Enhanced Lithium Storage Properties Research Articles

Synergistic effect of molybdenum dioxide wrapped nitrogen doped carbon nanotubes in binder-free anodes for enhanced lithium storage properties

Molybdenum dioxide (MoO2) is regarded as a potential anode for lithium-ion batteries due to its highly theoretical specific capacity. However, its further application in lithium-ion battery is largely limited by insufficient practical discharge capacity and cyclic performance. Here, MoO2nanoparticles are in-situ grown on three-dimensional nitrogen doped carbon nanotubes (NCNTs) on nickel foam substrate homogeneously using a simple electro-deposition method. The unique structural features are favorable for lithium ions insertion and extraction and charge transfer dynamics at electrode/electrolyte interface. As a proof of concept, the as-synthesized nanocomposites have been employed as anode for lithium-ion battery, exhibiting a reversible and significantly improved discharge capacity of ∼517 mA h g-1at the current density of 150 mA g-1as well as superior cycle and rate performance. The first-principle calculations based on density functional theory and electrochemical impedance spectroscopy results demonstrate a reduced energy barrier of lithium ions diffusion, improved lithium storage behavior, reduced structure collapse, and significantly enhanced charge transfer kinetics in MoO2/NCNTs nanocomposites with respect to MoO2powder. The excellent performance makes as-prepared MoO2/NCNTs nanocomposites promising binder-free anode for high performance lithium-ion batteries. This work also provides important theoretical insights for other state-of-the-art batteries design.

Synthesis of porous Mg2MnO4 spinel microspheres and enhanced lithium storage properties

Porous Mg2MnO4 spinel microspheres were synthesized by a facile solvothermal method. Various techniques such as X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, were used to characterize the phase composition, morphology and electronic structure of materials. The results show that Mg2MnO4 spinel material was obtained at the temperature of 600–800 °C and has a microsphere structure. The microspheres were assembled by nanoparticles, and the particle size increases with the increase of annealing temperature. Analyses of XPS spectra reveal that Mn exists in multiple valence states (+2, +3, +4) in Mg2MnO4 materials, and all the materials are mixed spinel with Mg2+ and Mn2+/3+/4+ ions occupy both tetrahedral and octahedral sites of spinel structure, and the degree of inversion decreases with increasing annealing temperature. Mg2MnO4 microspheres exhibit excellent lithium storage performance, the first discharge specific capacity of M2MO-8 is 835.3 mAh g−1 under a voltage window of 0–3 V and with a current density of 100 mA g−1, and after 100 cycles the discharge capacity of the material is as high as 406.5 mAh g−1. In addition, this material shows high cyclic reversibility. The enhanced lithium storage properties of the material can be attributed to its porous structure, which promote the transport of lithium ions and reduce the damage to the structure caused by the volume change during the charge and discharge process.

Cellulose derived fibrous vanadium-sulfide/carbon composite with enhanced lithium storage properties

Vanadium-sulfides are considered as promising anodic materials for lithium-ion batteries (LIBs) due to their unique layered structures and high theoretical capacities. However, the main challenge of vanadium-sulfide as an electrode material is still faced with slow Li-ion diffusion kinetics and inevitable structural damage during charging/discharging processes. Herein, a series of bio-inspired hierarchical fibrous VS4/C composites were designed based on cellulose substance as the scaffold and carbon source via simple hydrothermal method. The resultant fibrous VS4/C composites possessed a three-dimensional porous network structure consisting of carbon fibers coated with VS4 nanosheets. As a consequence, the optimized VS4/C anodic materials exhibit high reversible capacities (953 mAh g−1 at 0.1 A g−1), good rate features (420 mAh g−1 at 2 A g−1), and fast diffusion kinetics. The superior electrochemical properties of the VS4/C composites are mainly attributed to the three-dimensional porous network structures combined with the carbon fibers matrix, which promotes the contact between the electrode and electrolyte, alleviates the structural damage of VS4, as well as facilitates the electron transfer and Li-ion diffusion during the cycling processes.

Bimetallic Flower-like NiCoP Encapsulated in an N-Doped Carbon Shell with Enhanced Lithium Storage Properties

It continues to be a challenge to design innovative NiCoP composite anode materials to further improve rate capacity. In this work, bimetallic flower-like NiCoP encapsulated in an N-doped carbon shell (designated as NiCoP@NC) as a high-rate capable anode material for lithium-ion batteries (LIBs) was successfully designed and synthesized. The novel structure design combines the advantages of flower-like NiCoP (core) and N-doped carbon (shell). Flower-like NiCoP offers numerous interface and redox reaction sites for improving lithium storage, while the N-doped carbon shell effectively buffers volume expansion and enhances electrical conductivity. The synergistic effect between NiCoP and the N-doped carbon shell proposes a marvelous high-rate capacity (320 mA h/g even at 5 A/g) and a good cycle life with high reversible capacity (369.8 mA h/g for 700 cycles at 3 A/g with 81% retention). An investigation of kinetics performance shows that the introduction of the N-doped carbon shell enhances the charge transfer, and the pseudocapacitive behavior dominates the rapid Li+ storage of the NiCoP@NC electrode.

Facile spray-drying process for the synthesis of hollow 3D MXene-encapsulated CoSnO3 nanoboxes with enhanced lithium storage properties

Combining nanostructured materials with two-dimensional (2D) substrates has long been considered one of the most effective strategies for the production of superior-performance lithium-ion batteries (LIBs). However, the restacking of 2D materials and the volume expansion of the active material during cycling are issues that have yet to be fully addressed. Herein, we propose a facile spray-drying process to successfully encapsulate hollow CoSnO3 nanoboxes in MXene nanosheets (MX/HCTO), forming three-dimensional (3D) MXene-based microspheres as an anode for LIBs. This 3D structure effectively inhibits the restacking of MXene nanosheets, resulting in a higher surface area and a greater number of active sites for Li+ storage. Encapsulating hollow CoSnO3 nanoboxes in an MXene shell can also restrict the change in volume during cycling, thus inhibiting the structural collapse of the composite even after long-term cycling. With these advantages, the proposed 3D MX/HCTO composite exhibits a high specific capacity of 670 mA h g−1 at 5.0 A g−1 that is stable over 1000 cycles and a specific capacity of 288.6 mA h g−1 at a high current density of 20.0 A g−1. It’s easy synthesis process and inexpensive precursors also ensure that it has the potential to be scaled up for mass production.

Enhanced Lithium Storage Properties of High Sulfur Doped Hard Carbon Derived from Thiophene-Containing Conjugated Microporous Polymer

Enhanced Lithium Storage Properties of High Sulfur Doped Hard Carbon Derived from Thiophene-Containing Conjugated Microporous Polymer

One-step construction of α-MnMoO4 microstructures with enhanced lithium storage properties

Due to the synergistic effects of multiple transitional metals, high theoretical specific capacity and good electrical conductivity, α-MnMoO4 exhibits superior performance and can be utilized as one prospective lithium-ion battery anode material. Herein, a new solvothermal reduction method was adopted for the synthesis and construction of α-MnMoO4 microstructures. Both dart-like and nanosheet-based flower-like α-MnMoO4 microstructures can be prepared by tuning the initial amount of molybdenum acetylacetone during the reaction process. The electrochemical measurements show that the dart-like α-MnMoO4 microstructures and nanosheet-based flower-like α-MnMoO4 microstructures deliver the stable specific capacities of 951.4 and 861.4 mA h g−1 at a current density of 0.5 A g−1 after 400 cycles. The excellent capacity, stable and sustainable cyclic performance are much superior to the reported α-MnMoO4 particles. The improved electrochemical performance proves that α-MnMoO4 microstructures can be served as one prospective anode of lithium-ion batteries.

Integrating highly active graphite nanosheets into microspheres for enhanced lithium storage properties of silicon.

Integrating silicon (Si) and graphitic carbon into micron-sized composites by spray-drying holds great potential in developing advanced anodes for high-energy-density lithium-ion batteries (LIBs). However, common graphite particles as graphitic carbon are always too large in three-dimensional size, resulting in inhomogeneous hybridization with nanosized Si (NSi); in addition, the rate capability of graphite is poor owing to sluggish intercalation kinetics. Herein, we integrated graphite nanosheets (GNs) with NSi to prepare porous NSi-GN-C microspheres by spray-drying and subsequent calcination with the assistance of glucose. Two-dimensional GNs with average thickness of ∼80 nm demonstrate superior lithium storage capacity, high conductivity, and flexibility, which could improve the electronic transfer kinetics and structural stability. Moreover, the porous structure buffers the volume expansion of Si during the lithiation process. The obtained NSi-GN-C microspheres manifest excellent electrochemical performance, including high initial coulombic efficiency of 85.9%, excellent rate capability of 94.4% capacity retention after 50 repeated high-rate tests, and good cyclic performance for 500 cycles at 1.0 A g-1. Kinetic analysis and in situ impedance spectra reveal dominant pseudocapacitive behavior with rapid and stable Li+ insertion/extraction processes. Ex situ morphology characterization demonstrates the ultra-stable integrated structure of the NSi-GN-C. The highly active GN demonstrates great potential to improve the lithium storage properties of Si, which provides new opportunity for constructing high-performance anodes for LIBs.

Synthesis of porous Mn-based spinel microspheres with enhanced lithium storage properties

Mn-based spinel materials MgMn2O4 with porous structure were synthesized by reverse coprecipitation method at annealing temperature of 700–900 °C. The as-synthesized samples were compared with those prepared by solid-state reaction method. The phase, micro-morphology and cation distribution of spinel materials were studied by using X-ray powder diffraction, scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. The results show that the MgMn2O4 samples obtained by reverse coprecipitation method are porous microspheres, and the particle size of the samples grows with the increase of annealing temperature. The material annealed at 700 °C has the most regular morphology, and the microspheres with a diameter of about 2 µm are assembled from uniform nanoparticles (50–60 nm). X-ray photoelectron spectroscopy analysis show that all samples are mixed spinel, Mn exists in multivalent state, Mn2+ ions occupy tetrahedral sites and Mn3+ / Mn4+ ions occupy octahedral sites of spinel structure. The effects of synthesis conditions on the inversion degree (ν) of MgMn2O4 spinel were discussed. As the anode material of Li-ion batteries, the sample annealed at 700 °C shows the best electrochemical performance, and the lithium storage capacity in the first cycle is 1037.8 mAhg−1. The enhanced lithium storage properties of the anode material are due to its regular porous microsphere structure, which is conductive to contact between the electrode materials and electrolyte and improves the migration of lithium ions. In addition, the relationship between cation distribution in spinel structure and electrochemical properties was also discussed.

Vacuum quartz capsule-assisted decoration of ZIF-8 derived ZnS/PC with SnS for enhanced lithium storage properties

Owing to compositional advantages of the high theoretical capacity and 3D porous nanoarchitecture, the strategies for coupling of metal sulfide and metal-organic frameworks (MOFs) derived carbon materials have drawn considerable attention for high performance lithium storage. Herein, we present SnS decorated zeolitic imidazolate framework-8 derived ZnS/3D porous carbon composite (denoted as ZnS/PC) using the vacuum quartz capsule-assisted decoration method (denoted as ZnS/SnS/PC). In the composite, 3D-porous carbon could play the part of a conductive matrix as well as the buffer support for volume variation, while the decoration of ZnS/PC with SnS could provide abundant redox reactions, which could reinforce the storage properties and ions/electrons transfer driving force of ZnS/PC. Significantly, the synergistic coupling effect between the mixed metal sulfides and robust carbon matrix could further improve the electrochemical behavior. When compared with ZnS/PC anode for lithium-ion battery, ZnS/SnS/PC composite manifests obvious improvement in electrochemical performance for lithium storage, as well as appreciable lithium storage properties in a full lithium-ion battery.

Facile, economical, and environmental-friendly fabrication of N, P co-doped porous carbon/Sn composite with enhanced lithium storage properties

Despite the satisfactory development in preparing heteroatom-doped porous carbon/Sn composite structures, most strategies rely on complicated and multi-step template processes to tailor the porous carbon structure. Herein, a facile, economical, and environmental-friendly strategy for the one-step synthesis of N, P co-doped porous C/Sn (Sn/NPPC) composite is reported. The NPPC can relieve the large volume change and supply good electronic conductivity as well as more defects. Benefiting from the integration of these advantages, the Sn/NPPC electrode achieves superior discharge capacity (689.5 mAh/g after 100 cycles at 100 mA/g). This strategy can supply fundamental breakthroughs for reducing the synthesis cost and simplifying the synthesis complexity of heteroatom-doped porous carbon/Sn composite.

Dealloying Synthesis of Silicon Nanotubes for High‐Performance Lithium Ion Batteries

Practical applications of silicon-based anodes in lithium ion batteries have attracted unprecedented attentions due to the merits of extraordinary energy density, high safety and low cost. Nevertheless, the inevitable huge volume change upon lithiation and delithiation brings about silicon electrode integrity damage and fast capacity fading, hampering the large-scale application. Herein, a novel one-dimensional tubular silicon-nitrogen doped carbon composite (Si@NC) with a core-shell structure has been fabricated using silicon magnesium alloy and polydopamine as a template and precursor. The as-obtained composite exhibits remarkable specific capacity and ultrafast redox kinetics, an outstanding cycling stability with fine capacity of 583.6 mAh g-1 at 0.5 A g-1 over 200 cycles is delivered. Moreover, a full cell matched with LiFePO4 cathode has demonstrated a reversible capacity of 148.8 mAh g-1 with high Coulombic efficiency as well as an excellent energy density of 396 Wh kg-1 . The nanotube structure engineering and silicon confined in nitrogen doped carbon effectively alleviate the volume expansion and endow the composite with superior stability. The robust strategy developed here gives a new insight into designing silicon anodes for enhanced lithium storage properties.

Synthesis of three-dimensional honeycomb-like Fe3N@NC composites with enhanced lithium storage properties

Iron nitrides have been recognized as attractive anode candidates for lithium ion batteries (LIBs) due to their high theoretical capacities, high tap densities, cost-effectiveness, multiple electron transfer and good ionic diffusion. The strategies of pore structure engineering and carbon coating have been proven to be effective ways to address the critical issues of iron nitrides as anodes for LIBs. Herein, we synthesized a series of Fe3N@NC-x with 3D honeycomb nanostructures by a simple heating-controlled and ammoniation-assisted approach. The Fe3N@NC-x as anodes for LIBs display outstanding lithium storage properties with high reversible capacity of 767.8 mA h g−1 at 0.1 A g−1 and long-term cycling performance (814.5 mA h g−1 at 1 A g−1 over 2000 cycles). Such outstanding properties were attributed to the interconnected conductive pathways (honeycomb walls, hexagonal channels) for rapid ionic/electronic transport, the macro-/meso porous structure for the quick penetration of electrolytes and the accommodation of electrode volume variation during the cycles, meso-/micro porous structure for the additional storage of Li+, and efficient utilization of the Fe3N nanoparticles unifomly distributed through highly conductive interconnected network.

Nanoporous germanium prepared by a mechanochemical reaction with enhanced lithium storage properties.

The cost-effective and facile fabrication of nanostructured germanium for lithium-ion batteries (LIBs) remains a grand challenge. Herein, nanoporous Z-Ge was generated via a facile two-step mechanochemical-etching reaction with Mg2Ge and ZnCl2. The prepared nanoporous Ge nanoparticles, as the anode for Li-Ge half cells, showed superior LIB performance, in terms of a high capacity, good rate capability, and good long-term stability of 700 cycles. Significantly, the mechanochemical reaction was extended to produce other nanoporous Ge or Si materials such as A-Ge, Z-Si, and A-Si via the mechanochemical reaction between Mg2Ge and AlCl3, Mg2Si and ZnCl2, and Mg2Si and AlCl3.

Integrating Highly Active Graphite Nanosheet into Microspheres for Enhanced Lithium Storage Properties of Silicon

Integrating Highly Active Graphite Nanosheet into Microspheres for Enhanced Lithium Storage Properties of Silicon

Quasi-anisotropic benefits in electrospun nickel–cobalt–manganese oxide nano-octahedron as anode for lithium-ion batteries

A polyhedral Ni–Co–Mn–O nano-octahedron anode for lithium-ion batteries was synthesized, which demonstrated enhanced lithium storage properties as compared to the nanofiber counterpart.

Solid Solution Mos2-Xtex with Reduced Lattice Change Compared to Mos2-Mote2 Heterostructure for Enhanced Lithium Storage Properties

Solid Solution Mos2-Xtex with Reduced Lattice Change Compared to Mos2-Mote2 Heterostructure for Enhanced Lithium Storage Properties

Bimetallic MOFs with tunable morphology: Synthesis and enhanced lithium storage properties

A series of isostructural bimetallic metal-organic frameworks (Co–Ni-MOF) were rationally synthesized by a facile one-step solvothermal method in the presence of varying mole ratios of Co/Ni mixed-metal ions. As the Co ion doping content decreased, the morphology of Co–Ni-MOF changed from irregular nanofragments to nanospheres. Meanwhile, doping Co ions in Ni-MOF can effectively improve the Li+ storage capacity. Attributing to the combined effect of metal ion reduction and successive lithiation of the organic ligands, the improved electrical conductivity and the synergetic advantages of Co and Ni, enhanced lithium storage properties of the prepared bimetallic MOFs have been achieved. Specifically, the Co–Ni-MOF electrode with a Co/Ni molar ratio of 1:1 displays a high reversible specific capacity of 800 ​mA ​h ​g−1 with 98% specific capacity retention after 100 cycles at 100 ​mA ​g−1, as well as good rate capability (600 ​mA ​h ​g−1 ​at 500 ​mA ​g−1 and 380 ​mA ​h ​g−1 ​at 1000 ​mA ​g−1).

Retraction of the Research Article: "A universal cooperative assembly-directed method for coating of mesoporous TiO2 nano shells with enhanced lithium storage properties".

Retraction of the Research Article: "A universal cooperative assembly-directed method for coating of mesoporous TiO2 nano shells with enhanced lithium storage properties".

Design and synthesis of transition metal oxide/zeolitic imidazolate framework-67 composites

The design and synthesis of Metal-organic framework (MOF)-based composites with multiple-functionalities are highly desirable to overcome the disadvantages of pristine MOFs, such as chemical instability and poor electrical conductivity. Zeolitic imidazolate frameworks (ZIFs) are a subfamily of MOFs, and ZIF-67 is composed of Co cations and imidazole-based ligands. Herein, we propose a strategy to fabricate Transition metal oxide (TMO)/ZIF-67 composites with a rhombic dodecahedron structure, accompanied by few partially unwrapped TMOs at the edge. To some extent, the prepared composites can acquire semiconductor properties and structural stability of TMOs, as well as high specific surface area and pore characteristics of ZIF-67. Interestingly, when applied as an anode material for lithium-ion battery, the Co3O4/ZIF-67 composite showed enhanced lithium storage properties. This work provides a strategy to design and synthesize TMO/MOF composites and develop their potential applications in the field of electrochemical energy storage.