where the capacity retention is 85.6% after 5000 cycles. Finally, flexible fiber-shaped acidic Cu-based batteries are demonstrated for potential wearable applications.

The dendritic issue in aqueous zinc-ion batteries (ZBs) using neutral/mild electrolytes has remained an intensive controversy for a long time: some researchers assert that dendrites severely exist while others claim great cycling stability without any protection. This issue is clarified by investigating charge/discharge-condition-dependent formation of Zn dendrites. Lifespan degradation (120 to 1.2 h) and voltage hysteresis deterioration (134 to 380 mV) are observed with increased current densities due to the formation of Zn dendrites (edge size: 0.69-4.37 µm). In addition, the capacity is also found to remarkably affect the appearance of the dendrites as well. Therefore, at small current densities or loading mass, Zn dendrites might not be an issue, while the large conditions may rapidly ruin batteries. Based on this discovery, a first-in-class electrohealing methodology is developed to eliminate already-formed dendrites, generating extremely prolonged lifespans by 410% at 7.5 mA cm-2 and 516% at 10 mA cm-2 . Morphological analysis reveals that vertically aligned Zn dendrites with sharp tips gradually become passivated and finally generate a smooth surface. This developed electrohealing strategy may promote research on metal dendrites in various batteries evolving from passive prevention to active elimination, rescuing in-service batteries in situ to achieve elongated lifetime.

Because of financial constraints, many transit agencies are trying to balance their budgets and provide an efficient transit network and services. This paper presents an improved model for feeder bus network development problems. The proposed approach consists of three main components: (a) an initial solution generation procedure, (b) a network features determination procedure, and (c) a solution search procedure. The tabu search is used as a metaheuristic method in the solution search procedure to find an optimal solution according to a given set of feasible solutions. The input for the new feeder bus network development problem includes the street network, demands from origins to the suburban rail station, and related parameters. The output demonstrates an optimized feeder bus network system and service frequencies for each route. The results show that the proposed method can be used by transit planners to optimize feeder bus systems that provide access to rail stations and other activity centers.

Carbon dots inducing petal-like rutile TiO

Highway–rail crossing safety is a critical issue, highlighted by the recently enacted Rail Safety Improvement Act (by the U.S. Congress. This article documents a national survey of peer state agencies as part of the effort to better understand the current issues of highway–rail grade crossing inspection and best practices in vegetation blockage clearance in the visibility triangle. The authors conducted an extensive literature review, in-depth dialogs with a few selected agencies, and focused on case studies to obtain realistic assessments of current practices in highway–rail grade crossing inspections. Potential issues and concerns in the implementation of the Rail Safety Improvement Act are highlighted.

Recently, sodium-ion batteries (SIBs) are extensively explored and are regarded as one of the most promising alternatives to lithium-ion batteries for electrochemical energy conversion and storage, owing to the abundant raw material resources, low cost, and similar electrochemical behavior of elemental sodium compared to lithium. Metal-organic frameworks (MOFs) have attracted enormous attention due to their high surface areas, tunable structures, and diverse applications in drug delivery, gas storage, and catalysis. Recently, there has been an escalating interest in exploiting MOF-derived materials as anodes for sodium energy storage due to their fast mass transport resulting from their highly porous structures and relatively simple preparation methods originating from in situ thermal treatment processes. In this Review, the recent progress of the sodium-ion storage performances of MOF-derived materials, including MOF-derived porous carbons, metal oxides, metal oxide/carbon nanocomposites, and other materials (e.g., metal phosphides, metal sulfides, and metal selenides), as SIB anodes is systematically and completely presented and discussed. Moreover, the current challenges and perspectives of MOF-derived materials in electrochemical energy storage are discussed.

In the case of rapid development of domestic civil aviation, they are investigated in detail that the trend of In Flight Shut-down (IFSD) of aero engines, the composition of domestic aero engines and the existing analysis method on IFSD. Refer to the Total Quality Management method, the analysis tree of risk sources in IFDS cased is established. And the data-driven method on risk sources analysis in aero engine IFSD is given, based on the grey relation grade. The real data of IFSD cases are used and Type A aero engine is chosen to certify the effectiveness and correctness of the method presented in this paper combined the data in Service Difficulty Report system.

Due to the high theoretical capacity of 946 mAh g(-1), Sb2S3 can be employed as promising electrode material for sodium-ion batteries (SIBs). Herein, the sodium storage behaviors of one-dimensional (1D) Sb2S3-based materials (Sb2S3 and Sb2S3@C rods) are successfully studied for the first time, displaying good cyclability and rate capability owing to their unique morphology and structure. Specifically, the Sb2S3@C rods electrode presents greatly enhanced electrochemical properties, resulting from the introduction of thin carbon layers which can effectively alleviate the strain caused by the large volume change and simultaneously improve the conductivity of electrode during cycling. At a current density of 100 mA g(-1), it delivers a high capacity of 699.1 mAh g(-1) after 100 cycles, which corresponds to 95.7% of the initial reversible capacity. Even at a high current density of 3200 mA g(-1), the capacity can still reach 429 mAh g(-1). This achievement may be a significant exploration for develpoing novel 1D Sb-based materials or metal sulfide SIBs anodes.