Utilizing MOFs Melt-Foaming to Design Functionalized Carbon Foams for 100% Deep-Discharge and Ultrahigh Capacity Sodium Metal Anodes.

Meltable metal-organic frameworks (MOFs) offer significant accessibility to chemistry and moldability for developing carbon-based materials. However, the scarcity of low melting point MOFs poses challenges for related design. Here, we propose a MOFs melt-foaming strategy toward Ni single atoms/quantum dots-functionalized carbon foams (NiSA/QD@CFs).

Surfactant-assisted molecular-level tunning of phenol-formaldehyde-based hard carbon microspheres for high-performance sodium-ion batteries.

The phenol-formaldehyde (PF) resin is an economical precursor for spherical hard carbon (HC) anodes for sodium-ion batteries (SIBs). However, achieving precise molecular-level control of PF-based HC microspheres, particularly for optimizing ion transport microstructure, is challenging. Here, a sodium linoleate (SL)-assisted strategy is proposed to enable molecular-level engineering of PF-based HC microspheres.

Charge Dynamics Engineering Sparks Hetero-Interfacial Polarization for an Ultra-Efficient Microwave Absorber with Mechanical Robustness.

Microwave absorbers with high efficiency and mechanical robustness are urgently desired to cope with more complex and harsh application scenarios. However, manipulating the trade-off between microwave absorption performance and mechanical properties is seldom realized in microwave absorbers. Here, a chemistry-tailored charge dynamic engineering strategy is proposed for sparking hetero-interfacial polarization and thus coordinating microwave attenuation ability with the interfacial bonding, endowing polymer-based composites with microwave absorption efficiency and mechanical toughness.

Interlayer Sodium Plating/Stripping in Van der Waals-Layered Quantum Dot Superstructure.

Assembling quantum dots (QDs) into van der Waals (vdW)-layered superstructure holds great promise for the development of high-energy-density metal anode. However, designing such a superstructure remains to be challenging. Here, a chemical-vapor Oriented Attachment (OA) growth strategy is proposed to achieve the synthesis of vdW-layered carbon/QDs hybrid superlattice nanosheets (Fe S @CNS) with a large vdW gap of 3 nm.

Na Storage Activity or Inertness of P-Configurations in N, P Dual-Doped Carbon Nanofibers: Bulk vs Surface.

Heteroatom doping is an effective method to improve the electrochemical properties of hard carbon anodes for sodium-ion batteries. However, the different roles of surface and bulk heteroatoms in Na storage have not been explored much. Herein, N, P dual-doped carbon nanofibers (NP-CNFs) with high doping contents and low surface area are designed to clarify the above issue.

Borderline Metal Centers on Nonporous Metal-Organic Framework Nanowire Boost Fast Li-Ion Interfacial Transport of Composite Polymer Electrolyte.

Metal-organic frameworks (MOFs) fillers are emerging for composite polymer electrolytes (CPEs). Enhancing Lewis acid-base interaction (LABI) among MOFs, polymer and Li-salt is expected to promote Li -transport. However, it is unclear how to customize a strong LABI interface.

Carbon-Confined Two-Dimensional Sodiophilic Sites Boosted Dendrite-Free Sodium Metal Anodes.

Carbon-supported sodium metal anodes (SMAs) have attracted growing interest in next-generation energy storage applications. Sodiophilic sites on carbon hosts such as foreign metal/metal compounds are critical for suppressing Na dendrite growth. However, the foreign active materials are mostly restricted to nanoparticle-like structures, which suffer from severe agglomeration and low metal utilization.

Lithiophilic onion-like carbon spheres as lithium metal uniform deposition host.

Lithium metal is considered as a promising anode material for next-generation secondary batteries, owing to its high theoretical specific capacity (3860 mA h g). Nevertheless, the practical application of Li in lithium metal batteries (LMBs) is hampered by inhomogeneous Li deposition and irreversible "dead Li", which lead to low coulombic efficiency (CE) and safe hazards. Designing unique lithiophilic structure is an efficient strategy to control Li uniformly plating /stripping.

Binary self-assembly of ordered BiSe/BiOSe lamellar architecture embedded into CNTs@Graphene as a binder-free electrode for superb Na-Ion storage.

With the development of various flexible electronic devices, flexible energy storage devices have attracted more research attention. Binder-free flexible batteries, without a current collector, binder, and conductive agent, have higher energy density and lower manufacturing costs than traditional sodium-ion batteries (SIBs). However, preparing binder-free anodes with high electrochemical performance and flexibility remains a great challenge.

Integrating Multi-Heterointerfaces in a 1D@2D@1D Hierarchical Structure via Autocatalytic Pyrolysis for Ultra-Efficient Microwave Absorption Performance.

Developing microwave absorption (MA) materials with ultrahigh efficiency and facile preparation method remains a challenge. Herein, a superior 1D@2D@1D hierarchical structure integrated with multi-heterointerfaces via self-assembly and an autocatalytic pyrolysis is designed to fully unlock the microwave attenuation potential of materials, realizing ultra-efficient MA performance. By precisely regulating the morphology of the metal organic framework precursor toward improved impedance matching and intelligently integrating multi-heterointerfaces to boosted dielectric polarization, the specific return loss value of composites can be effectively tuned and optimized to -1002 dB at a very thin thickness of 1.

Antiblocking Heterostructure to Accelerate Kinetic Process for Na-Ion Storage.

Heterostructures are attracting increasing attention in the field of sodium-ion batteries. However, it is still unclear whether any two monophase components can be used to construct a high-performance heterostructure for sodium-ion batteries, as well as the kind of heterostructures that can boost electrochemical performances. In this study, based on classical semiconductor theories on antiblocking and blocking interfaces, attempts are made to answer the abovementioned queries.

Achieving Slope-Reigned Na-Ion Storage in Carbon Nanofibers by Constructing Defect-Rich Texture by a Cu-Activation Strategy.

Hard carbons have shown promising application potential as anode materials for sodium-ion batteries (SIBs), but adjusting the texture of hard carbons to manipulate their electrochemical behaviors remains a great challenge. In this work, a Cu-activation strategy is developed to control the defects of hard carbon nanofibers to achieve slope-reigned Na-ion storage behaviors. This method can effectively create defect-rich carbon texture by employing a small amount of Cu(NO) as an activator but cannot induce an increase in the surface area.

Two-Dimensional NiSe/N-Rich Carbon Nanocomposites Derived from Ni-Hexamine Frameworks for Superb Na-Ion Storage.

Design of functional carbon-based nanomaterials from metal-organic frameworks (MOFs) has attracted soaring interests in recent years. However, a MOF-derived strategy toward two-dimensional (2D) nanomaterials remains a great challenge. In this work, we develop a layered Ni-hexamine framework as efficient precursor to prepare a 2D NiSe/N-rich carbon nanocomposite by a simple pyrolysis and subsequent selenization process.

Graphene-Loaded BiSe: A Conversion-Alloying-type Anode Material for Ultrafast Gravimetric and Volumetric Na Storage.

Sodium-ion battery (SIB) has been a promising alternative for sustainable electrochemical energy-storage devices. However, it still needs great efforts to develop electrode materials with ultrafast gravimetric and volumetric Na-storage performance, due to difficult balance between Na-ion diffusion kinetics and pressing density of materials. In this work, BiSe/graphene composites, synthesized by a selenization reaction, are investigated as anode materials for SIBs.

Thermal-exfoliated synthesis of N-rich carbon-based nanosheets from layered bulk crystals of a metal-hexamine framework.

We develop a general strategy for the design of a series of 2D N-rich carbon-based nanomaterials through the thermal exfoliation of layered metal-hexamine framework microcrystals. By a facile pyrolysis, the sharply generated gases escape from the layered precursors, leading to the exfoliation of the layers and successful preparation of 2D carbon-based nanomaterials. This strategy can readily skip the complicated morphology engineering process of 2D metal-organic frameworks to produce 2D N-rich carbon-based nanomaterials on a large scale.

Achieving Ultrafast and Stable Na-Ion Storage in FeSe Nanorods/Graphene Anodes by Controlling the Surface Oxide.

Designing transitional metal selenides (TMSes) with superior rate and cyclic performance for sodium-ion storage remains great challenges. To achieve this task, the influence of surface oxides on Na-ion storage behavior of FeSe is investigated by designing FeSe with varying oxide content. It is found that surface oxide has an inhibitory effect on the activity of FeSe.

Crystallization-Induced Morphological Tuning Toward Denim-like Graphene Nanosheets in a KCl-Copolymer Solution.

Although nucleation and crystallization in solution-processed materials synthesis is a natural phenomenon, the morphology design of graphene nanosheets by controlling the dual crystallization has not been established. In this work, we systematically demonstrate how the dual crystallization of ice and potassium chloride induces the morphological variation of the freeze-dried scaffold from fractal structure toward stepped sheet-like structure. A denim-like graphene nanosheet (DGNS) has been fabricated by annealing the F127-coated stepped sheet-like scaffold in nitrogen.

Tailoring Highly N-Doped Carbon Materials from Hexamine-Based MOFs: Superior Performance and New Insight into the Roles of N Configurations in Na-Ion Storage.

To prepare highly N-doped carbon materials (HNCs) as well as to determine the influence of N dopants on Na-ion storage performance, hexamine-based metal-organic frameworks are employed as new and efficient precursors in the preparation of HNCs. The HNCs possess reversible capacities as high as 160 and 142 mA h g at 2 A g (≈8 C) and 5 A g (≈20 C), respectively, and maintain values of 145 and 123 mA h g after 500 cycles, thus exhibiting excellent rate and long-term cyclic performance. Based on systematic analysis, a new insight into the roles of the different N configurations in Na-ion storage is proposed.

MOF-derived multifractal porous carbon with ultrahigh lithium-ion storage performance.

Porous carbon is one of the most promising alternatives to traditional graphite materials in lithium-ion batteries. This is not only attributed to its advantages of good safety, stability and electrical conductivity, which are held by all the carbon-based electrodes, but also especially ascribed to its relatively high capacity and excellent cycle stability. Here we report the design and synthesis of a highly porous pure carbon material with multifractal structures.

Amorphous FeO/Graphene Composite Nanosheets with Enhanced Electrochemical Performance for Sodium-Ion Battery.

With the increasing use of sodium-ion batteries (SIBs), developing cost-effective anode materials, such as metal oxide, for Na-ion storage is one of the most attractive topics. Due to the obviously larger ion radius of Na than that of Li, most metal oxide electrode materials fail to exhibit the same high performance for SIBs like that of Li-ion batteries. Herein, iron oxide was employed to demonstrate a concept that rationally designing an amorphous structure should be useful to enhance Na-ion storage performance of a metal oxide.

Two dimensional layered Co0.85Se nanosheets as a high-capacity anode for lithium-ion batteries.

In recent years, two-dimensional (2D) layered transitional metal chalcogenides (TMCs) have received much attention as promising electrode materials in energy storage. Although recent reports on 2D TMC nanostructures have demonstrated promising electrochemical performances, the major scientific challenge is to develop a viable synthesis process to produce layered structures of chalcogenides (Co, Ni or Fe based TMCs) as anode materials. In this work, we propose the synthesis of layered Co0.

Graphene quantum dots as the electrolyte for solid state supercapacitors.

We propose that graphene quantum dots (GQDs) with a sufficient number of acidic oxygen-bearing functional groups such as -COOH and -OH can serve as solution- and solid- type electrolytes for supercapacitors. Moreover, we found that the ionic conductivity and ion-donating ability of the GQDs could be markedly improved by simply neutralizing their acidic functional groups by using KOH. These neutralized GQDs as the solution- or solid-type electrolytes greatly enhanced the capacitive performance and rate capability of the supercapacitors.

Lithiation Confined in One Dimensional Nanospace of TiO2 (Anatase) Nanotube to Enhance the Lithium Storage Property of CuO Nanowires.

We have fabricated CuO@TiO2 nanocable arrays by a facile method involving in situ thermal oxidation of Cu foil and coating of tetrabutyl titanate solution. The structure of the nanocables has been investigated by various techniques to comfirm that the cores are mainly crystalline monoclinic CuO, and the shells are crystalline tetragonal anatase TiO2. When used as an anode material for lithium-ion batteries, the nanoconfinement effect plays an important role in improving the lithium-ion storage preformance: the lithiation will be confined in one-dimensional space of TiO2 nanotubes to limit the pulverization of CuO, and the phase interface will cause an interfacial adsorption to enrich more lithium ions at some level.

Phenolic resin-grafted reduced graphene oxide as a highly stable anode material for lithium ion batteries.

A novel and effective route for preparing phenol formaldehyde resin grafted reduced graphene oxide (rGO-g-PF) electrode materials with highly enhanced electrochemical properties is reported. In order to prepare rGO-g-PF, hydroxymethyl-terminated PF is initially grafted to graphene oxide (GO) via esterification reaction. Subsequently, the grafted GO is reduced by the carbonization process under an inert gas atmosphere.

Carbon-nanotube-encapsulated FeF₂ nanorods for high-performance lithium-ion cathode materials.

Application of iron fluoride, a promising candidate of cathode materials for lithium ion batteries, is being hindered by its poor electrochemical performance caused by low electronic conductivity and large volume change. Design of carbon-encapsulated transitional metal compounds (including fluoride, oxide, sulfide, etc.) structure is one of the most effective strategies in improving their lithium-ion storage performance.