Enhanced Lithium Storage Properties Research Articles

Rational design and synthesis of yolk–shell ZnGa 2 O 4 @C nanostructure with enhanced lithium storage properties

The ability to create hybrid nanostructure with synergistic effect and confined morphology to achieve high performance and long-term stability is high desirable in lithium ion batteries. Although transition metal oxides as anode material reveal high theoretical capacities, the significant volume changes during repeated lithium insertion and extraction cause pulverization of electrode materials, resulting in rapid fade in capacity. Herein, yolk–shell nanostructure of ZnGa2O4 encapsulated by amorphous carbon is rationally designed and synthesized through two-step surface coating followed by thermal treatment and etching process. It is noteworthy that ZnGa2O4@C with yolk–shell structure is superior to pristine ZnGa2O4 and ZnGa2O4@C with core-shell structure in term of lithium storage. The stable reversible capacity of yolk–shell ZnGa2O4@C can be retained at 657.2 mAh g−1 at current density of 1 A g−1 after completion of 300 cycles, which also reveals superior rate performance. The appropriate carbon shell and void space involved in the yolk–shell structure are considered to be the crucial factor in accommodating volume expansion as well as preserving the structural integrity of yolk–shell ZnGa2O4@C.

Facile Construction of Novel 3-Dimensional Graphene/Amorphous Porous Carbon Hybrids with Enhanced Lithium Storage Properties.

Presently, porous materials have become essential to many technological applications. In this account, 3-dimensional skeleton composite materials consisting of a core-shell amorphous porous carbon/multilayer graphene are synthesized by chemical vapor deposition on Ni foam using a facile one-step growth method. The data suggest that these composites have not only outstanding electrical and mechanical properties of the multilayer graphene but also the mesoporous characteristics of the amorphous carbon. Moreover, the composited carbon materials perfectly inherit the macroporous structure of Ni foam, and the amorphous carbon core in the skeleton serves as a cushion to buffer the volume variation after the removal of Ni. The carbon composites reveal ultralow density (4.45 mg cm-3) and high conductivity (45 S cm-1), essentially issued from the perfectly preserved structural integrity of graphene. The novel carbon composites can be used as anodes for lithium ion batteries. After these carbon composites are incorporated with NaBiO3, superior electrochemical activities above 2 V can be achieved with a discharge capacity of ∼300 mAh g-1.

Ultrathin MoS2 nanosheets tightly anchoring onto nitrogen-doped graphene for enhanced lithium storage properties

Rational design of advanced electrode materials is extremely important for high-performance lithium-ion batteries (LIBs). Herein, we report a facile one-pot hydrothermal approach for formation of MoS2/nitrogen-doped graphene (MoS2/N-graphene) composite with excellent lithium storage properties as anode for LIBs. The controlled experiment results indicate that polyethyleneimine (PEI) functionalizes not only as the nitrogen source for in-situ nitrogen doping, but also as a binder for inducing and regulating the uniform growth of MoS2 nanosheets onto graphene. As a result, ultrathin MoS2 nanosheets are vertically grown onto the nitrogen-doped reduced oxide graphene (RGO), generating a distinct honeycomb-like hybrid structure. More significantly, the first principles theoretical calculations results manifest that there is a strong interaction at the interface of MoS2 and nitrogen-doped graphene, thus boosting the charge transfer. The constructing MoS2/N-graphene architecture demonstrates the improved electrochemical performances for reversible lithium storage. It shows a high reversible capacity of 1025.1mAh/g at a current density of 100mA/g and the superior rate capability, which is mainly attributed to the pseudocapacitance contributions.

Realizing high reversible capacity: 3D intertwined CNTs inherently conductive network for CuS as an anode for lithium ion batteries

CuS nanospheres interconnected by the carbon nanotubes (CNTs) have been successfully prepared via a facile one-step microwave-assisted method. The component and microstructure of CuS/CNTs hybrid materials are well characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). Assembled as electrodes and tested in lithium ion batteries, the composites show impressive electrochemical performances. After 450cycles, the CuS/0.1 CNT and CuS/0.5 CNT release more than 437 and 569mAhg−1, respectively, at 400mAg−1, which are superior to those of contrast experiments (pristine CuS and CuS mechanically mixing with CNTs). Even at the high current density of 6400mAg−1, the CuS/0.5 CNT still displays the reversible capacity of about 400mAhg−1. The improved performances can be ascribed to the inherently CNTs conducting network, boosting the interior electron transport and reaction kinetics, so that a significantly enhanced reversible capacities and rate capability can be realized. Furthermore, the surface properties and reaction kinetics of electrodes are also investigated via cyclic voltammetry (CV) and galvanostatic intermittence titration (GITT) measurements, proving the enhanced lithium storage properties.

Preparation of One-dimensional Bamboo-like Cu2-xS@C Nanorods with Enhanced Lithium Storage Properties

Nanostructure construction and surface modification are effective ways to improve the electrochemical performances of electrode materials, especially for the conversion reaction-based materials. In this study, one-dimensional carbon coating bamboo-like Cu2-xS nanorods have been delicately designed in a template-free method. The structure and morphology are well characterized via different instruments such as X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Tested in lithium batteries as the anode, the Cu2-xS@C electrode shows superior electrochemical performances to pristine Cu2-xS. At 1 and 2 C, the Cu2-xS@C nanorod electrode releases 309 and 277mAhg−1 after 300 cycles. At high rates of 15 and 22 C, the electrode still exhibits 269 and 264mAhg−1. The kinetics of electrodes are also investigated by means of cyclic voltammetry (CV) and galvanostatic intermittence titration (GITT) measurements, proving the enhanced electrochemical properties. Thus, the one-dimensional bamboo-like Cu2-xS voided nanorods can be a promising candidate for high-performance batteries.

Facial synthesis of carbon-coated ZnFe2O4/graphene and their enhanced lithium storage properties

Carbon-coated ZnFe2O4 spheres with sizes of ~110–180 nm anchored on graphene nanosheets (ZF@C/G) are successfully prepared and applied as anode materials for lithium ion batteries (LIBs). The obtained ZF@C/G presents an initial discharge capacity of 1235 mAh g−1 and maintains a reversible capacity of 775 mAh g−1 after 150 cycles at a current density of 500 mA g−1. After being tested at 2 A g−1 for 700 cycles, the capacity still retains 617 mAh g−1. The enhanced electrochemical performances can be attributed to the synergetic role of graphene and uniform carbon coating (~3–6 nm), which can inhibit the volume expansion, prevent the pulverization/aggregation upon prolonged cycling, and facilitate the electron transfer between carbon-coated ZnFe2O4 spheres. The electrochemical results suggest that the synthesized ZF@C/G nanostructures are promising electrode materials for high-performance lithium ion batteries.

3D graphene-encapsulated hierarchical urchin-like Fe3O4 porous particles with enhanced lithium storage properties

Hierarchical urchin-like Fe3O4 porous particles with 3D graphene modification (U-Fe3O4@RGO) are synthesized via cationic surfactant induced self-assembly of γ-FeOOH particles and graphene oxide (GO) sheets, followed by a calcination treatment. Fe3O4 porous particles are tightly encapsulated by 3D graphene frameworks, which greatly improves the overall electrical conductivity and structural stability of the hybrids. With the help of synergistic effects between U-Fe3O4 and graphene frameworks, U-Fe3O4@RGO anode demonstrates high reversible capacity, excellent cycling stability (2292mAhg−1 specific capacity after 500 cycles at 0.5Ag−1) and outstanding rate capability (439mAhg−1 specific capacity at 10Ag−1).

Bio-inspired sandwich-structured carbon/silicon/titanium-oxide nanofibers composite as an anode material for lithium-ion batteries

A bio-inspired sandwich-structured carbon/silicon/titanium-oxide nanofibers composite is fabricated based on the self-assembly technique by using cellulose substance as both the carbon source and the structural scaffold. It holds the hierarchical structure of the initial cellulose substance. And it is composed of thin silicon layer sandwiched between the carbon nanofiber and the outer titanium oxide coating layer consisting of anatase titania nanoparticles with oxygen defects. Owing to the synergetic effect of the porous carbon nanofiber and titanium oxide coating layer, as well as its unique three-dimensional network structure, this nanocomposite shows enhanced lithium storage properties. For the composite with 24.1wt% of titanium oxide, it delivers a stable reversible capacity of ca. 792.6mAhg−1 at a current density of 100mAg−1 after 160 discharge/charge cycles, which superiors to the nanofibrous silicon and carbon/silicon matters as well as the carbon/silicon/titanium-oxide composites with low titanium oxide content therein.

Laser in-situ synthesis of SnO2/N-doped graphene nanocomposite with enhanced lithium storage properties based on both alloying and insertion reactions

This paper reported a SnO2/N-doped graphene nanocomposite (SnO2/N-Gr) electrode which was prepared by a laser in-situ synthesis method. When demonstrated as anodes for lithium storage, the SnO2/N-Gr electrode showed improved lithium storage capacities and rate performance. In details, a reversible capacity of 830mAhg−1 was obtained after 300 cycles at a current density of 300mAg−1, and when the current density increased up to 3Ag−1, the SnO2/N-Gr electrode revealed a high reversible capacity of 600mAhg−1. It was proven that the excellent electrochemical performance mainly related to a hybrid lithium storage mechanism which combined with alloying and insertion reactions. By introducing huge numbers of micropores and defects on graphene sheets, N-doping increased the number of hosts for lithium insertion and enhanced the Li+ diffusion rate in graphene sheets, so both of lithium storage capacities and rate performance were effectively improved. The SnO2/N-Gr electrode had a short preparing procedure and good electrochemical performance, which hold potential for development of next generation lithium ion batteries with high specific capacities and good rate performance.

Construction of hybrid hollow architectures by in-situ rooting ultrafine ZnS nanorods within porous carbon polyhedra for enhanced lithium storage properties

Constructing hybrid hollow composites based on metal chalcogenides and nanocarbon materials is of great interests for electrochemical energy storage applications. In this work, a metal-organic framework (MOF)-engaged template strategy is developed to mediate the in-situ formation of ultrafine ZnS nanorods rooted in the hollow carbon polyhedra (denoted as ZnS NR@HCP). The synthesis is realized through a simultaneous carbonization and sulfidation of Zn-based zeolitic imidazolate framework (ZIF-8) template at elevated temperatures. The as-prepared hybrid hollow composites exhibit a highly porous and robust structure with intimate coupling between ZnS nanorods and carbon supports, which provides facile ion and electron transport pathways as well as high mechanical stability. When evaluated as anode materials for lithium-ion batteries, these unique ZnS NR@HCP architectures manifest excellent lithium-storage performance in terms of ultrahigh reversible specific capacity (840mAhg−1 after 300 cycles at 600mAg−1) and exceptional rate capability (1388, 1063, 962, 824 and 608mAhg−1 at 100, 200, 400, 800 and 1600mAg−1).

Synthesis of N-doped carbon-coated Zn–Sn mixed oxide cubes/graphene composite with enhanced lithium storage properties

Developing the superior electrode materials with large reversible capacity, excellent rate capability and long cycling stability for high-performance lithium-ion batteries (LIBs) is highly desirable for electric vehicles and hybrid electronic vehicles. Herein, three-dimensional N-doped carbon (NC)-coated Zn–Sn mixed oxide (ZTO) cubes dispersed on reduced graphene oxide (ZTO@NC/RGO) composite are synthesized via a facile strategy combined with the hydrothermal treatment and carbonization of conductive polypyrrole. In this unique architecture, the ultrathin NC shells are interconnected through RGO and construct a continuous 3D conductive network, which provides a very efficient channel for electron transport. Furthermore, the flexible and high-conducting reduced graphene oxide and carbon shells can accommodate the mechanical stress induced by the volume change of ZTO cubes during lithiation as well as prohibit the aggregation of ZTO cubes, which would maintain the structural and electrical integrity of the ZTO@NC/RGO electrode during the lithiation/delithiation processes. Benefiting from the advantages of intrinsic architecture, as LIBs anodes, ZTO@NC/RGO exhibits enhanced lithium storage properties, delivering a large specific capacity of 732.8 mAh g−1 at a current density of 100 mA g−1 after 50 cycles, and presenting good rate capability.

Synthesis of hierarchical spindle-like Mn2O3 for lithium ion batteries with enhanced lithium storage properties

Hierarchical spindle-like Mn2O3 has been synthesized through a facile hydrothermal procedure without any hard template followed by thermal annealing in air at 600 °C for 2 h. When served as anode material for lithium-ion batteries, the Mn2O3 anode could maintain a reversible capacity as high as 993.1 mAh g−1 at a current density of 400 mA g−1 after 180 cycles. Moreover, it also shows excellent long cyclability, maintaining a reversible capacity of 823.8 mAh g−1 at a high current density of 800 mA g−1 after 390 cycles. The superior electrochemical performances of the spindle-like Mn2O3 anode should be attributed to the unique nanostructure, wherein the nanoparticles can buffer large volume change during long-term cycling process and provide shorter diffusion pathways for lithium ions and electrons on electrode. In addition, the porous surface can enhance effective contact with electrolyte.

Facile fabrication of ZnO–CuO porous hybrid microspheres as lithium ion battery anodes with enhanced cyclability

ZnO–CuO porous hybrid microspheres were successfully produced through a facile aging process of zinc citrate solid microspheres in copper sulfate solution combined with the subsequent annealing treatment in air atmosphere. The electrochemical performance investigation suggests that the harvested ZnO–CuO porous hybrid microspheres illustrate much higher specific capacity and better cycling stability than single ZnO counterparts. A reversible capacity of 585 mAh·g−1 can be acquired for ZnO–CuO porous hybrid microspheres after cycling 500 times at a current density of 200 mA·g−1. The porous configuration and the incorporation of CuO are responsible for the enhanced lithium storage properties of ZnO–CuO hybrids.

Ultrathin MoS2 sheets supported on N-rich carbon nitride nanospheres with enhanced lithium storage properties

Deciphering the structural and volume changes occurring during electrode reactions in lithium-ion batteries is perhaps a boon for high energy density batteries. Here, we report the synthesis of 3D network of dichalcogenide molybdenum disulfide (MoS2) encapsulated over nitrogen rich graphitic carbon nitride nanosphere (g-C3N4) forming an interconnected and uniform g-C3N4/MoS2 scaffolds. The crystallinity, phase purity, morphological features and elemental composition were evaluated through XRD, FESEM, TEM, HRTEM, BET and XPS analyses. The electrochemical properties of N-rich g-C3N4/MoS2 scaffolds were investigated as potential anode materials for lithium-ion batteries. Electrochemical testing of the g-C3N4/MoS2 constructured electrode delivered reversible capacity of 857mAhg−1at 0.1C rate after fifty cycles and exhibited a high rate performance with reversible capacity of 383mAhg−1 at 10C rate (higher than theoretical capacity of graphite, 372mAhg−1). The superior electrochemical property of g-C3N4/MoS2 is attributed to N-rich carbon support which favors better electronic conductivity, and affords more sites for Li+ ions. The nitrogen rich carbon nitride accommodates volume changes caused during repeated charge/discharges and maintains high structural integrity and specific capacity.

One-pot fabrication of graphene sheets decorated Co2P-Co hollow nanospheres for advanced lithium ion battery anodes

The fabrication of Co2P-Co (Co-P composites) hollow nanospheres with graphene sheets decoration through one-pot solution approach is demonstrated and their potential as the anode materials for lithium ion batteries is assessed. A large specific capacity of 929mAhg−1 can be retained for Co-P/graphene nanocomposites at 100mAg−1 after 200 cycles. When cycled at a large current density of 2.0C, the Co-P/graphene nanocomposites deliver a decent reversible capacity of 567mAhg−1, which is much higher than the theoretical capacity of traditional graphite anode (372mAhg−1). The obviously enhanced lithium storage properties of Co-P/graphene nanocomposites are put down to the dual modification of graphene sheets and metal Co as well as their hollow structures.

Ordered mesoporous carbon-supported CoFe2O4 composite with enhanced lithium storage properties

A high and stable reversible specific capacity (1277.7 mAh g−1) was successfully achieved by the CoFe2O4/ordered mesoporous carbon nanohybrids (CFO/CMK-3) composite anode at the current density of 0.1 A g−1 after 100 cycles. CFO/CMK-3 electrode also exhibited a stable capacity up to 733.2 and 482.6 mAh g−1 at the current densities of 0.5 and 1 A g−1 after 500 cycles, respectively. The CFO particles were found to be uniformly distributed inside the pore channels of CMK-3. Structure characterization before and after 100 tests revealed that the specific CMK-3 mesoporous structure and CFO crystallites remained unchanged. The stability of the anode composite stability and the rapid redox capability of CFO gave rise to superior lithium storage capacity and excellent cycling stability. CFO/CMK-3 showed a great promise to serve as anode for high-performance lithium-ion battery.

Mesoporous nanoplate TiO2/reduced graphene oxide composites with enhanced lithium storage properties

Mesoporous nanomaterial has been extensively studied in high-performance anode materials, because of their large electrolyte–electrode contact area, small volume change, high safety and enhanced specific capacity during discharge/charge process. Herein, we use titanium trichloride as Ti-sources and adjust the pH of solvent to successfully prepare mesoporous nanoplate TiO2 on reduced graphene oxide (RGO) nanosheets via two-step hydrothermal treatment. Benefiting from the unique structure, as-prepared mesoporous nanoplate TiO2/RGO composites present high reversible capacity and strong cycling stability (high capacity of ∼200mAhg−1 at 1.2C after 300 cycles) as anode materials for Li ion batteries (LIBs).

Embedding CoS2 nanoparticles in N-doped carbon nanotube hollow frameworks for enhanced lithium storage properties

The construction of metal sulfides-carbon nanocomposites with a hollow structure is highly attractive for various energy storage and conversion technologies. Herein, we report a facile two-step method for preparing a nanocomposite with CoS2 nanoparticles in N-doped carbon nanotube hollow frameworks (NCNTFs). Starting from zeolitic imidazolate framework-67 (ZIF-67) particles, in situ reduced metallic cobalt nanocrystals expedite the formation of the hierarchical hollow frameworks from staggered carbon nanotubes via a carbonization process. After a follow-up sulfidation reaction with sulfur powder, the embedded cobalt crystals are transformed into CoS2 nanoparticles. Benefitting from the robust hollow frameworks made of N-doped carbon nanotubes and highly active CoS2 ultrafine nanoparticles, this advanced nanocomposite shows greatly enhanced lithium storage properties when evaluated as an electrode for lithium-ion batteries. Impressively, the resultant CoS2/NCNTF material delivers a high specific capacity of ∼937 mAh·g–1 at a current density of 1.0 A·g–1 with a cycle life longer than 160 cycles.

Multi-functional integration of pore P25@C@MoS2 core-double shell nanostructures as robust ternary anodes with enhanced lithium storage properties

Ternary anodes have attracted more and more attention due to the characteristic advantages resulting from the effect integration of three different materials on the lithium storage mechanism with functional interfaces interaction. However, clarifying the distribution and interaction of carbon, MoS2 and TiO2 in the MoS2/C/TiO2 composite, which is helpful for the understanding of the formation and lithium storage mechanism of the ternary anodes, is a well-known challenge. Herein, a novel pore core-double shell nanostructure of P25@carbon network supported few-layer MoS2 nanosheet (P25@C@FL-MoS2) is successfully synthesized by a one-pot hydrothermal approach. The distribution and interaction of the carbon, MoS2 and TiO2 in the obtained P25@C@FL-MoS2 hybrid are systematically characterized by transmission electron microscopy, Raman spectra and X-ray photoelectron spectroscopy analysis et al. It is found that the carbon serves as binder, which supports few-layer MoS2 shell and coats the P25 core via TiOC bonds at the same time. Such multi-functional integration with smart structure and strong interfacial contact generates favorable structure stability and interfacial pseudocapacity-like storage mechanism. As a consequence, superior cycling and rate capacity of the muti-functional integration ternary P25@C@FL-MoS2 anode are achieved.

Metal–organic framework-induced formation of core–shell ZnCo2O4 spheres composed by nanoparticles with enhanced lithium storage properties

In this study, core–shell ZnCo2O4 spheres composed by nanoparticles were prepared via constructing a novel zeolitic imidazolate framework (ZIF) sphere with the assistance of citric acid.