Bimetallic Metal-Organic Framework with High-Adsorption Capacity toward Lithium Polysulfides for Lithium–sulfur Batteries

The practical application of Li-S batteries is largely impeded by the“shuttle effect”generated at the cathode which results in a short life cycle of the battery.To address this issue,this work discloses a bimetallic metal-organic framework(MOF)as a sulfur host material based on Al-MOF,commonly called(Al)MIL-53.To obtain a high-adsorption capacity to lithium polysulfides(Li_(2)S_(x),4≤x≤8),we present an effective strategy to incorporate sulfiphilic metal ion(Cu^(2+))with high-binding energy to Li_(2)S_(x) into the framework.Through a one-step hydrothermal method,Cu^(2+) is homogeneously dispersed in Al-MOF,producing a bimetallic Al/Cu-MOF as advanced cathode material.The macroscopic Li2S4 solution permeation test indicates that the Al/Cu-MOF has better adsorption capacity to lithium polysulfides than monometallic Al-MOF.The sulfur-transfusing process is executed via a melt-diffusion method to obtain the sulfur-containing Al/CuMOF(Al/Cu-MOF-S).The assembled Li-S batteries with Al/Cu-MOF-S yield improved cyclic performance,much better than that of monometallic AlMOF as sulfur host.It is shown that chemical immobilization is an effective method for polysulfide adsorption than physical confinement and the bimetallic Al/Cu-MOF,formed by incorporation of sulfiphilic Cu^(2+) into porous MOF,will provide a novel and powerful approach for efficient sulfur host materials.

金属有机框架集成到打印器件的最新进展及其应用

金属有机框架(metal-organic frameworks,MOFs)凭借具有吸引力的特性在科学研究中取得了前所未有的进展.然而,MOFs的缺点如加工性差、化学稳定性低和机械性能有限阻碍了它们的广泛应用.具有几何可控性、快速原型制作和可持续制造等优势的打印技术可以有效解决MOFs的这些问题.截至目前,MOF集成的打印器件已经取得了重要的突破和进步.本文提供了MOF集成的印刷设备的最新进展.首先总结了基于MOF器件制造常用的印刷技术.然后,重点介绍了打印技术在器件制造方面以及所制造的器件在具体应用方面所取得的重要进展.最后,提出了这些器件潜在的研究前沿和目前面临的主要挑战.

Construction of hierarchical nanostructures and NiO nanosheets@nanorods for efficient urea electrooxidation

Hierarchical NiO nanosheets@nanorods have been rationally designed and constructed for efficient urea electrooxidation in an alkaline solution. The critical synthetic strategy, engaging the one-step anioncompetitive reaction, precisely integrates two nickel-based materials into a heterostructure with Ni(OH)_(2) nanosheets and NiC_(2)O_(4) nanorods. Benefiting from the hierarchically porous structure and high specific surface area, the NiO NNs can improve the escape efficiency of gas in electrochemical reactions and maintain sustainability. Furthermore, this distinctive structure can expose highly dispersed active sites for enhancing urea molecules' adsorption, surface-dependent redox reactions, and electrical conductivities. As a result, these hierarchical NiO nanosheets@nanorods exhibit superior activity with a low overpotential of 156 mV at 10 mA/cm^(2), and a slight Tafel slope of 40.7 m V/dec, and high stability with almost no decay of 12,000 s for urea electrooxidation. This work promotes the application of well-designed hierarchical structure in electrooxidizing urea and provides a possibility for highly efficient electrolysis of alkaline urea wastewater.

Rational design of Prussian blue analogue-derived manganese-iron oxides-based hybrids as high-performance Li-ion-battery anodes

The unique components and architecture of Prussian blue analogous(PBAs) offer great potential for the construction of various functional nanostructures. Herein, we reported the preparation of a series of Mn–Fe oxides-based hybrids using Mn–Fe PBA as a template and an organic carbon source by calcination.The study focuses on revealing the interaction between the microstructure and electrochemical performance of the products obtained at different calcination temperatures. Notably, the as-derived porous Fe–Fe0.33Mn0.67O/C nanocubes(i.e., M600) exhibited the best rate capability and cycle life compared with other samples(~890 m Ah/g at 0.1 A/g, 626.8 m Ah/g after 1000 cycles at 1.0 A/g with a 99% capacity retention). These can be attributed to the fact that the porous structure provides shorter Li+diffusion path and promotes the penetration of electrolyte. Besides, the N-doped C formed by the carbonization of organic ligands can buffer the volume change and prevent the aggregation of Fe_(0.33)Mn_(0.67)O nanoparticles during the discharge/charge cycles. Moreover, the presence of metallic Fe enhances the conductivity and the electrochemical activity, which accelerates the electrochemical reactions. Therefore, reasonable design of microstructure and compositions of functional nanocomposites is the key to obtain ideal electrochemical properties.

Rational design of self-sacrificial template derived quasi-Cu-MOF composite as anodes for high-performance lithium-ion batteries

MOF-based composites have aroused widespread concern due to their controllable morphology and pore characteristics.Nevertheless,the poor conductivity and volume expansion hinder its practical application in LIBs.Herein a classical structure HKUST-1,as the precursor,was used to fabricate quasi-Cu-MOF composite through a facile thermal decomposition strategy.The results showed that quasi-Cu-MOF composite had superior reversible specific capacity(627.5 m Ah/g at 100 m A/g)and outstanding cycle stability(514.6 m Ah/g at 500 m A/g after 400 cycles)as anodes for LIBs.The results demonstrated that the lowtemperature calcination strategy played a significant role in morphology retaining during cycling and the derived copper framework play a crucial part in conductivity improvement.This work is helpful to the design of high-performance electrodes with advanced three-dimensional hierarchical structures.

Three-dimensional MXene-encapsulated porous Ni-NDC nanosheets as anodes for enhanced lithium-ion batteries

Although metal–organic frameworks have been heavily tested as the anode materials for lithium-ion batteries(LIBs),the poorer conductivity,easy collapse of frameworks,and serious volume expansion limit their further application in LIBs.Herein,we report a facile approach to obtain MXene-encapsulated porous Ni-naphthalene dicarboxylic acid(Ni-NDC)nanosheets by hybridizing ultrathin Ti_(3)C_(2)MXene and three-dimensional(3D)Ni-NDC nanosheet aggregates.In the structure of Ni-NDC/MXene hybrids,the interlayer hydrogen-bond interaction between Ni-NDC and MXene can effectively increase the interlayer spacing and further inhibit the oxidation of pure MXene.Hence,the introduction of MXene(a conductive matrix)could further improve the conductivity of Ni-NDC,avoid self-agglomeration,and buffer the volume expansion of Ni-NDC nanosheets.Benefiting from the synergistic effects between Ni-NDC and MXene,Ni-NDC/MXene hybrid electrode exhibits a reversible discharge capacity(579.8 mA∙h∙g^(−1)at 100 mA∙g^(−1)after 100 cycles)and good long-term cycling performance(310 mA∙h∙g^(−1)at 1 A∙g^(−1)after 500 cycles).

SiO_x-based(0

Silicon(Si) materials as anode materials for applications in lithium-ion batteries(LIBs) have received increasing attention.Among the Si materials,the electrochemical properties of SiOx-based(0<x≤2)composites are the most prominent.However,due to the cycling stability of SiOx being far from practical,there are some problems,such as Iow initial coulombic efficiency(ICE),obvious volume expansion and poor conductivity.Researchers in various countries have optimized the electrochemical properties of SiOx-based composites by means of pore formation,surface modification,and the choice of constituents.In this review,SiOx-based composites are classified into three categories based on the valency of Si(SiO2 composites,SiO composites and SiOx(0<x<2) composites).The synthesis,morphologies and electrochemical properties of the SiOx-based composites that are applied in LIB are discussed.Finally,the prope rties of several common SiOx-based composites are briefly compared and the challenges faced by SiOx-based composites are highlight.

Watermelon-like multicore-shell Fe(PO_(3))_(2)@carbon nanocapsule anode to construct an all iron phosphate-based sodium ion battery

Rechargeable sodium ion battery(SIB)has attracted much attention recently.However,the deficiency of high-performance electrode materials limits its commercial development.Exploring new cost-effective,high safe electrode materials and full battery matching technology is an important direction of future research.In this work,a novel watermelon-like multicore-shell Fe(PO_(3))_(2)@C nanocapsule anode material is designed via a facile and eco-friendly process for high performance SIB.Fe(PO_(3))_(2)@C composite anode exhibits remarkable electrochemical performances for SIB,showing high sodium storage capacity(452 mAh·g^(-1) at 0.2 A·g^(-1)),good rate(235 mAh·g^(-1) at 10 A·g^(-1)),stable long-term cycling life(210 mAh·g^(-1) over 2,000 cycles under 5 A·g^(-1)),and superior high-low temperature performance.Furthermore,a new type all iron-based phosphate full battery with high specific capacity is constructed,which can output initial capacity of 309 mAh·g^(-1) and a high energy density of 254,107,and 82 Wh·kg^(-1) at the power density of 186,917,and 1,640 W·kg^(-1) at room temperature.The exceptional performance of multicoreshell Fe(PO_(3))_(2)@C nanocapsule structure can be ascribed to the large specific surface,good structure stability,high conductivity,as well as the multiple layer protection for superior electron/ion transportation.

Electrospun Metal–Organic Framework Nanofiber Membranes for Energy Storage and Environmental Protection

Metal–organic frameworks(MOFs)are attractive in many fields due to their unique advantages.However,the practical applications of single MOF materials are limited.In recent years,a large number of MOF-based composites have been investigated to overcome the defects of single MOF materials to broaden the avenues for the practical applications of MOFs.Among them,MOF-based hybrid nanofiber membranes fabricated by electrospinning combine the advantages of polymer nanofibers and inorganic porous materials,receiving extensive attention and development in energy storage and environmental protection.This review systematically summarizes the recent progress of MOF-based hybrid nanofiber membranes prepared by electrospinning from the perspectives of preparation and application.Firstly,two main methods for preparing MOF/polymer nanofibrous membranes are discussed.Next,the applications of MOF/polymer nanofibrous membranes in energy storage and environmental protection are summarized at length.Finally,to fully tap the potential of MOF-based nanofiber membranes in more fields,the current challenges are proposed,and future research directions are discussed.