High Anodic Performance of Co 1,3,5-Benzenetricarboxylate Coordination Polymers for Li-Ion Battery

The influence of crystal facet on the catalytic performance of MOFs-derived NiO with different morphologies for the total oxidation of propane: The defect engineering dominated by solvent regulation effect

Crystal facet and defect engineering are crucial for designing heterogeneous catalysts. In this study, different solvents were utilized to generate NiO with distinct shapes (hexagonal layers, rods, and spheres) using nickel-based metal-organic frameworks (MOFs) as precursors. It was shown that the exposed crystal facets of NiO with different morphologies differed from each other. Various characterization techniques and density functional theory (DFT) calculations revealed that hexagonal-layered NiO (NiO-L) possessed excellent low-temperature reducibility and oxygen migration ability. The (111) crystal plane of NiO-L contained more lattice defects and oxygen vacancies, resulting in enhanced propane oxidation due to its highest O2 adsorption energy. Furthermore, the higher the surface active oxygen species and surface oxygen vacancy concentrations, the lower the C-H activation energy of the NiO catalyst and hence the better the catalytic activity for the oxidation of propane. Consequently, NiO-L exhibited remarkable catalytic activity and good stability for propane oxidation. This study provided a simple strategy for controlling NiO crystal facets, and demonstrated that the oxygen defects could be more easily formed on NiO(111) facets, thus would be beneficial for the activation of C-H bonds in propane. In addition, the results of this work can be extended to the other fields, such as propane oxidation to propene, fuel cells, and photocatalysis.

3D flower-like bimetallic Ni-Co metal-organic framework as an electrocatalyst for the oxygen evolution reaction

The rational design and facile preparation of a catalyst with high activity, strong durability and low consumption for the oxygen evolution reaction (OER) is an ongoing challenge in water splitting to generate clean and renewable H2 fuel. Herein, bimetallic metal-organic frameworks (MOFs) with a uniform morphology, controlled metal ratio and low crystallinity were constructed using a simple and reliable one-step solvothermal method. The three-dimensional (3D) flower-like MOF (F-Ni1Co4-BTC) with a Ni to Co molar ratio of 1 : 4 coordinated with 1,3,5-benzenetricarboxylic acid exhibited excellent OER catalytic activity compared with its corresponding counterparts, which can be attributed to the establishment of the exquisite morphology, the proportion of the dual-metal center, and the formation of active intermediates. Furthermore, when F-Ni1Co4-BTC was directly grown on carbon cloth (F-Ni1Co4-BTC/CC), it achieved an obvious improvement in electrochemical performance, affording a low overpotential of 292 mV at a current density of 10 mA cm-2, a small Tafel slope (48 mV dec-1), and excellent mechanical durability in an alkaline electrolyte, which is due to the integrated electrode attained richer active sites and faster electron transfer rate with the introduction of highly conductive carbon cloth. Our work offers a promising strategy to tailor the properties of bimetallic MOFs and the possibility of highly efficient earth-abundant catalysts for practical applications.

In Situ Flash Synthesis of Ultra-High-Performance Metal Oxide Anode through Shunting Current-Based Electrothermal Shock

The synthesis of anode materials plays an important role in determining the production efficiency, cost, and performance of lithium-ion batteries (LIBs). However, a low-cost, high-speed, scalable manufacturing process of the anode with the desired structural feature for practical technology adoption remains elusive. In this study, we propose a novel method called in situ flash shunt-electrothermal shock (SETS) which is controllable, fast, and energy-saving for synthesizing metal oxide-based materials. By using the example of direct electrothermal decomposition of ZIF-67 precursor loaded onto copper foil support, we achieve rapid (0.1-0.3 s) pyrolysis and generate porous hollow cubic structure material consisting of carbon-coated ultrasmall (10-15 nm) subcrystalline CoO/Co nanoparticles with controllable morphology. It was shown that CoO/Co@N-C exhibits prominent electrochemical performance with a high reversible capacity up to 1503.7 mA h g-1 after 150 cycles at 0.2 A g-1and stable capacities up to 434.1 mA h g-1 after 400 cycles at a high current density of 6 A g-1. This fabrication technique integrates the synthesis of active materials and the formation of electrode sheets into one process, thus simplifying the preparation of electrodes. Due to the simplicity and scalability of this process, it can be envisaged to apply it to the synthesis of metal oxide-based materials and to achieve large-scale production in a nanomanufacturing process.

Formulation and mechanism of copper tartrate - a novel anode material for lithium-ion batteries

Batteries play an increasingly critical role in the functioning of contemporary society. To ensure future proofing of battery technology, new materials and methods that overcome the current shortcomings need to be developed. Here we report the use of the inexpensive and off the shelf metal-carboxylate, copper tartrate, as a high-capacity anode material for lithium-ion batteries, providing a specific capacity of 744 mA h g-1 when cycled at 50 mA g-1. Additionally, an unusual capacity gain with cycling is investigated using advanced techniques including X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), and small and ultra-small angle neutron scattering (SANS and USANS), providing insight into the structure-performance relationship of the electrode. Subsequently, a novel method of in situ generation of the active material is demonstrated using the reaction between the parent acid, tartaric acid, and the copper current collector during electrode formulation. This serves to increase and stabilise the electrode performance, as well as to make use of a cheaper feedstock (tartaric acid), and reduce some of the "dead mass" of the copper current collector.

Confined Bismuth-Organic Framework Anode for High-Energy Potassium-Ion Batteries

Metal-organic frameworks (MOFs) with inherent porosity, controllable structures, and designable components are recognized as attractive platforms for designing advanced electrodes of high-performance potassium-ion batteries (PIBs). However, the poor electrical conductivity and low theoretical capacity of many MOFs lead to inferior electrochemical performance. Herein, for the first time, a confined bismuth-organic framework with 3D porous matrix structure (Bi-MOF) as anode for PIBs via a facile wet-chemical approach is reported. Such a porous structure design with double active centers can simultaneously ensure the structure integrity and efficient charge transport to enable high-capacity electrode with super cycling life. As a result, the Bi-MOF for PIBs exhibits high reversible capacity (419 mAh g^-1 at 0.1 A g^-1 ), outstanding cycling stability (315 mAh g^-1 at 0.5 A g^-1 after 1200 cycles), and excellent full battery performance (a high energy density of 183 Wh kg^-1 is achieved, outperforming all reported metal-based anodes for PIBs). Moreover, the K⁺ storage mechanisms of the Bi-MOF are further unveiled by in situ Raman, ex situ high-resolution transmission electron microscopy, and ex situ Fourier-transform infrared spectroscopy. This ingenious electrode design may provide further guidance for the application of MOF in energy storage systems.

Nanomaterial with Core-Shell Structure Composed of {P2W18O62} and Cobalt Homobenzotrizoate for Supercapacitors and H2O2-Sensing Applications

Designing and preparing dual-functional Dawson-type polyoxometalate-based metal-organic framework (POMOF) energy storage materials is challenging. Here, the Dawson-type POMOF nanomaterial with the molecular formula CoK₄[P₂W₁₈O₆₂]@Co₃(btc)₂ (abbreviated as {P₂W₁₈}@Co-BTC, H₃btc = 1,3,5-benzylcarboxylic acid) was prepared using a solid-phase grinding method. XRD, SEM, TEM et al. analyses prove that this nanomaterial has a core-shell structure of Co-BTC wrapping around the {P₂W₁₈}. In the three-electrode system, it was found that {P₂W₁₈}@Co-BTC has the best supercapacitance performance, with a specific capacitance of 490.7 F g^-1 (1 A g^-1) and good stability, compared to nanomaterials synthesized with different feedstock ratios and two precursors. In the symmetrical double-electrode system, both the power density (800.00 W kg^-1) and the energy density (11.36 Wh kg^-1) are greater. In addition, as the electrode material for the H₂O₂ sensor, {P₂W₁₈}@Co-BTC also exhibits a better H₂O₂-sensing performance, such as a wide linear range (1.9 μM-1.67 mM), low detection limit (0.633 μM), high selectivity, stability (92.4%) and high recovery for the detection of H₂O₂ in human serum samples. This study provides a new strategy for the development of Dawson-type POMOF nanomaterial compounds.

Graphite-like structured conductive polymer anodes for high-capacity lithium storage with optimized voltage platform

Graphite is a widely used anode material in commercial lithium-ion batteries (LIBs), but its low theoretical specific capacity and extremely low redox potential limit its application in high-performance lithium-ion batteries. However, developing lithium-ion battery anode with high specific capacity and suitable working potential is still challenging. At present, conductive polymers with excellent properties and graphite-like structures are widely used in the field of electrochemistry, but their Li⁺ storage mechanism and kinetics are still unclear and need to be further investigated. Therefore, we synthesized the conducting polymer Fe₃(2, 3, 6, 7, 10, 11-hexahydroxytriphenylene)₂ (Fe-CAT) by the liquid phase method, in which the d-π conjugated structure and pores facilitate electron transfer and electrolyte infiltration, improving the comprehensive electrochemical performance. The Fe-CAT electrode displays a high capacity of 950 mA h g^-1 at 200 mA g^-1. At the current density of 5.0 A g^-1, the electrode shows a reversible capacity of 322 mA h g^-1 after 1000 cycles. The average lithiation voltage plateau is ∼ 0.79 V. The combination of ex-situ characterization techniques and electrochemical kinetic analysis reveals the source of the excellent electrochemical performance of Fe-CAT. During the charging/discharging process, the aromatic ring in the organic ligand is involved in the redox reaction. Such results will provide new insights for the design of next-generation high-performance electrode materials for LIBs.

In Situ Formation of o-Phenylenediamine Cascade Polymers Mediated by Metal-Organic Framework Nanozymes for Fluorescent and Photothermal Dual-Mode Assay of Acetylcholinesterase Activity

A fluorescent and photothermal dual-mode assay method was established for the detection of acetylcholinesterase (AChE) activity based on in situ formation of o-phenylenediamine (oPD) cascade polymers. First, copper metal-organic frameworks of benzenetricarboxylic acid (Cu-BTC) were screened out as nanozymes with excellent oxidase-like activity and confinement catalysis effect. Then, an ingenious oPD cascade polymerization strategy was proposed. That is, oPD was oxidized by Cu-BTC to oPD oligomers with strong yellow fluorescence, and oPD oligomers were further catalyzed to generate J-aggregation, which promotes the formation of oPD polymer nanoparticles with a high photothermal effect. By utilizing thiocholine (enzymolysis product of acetylthiocholine) to inhibit the Cu-BTC catalytic effect, AChE activity was detected through the fluorescence-photothermal dual-signal change of oPD oligomers and polymer nanoparticles. Both assay modes have low detection limitation (0.03 U L^-1 for fluorescence and 0.05 U L^-1 for photothermal) and can accurately detect the AChE activity of human serum (recovery 85.0-111.3%). The detection results of real serum samples by fluorescent and photothermal dual modes are consistent with each other (relative error ≤ 5.2%). It is worth emphasizing that this is the first time to report the high photothermal effect of oPD polymers and the fluorescence-photothermal dual-mode assay of enzyme activity.

Efficient Metal-Oriented Electrodeposition of a Co-Based Metal-Organic Framework with Superior Capacitive Performance

An efficient cathodic electrodeposition method is developed for coating Co-based metal-organic frameworks (Co-MOF) on carbon fiber cloth (CFC), a widely used substrate in energy fields. The use of a highly active Co metal surface enables nucleation and growth of Co-MOF in 3D rodlike crystal bundles. When used as a binder-free electrode (Co-MOF/CFC) for supercapacitors, it shows a high areal capacitance of 1784 mF cm^-2 at 1 mA cm^-2 , good cycling stability and excellent rate capability. The assembled asymmetric all-solid-state supercapacitor device (Co-MOF/CFC//AC) delivers a high energy density and power density. This work may open up an effective approach to realize the electrosynthesis of MOF films, promoting use in energy storage and conversion fields.

Metal-organic framework (MOF) composites as promising materials for energy storage applications

Metal-organic framework (MOF) composites are considered to be one of the most vital energy storage materials due to their advantages of high porousness, multifunction, various structures and controllable chemical compositions, which provide a great possibility to find suitable electrode materials for batteries and supercapacitors. However, MOF composites are still in the face of various challenges and difficulties that hinder their practical application. In this review, we introduce and summarize the applications of MOF composites in batteries, covering metal-ion batteries, lithium-sulfur batteries, lithium-oxygen batteries and zinc-air batteries, as well as supercapacitors. In addition, the application challenges of MOF composites in batteries and supercapacitors are also summarized. Finally, the basic ideas and directions for further development of these two types of electrochemical energy storage devices are proposed.

Hierarchical multi-yolk-shell copper oxide@copper-1, 3, 5-benzenetricarboxylate as an ultrastable anode for lithium ion batteries

The capacity attenuation of transition metal oxides (TMOs) and metal-organic frameworks (MOFs) is the obstacle for practical application in lithium ion batteries, due to the extensive volume variation upon charge/discharge cycles. Herein, a hierarchical composite material with copper oxide (CuO) multi-yolks and copper-1, 3, 5-benzenetricarboxylate (Cu-BTC) shell is synthesized by a facile method to study the effect of the hierarchical structure on the electrochemical performance. The porosity and pore volume of CuO@Cu-BTC composites are optimized to buffer the volume change and facilitate the infiltration of electrolytes by altering reaction conditions. The CuO@Cu-BTC (20 h) with the largest surface area and pore volume delivers an excellent reversible capacity of 780.7 mAh g^-1 at 200 mA g^-1 after 100 cycles, and ultrastable long-term performance with a specific capacity of 569 mAh g^-1 at a current density of 1000 mA g^-1 after 900 cycles. The corresponding full battery shows moderate capacity retention from 149.4 to 125.8 mAh g^-1 after 70 cycles, with a specific capacity retention of 84.2%, based on the mass of lithium iron phosphate (LiFePO₄) at 0.2 C (1 C = 170 mA g^-1). This strategy applies copper oxide as the metal source of the coordination compound, as well as the internal yolks, which can be extended to the in-situ construction of other hierarchical composites, providing a new avenue for practical application of TMOs and MOFs as anode materials.

Fe-Based metal–organic frameworks as functional materials for battery applications

This review presents a comprehensive discussion on the development and application of pristine Fe-MOFs in lithium-ion batteries, sodium-ion batteries, potassium-ion batteries, metal–air batteries and lithium–sulfur batteries.

Gas–solid two-phase flow method for preparing trimesic acid series MOFs for catalytic thermal decomposition of ammonium perchlorate

The Zn–BTC, Co–BTC and Zn–Co–BTC series MOFs were prepared by using the GSF device and applied in the catalytic thermal decomposition of AP to change the high-temperature thermal decomposition peak of AP.

Assembling organic-inorganic building blocks for high-capacity electrode design

Metal-organic electrode materials have exhibited extraordinary promise for green and sustainable electrochemical energy storage devices, but usually suffer from low specific capacity, and poor cycling stability and rate capability because of limited active sites at organic functional groups. To address this issue, activating transition metals and carbon conjugate rings has become significantly effective to make transferred electrons dispersed in the whole molecule. In this work, we demonstrate that assembling inorganic-organic building blocks into "local" composite metal-organic materials could synergistically activate transition metal ions and carbon conjugate rings to operate cationic and anionic redox, respectively. Based on first-principles calculations, the composite inorganic-organic material FeF₃(4,4'-bpy) generates 8-electron transfer redox processes of Fe³⁺ + 2e^-→ Fe⁺ and 2 -C[double bond, length as m-dash]N- + 2e^-→ 2 (-C-N-)^- and 4 -C[double bond, length as m-dash]C- + 4e^-→ 4 (-C-C-)^-, achieving a high specific capacity of 796.7 mA h g^-1, maintaining structural stability, and reducing the band gap. The strongly electronegative F-ions in inorganic structure [FeF₄]^2- play an important role in making highly oxidized Fe³⁺ through forming a strong ligand field and electrochemically activating -C[double bond, length as m-dash]C-via electrostatic interaction with Li⁺. In addition, electrochemical measurements also reveal that the central metal Fe, and -C[double bond, length as m-dash]C and -C[double bond, length as m-dash]N bonds of the FeF₃(4,4'-bpy) electrode are the active sites for Li-ion storage to deliver a high reversible capacity (793.1 mA h g^-1 at 50 mA g^-1) and excellent rate capability, which are echoes of the DFT calculations. Through this design principle, we found a series of high-capacity metal organic electrode materials such as MnF₃(4,4'-bpy) (799.6 mA h g^-1) and VF₃(4,4'-bpy) (811.7 mA h g^-1).

2D conductive MOFs with sufficient redox sites: reduced graphene oxide/Cu-benzenehexathiolate composites as high capacity anode materials for lithium-ion batteries

As a superconductive metal-organic framework (MOF) material, Cu-BHT (BHT: benzenehexathiol) can exhibit outstanding electrochemical properties owing to the potential redox reactions of the cuprous ions, sulfur species and benzene rings of Cu-BHT, but its compact texture limits the specific capacity of Cu-BHT. To improve the dense feature of Cu-BHT, rGO/Cu-BHT (rGO: reduced graphene oxide) composite materials are fabricated via a facile route and they exhibit applicable conductivities, improved lithium ion diffusion kinetics compared to pristine Cu-BHT, and sufficient redox sites. The rGO/Cu-BHT composite materials maximize the potential capacity of Cu-BHT, and the rGO/Cu-BHT 1 : 1 material achieves outstanding reversible specific capacities of 1190.4, 1230.8, 1131.4, and 898.7 mA h g-1, at current densities of 100, 200, 500, and 1000 mA g-1, respectively, superior to those of pristine Cu-BHT and rGO. These results present the promising future of 2D conductive MOFs as functional materials for energy storage, based on the regulation of electronic conductivity, redox sites, and lithium ion diffusion kinetics.

Stepwise collapse of a giant pore metal-organic framework

Defect engineering is a powerful tool that can be used to tailor the properties of metal-organic frameworks (MOFs). Here, we incorporate defects through ball milling to systematically vary the porosity of the giant pore MOF, MIL-100 (Fe). We show that milling leads to the breaking of metal-linker bonds, generating additional coordinatively unsaturated metal sites, and ultimately causes amorphisation. Pair distribution function analysis shows the hierarchical local structure is partially retained, even in the amorphised material. We find that solvents can be used to stabilise the MIL-100 (Fe) framework against collapse, which leads to a substantial retention of porosity over the non-stabilised material.

A novel crystalline nanoporous iron phosphonate based metal–organic framework as an efficient anode material for lithium ion batteries

A new Fe-MOF prepared by using a tetraphosphonic acid as a ligand is reported and it showed high specific capacity and excellent recycling efficiency in lithium-ion batteries.

Cobalt-based metal–organic frameworks as functional materials for battery applications

Research progress on cobalt-based metal–organic frameworks as functional materials for battery applications has been presented.

Recent Developments of Nanomaterials and Nanostructures for High-Rate Lithium Ion Batteries

Lithium ion batteries have been considered as a promising energy-storage solution, the performance of which depends on the electrochemical properties of each component, including cathode, anode, electrolyte and separator. Currently, fast charging is becoming an attractive research field due to the widespread application of batteries in electric vehicles, which are designated to replace conventional diesel automobiles in the future. In these batteries, rate capability, which is closely linked to the topology and morphology of electrode materials, is one of the determining parameters of interest. It has been revealed that nanotechnology is an exceptional tool in designing and preparing cathodes and anodes with outstanding electrochemical kinetics due to the well-known nanosizing effect. Nevertheless, the negative effects of applying nanomaterials in electrodes sometimes outweigh the benefits. To better understand the exact function of nanostructures in solid-state electrodes, herein, a comprehensive review is provided beginning with the fundamental theory of lithium ion transport in solids, which is then followed by a detailed analysis of several major factors affecting the migration of lithium ions in solid-state electrodes. The latest developments in characterisation techniques, based on either electrochemical or radiology methodologies, are covered as well. In addition, state-of-the-art research findings are provided to illustrate the effect of nanomaterials and nanostructures in promoting the rate performance of lithium ion batteries. Finally, several challenges and shortcomings of applying nanotechnology in fabricating high-rate lithium ion batteries are summarised.

Electrochemically Active In Situ Crystalline Lithium-Organic Thin Films by ALD/MLD

Intercalated metal-organic framework (iMOF) type electrochemically active aromatic metal carboxylates are intriguing material candidates for various energy storage devices and microelectronics. In this work, we grow in situ crystalline thin films of such materials through atomic/molecular layer deposition (ALD/MLD); the remarkable benefit of this approach is the possibility to evaluate their electrochemical properties in a simple cell configuration without any additives. Five organic linkers are investigated in combination with lithium: terephthalic acid (TPA), 3,5-pyridinedicarboxylic acid (PDC), 2,6-naphthalenedicarboxylic acid (NDC), 4,4'-biphenyldicarboxylic acid (BPDC), and 4,4'-azobenzenedicarboxylic acid (AZO). In particular, the electrochemical activity of Li-PDC and the crystal structure of Li-AZO are addressed here for the first time. We believe that the in situ gas-phase thin-film deposition is a crucial requirement to benefit from the iMOF-type electrode materials in, e.g., microelectronics and wearable devices.

General Construction of 2D Ordered Mesoporous Iron-Based Metal-Organic Nanomeshes

Nanomeshes with highly regular, permeable pores in plane, combining the exceptional porous architectures with intrinsic properties of 2D materials, have attracted increasing attention in recent years. Herein, a series of 2D ultrathin metal-organic nanomeshes with ordered mesopores is obtained by a self-assembly method, including metal phosphate and metal phosphonate. The resultant mesoporous ferric phytate nanomeshes feature unique 2D ultrathin monolayer morphologies (≈9 nm thickness), hexagonally ordered, permeable mesopores of ≈16 nm, as well as improved surface area and pore volume. Notably, the obtained ferric phytate nanomeshes can directly in situ convert into mesoporous sulfur-doped metal phosphonate nanomeshes by serving as an unprecedented reactive self-template. Furthermore, as advanced anode materials for Li-ion batteries, they deliver excellent capacity, good rate capability, and cycling performance, greatly exceeding the similar metal phosphate-based materials reported previously, resulting from their unique 2D ultrathin mesoporous structure. Therefore, the work will pave an avenue for constructing the other 2D ordered mesoporous materials, and thus offer new opportunities for them in diverse areas.

Structure and electrochemical properties of hierarchically porous carbon nanomaterials derived from hybrid ZIF-8/ZIF-67 bi-MOF coated cyclomatrix poly(organophosphazene) nanospheres

Hierarchically porous carbon nanostructures with intrinsically doped heteroatoms and metal elements are attractive for electrochemical energy storage applications.

A green ligand-based copper–organic framework: a high-capacity lithium storage material and insight into its abnormal capacity-increase behavior

The abnormal capacity-increase behavior of high-Li-storage-performance Cu-CIT MOF is investigated by EPR and XAFS, which is found to be induced by gradual redox participation of metal centers during cycles.

Coordination compounds in lithium storage and lithium-ion transport

The application of coordination compounds for lithium storage and lithium-ion transport.

Synthesis of micro/nanoscaled metal–organic frameworks and their direct electrochemical applications

Developing strategies to control the morphology and size of MOFs is important for their applications in batteries, supercapacitors and electrocatalysis. This review focuses on the design and fabrication of MOFs at the micro/nanoscale.

Bottom-Up Fabrication of 1D Cu-based Conductive Metal-Organic Framework Nanowires as a High-Rate Anode towards Efficient Lithium Storage

Conductive metal-organic frameworks (MOFs), as a newly emerging multifunctional material, hold enormous promise in electrochemical energy-storage systems owing to their merits including good electronic conductivity, large surface area, appropriate pore structure, and environmental friendliness. In this contribution, a scalable solvothermal strategy was devised for the bottom-up fabrication of 1D Cu-based conductive MOF, that is, Cu₃ (2,3,6,7,10,11-hexahydroxytriphenylene)₂ (Cu-CAT) nanowires (NWs), which were further utilized as a competitive anode for lithium-ion batteries (LIBs). The intrinsic Li storage mechanism of the Cu-CAT electrode was also explored. Benefiting from its structural virtues, the resultant 1D Cu-CAT NWs were endowed with superb Li⁺ diffusion coefficients and electrochemical conductivities and exhibited remarkably high-rate reversible capacities of approximately 631 mAh g^-1 at 0.2 A g^-1 and even approximately 381 mAh g^-1 at 2 A g^-1 , along with striking capacity retention of 81 % after 500 cycles at 0.5 A g^-1 . In addition, a Cu-CAT NWs-based full cell assembled with LiNi_0.8 Co_0.1 Mn_0.1 O₂ as the cathode displayed a large energy density of approximately 275 Wh kg^-1 as well as excellent cycling behavior. These results manifest the promising application of 1D conductive Cu-CAT NWs in advanced LIBs and even other potential versatile energy-related fields.

MOF-Derived CuS@Cu-BTC Composites as High-Performance Anodes for Lithium-Ion Batteries

The CuS(x wt%)@Cu-BTC (BTC = 1,3,5-benzenetricarboxylate; x = 3, 10, 33, 58, 70, 99.9) materials are synthesized by a facile sulfidation reaction. The composites are composed of octahedral Cu₃ (BTC)₂ ·(H₂ O)₃ (Cu-BTC) with a large specific surface area and CuS with a high conductivity. The as-prepared CuS@Cu-BTC products are first applied as the anodes of lithium-ion batteries (LIBs). The synergistic effect between Cu-BTC and CuS components can not only accommodate the volume change and stress relaxation of electrodes but also facilitate the fast transport of Li ions. Thus, it can greatly suppress the transformation process from Li₂ S to polysulfides by improving the reversibility of the conversion reaction. Benefiting from the unique structural features, the optimal CuS(70 wt%)@Cu-BTC sample exhibits a remarkably improved electrochemical performance, showing an over-theoretical capacity up to 1609 mAh g^-1 after 200 cycles (100 mA g^-1 ) with an excellent rate-capability of ≈490 mAh g^-1 at 1000 mA g^-1 . The outstanding LIB properties indicate that the CuS(70 wt%)@Cu-BTC sample is a highly desirable electrode material candidate for high-performance LIBs.