Excellent Lithium Storage Performance Research Articles

Hierarchical hybrid ZnFe2O4 nanoparticles/reduced graphene oxide composite with long-term and high-rate performance for lithium ion batteries

Hierarchical hybrid nanostructure of mesoporous ZnFe2O4 nanoparticles anchored on reduced graphene oxide (ZnFe2O4 NPs/rGO) has been successfully developed in this research via a fast low-temperature refluxing method and a subsequent-annealing treatment in N2. The unique mesoporous network structures of ZnFe2O4 NPs supported by flexible rGO sheets offer sufficient electrode-electrolyte contact, shorten Li+ ions diffusion distance, and thus greatly facilitate the electrochemical reactions via accommodating the volume change efficiently during cycling. Meanwhile, the conductive rGO matrix in the hybrid composite also ensures rapid electron transport to avoid the serve pulverization. Just based on such beneficial synergistic effect, the well-designed hierarchical hybrid ZnFe2O4 NPs/rGO composites present excellent lithium storage performance with high reversible discharge capacity, long-term cycle stability and superb high-rate capability when used as an anode for LIBs. A stable discharge capacity of as high as about 1106.7 mAh g−1 is well maintained even after 400 cycles at the current density of 200 mA g−1. We think this facile strategy could be further extended to the fabrication of other graphene-based electrodes for advanced energy applications.

Crosslinking-induced spontaneous growth: A novel strategy for synthesizing sandwich-type graphene@Fe3O4 dots/amorphous carbon with high lithium storage performance

Graphene/Fe3O4 hybrids have long been regarded as promising anode materials for lithium-ion batteries but remain significant bottlenecks of inhomogeneous/large Fe3O4 particle size and agglomeration during the repeated lithiation/dethiation process. By carefully selecting a metallo-organic molecule of ferrocene as the building block, a novel methodology has been explored herein for the preparation of sandwich-type graphene@Fe3O4 dots/amorphous carbon (G@Fe3O4/C) hybrids via a Friedel–Crafts crosslinking-induced spontaneous growth process. As prepared, ultra-small Fe3O4 dots of 2–3 nm are distributed uniformly in the amorphous carbon matrix coated on the surface of graphene. The ultralow size of Fe3O4 dots is able to minimize the volume change and Li+ migrating distance, while the carbon matrix and graphene framework prevent Fe3O4 dots from aggregation and offer a superior conductive skeleton along with a flexible framework to buffer the volume changes. In addition, the well-developed pore structure can accommodate the large volume change and facilitate the electrolyte diffusion/transfer, thereby increasing the ion accessible surface area, especially at high charge–discharge rates. Consequently, G@Fe3O4/C presents excellent lithium storage performances, including a highly reversible capacity of 1241 mAh g−1, an outstanding cycling stability after 200 cycles (1055 mAh g−1) and a superior high-rate capability (724 mAh g−1 at 5 A g−1).

Metal-organic frameworks derived yolk-shell ZnO/NiO microspheres as high-performance anode materials for lithium-ion batteries

Smart design and rational fabrication of novel anode materials with high specific capacity and long cycling stability are of significant importance for high-performance lithium-ion batteries (LIBs). Herein, nanostructured ZnO/NiO microspheres with a nanorods-composed shell and a microsphere yolk were synthesized by a controlled calcination treatment of the bimetallic organic frameworks in air. The obtained yolk-shell ZnO/NiO microspheres are observed to have an average diameter of 2 μm with uniform microsphere morphology from field-emission scanning electron microscopy and high-resolution transmission electron microscopy. Benefitting from the unique yolk-shell structure inherited from the bimetallic organic frameworks and the synergistic effect from ZnO and NiO, the as-prepared yolk-shell ZnO/NiO displays excellent lithium storage performance, including high specific capacity (1008.6 mAh g−1 at 0.1 A g−1 after 200 cycles), superior rate capability (437.1 mAh g−1 at 2 A g−1) and outstanding long-term cycling stability (592.4 mAh g−1 at 0.5 A g−1 after 1000 cycles), which demonstrates its promising potential as high-performance anode material for LIBs.

Preparation of Co3O4/Carbon Derived from Ionic Liquid and Its Application in Lithium-ion Batteries

In this paper, we report an ionic liquid derived Co3O4/Carbon (Co3O4/C) material synthesized by a carbothermic reduction followed by a low-temperature oxidation, which is certified by XRD and TEM. The as-synthesized Co3O4/C composite has a uniform structure with well-crystalized Co3O4 embedded in carbon matrix (onion-like carbon materials). The carbon held tightly on the Co3O4 particles can prevent the disintegration of Co3O4/C composite during cycling and, therefore, improve the integrity of the composite. Moreover, the carbon component of the composite can enhance the dynamic characteristic of the Co3O4/C composite, which can accelerate the electronic conductivity. The composite delivers excellent lithium storage performances with outstanding cycling performance (868 and 877mAhg−1 after 200 cycles at a current density of 89mAhg−1) and admirable rate capability (660 and 669mAhg−1 at a rate of 2C) in lithium-ion batteries (LIBs), showing great prospect as electrode material for LIBs.

Construction of N-doped carbon@MoSe2 core/branch nanostructure via simultaneous formation of core and branch for high-performance lithium-ion batteries

Here, we report a one-step simultaneous-construction approach to synthesize N-doped carbon@MoSe2 core/branch nanostructures by heating a mixture of MoO3/PANI hybrids and Se powders in argon atmosphere, without requiring a cumbersome multi-step process or highly toxic reducing agents. It is found that in the construction process, PANI played a crucial role in the reduction of MoO3 and Se to form MoSe2 nanosheet branches, while PANI itself was decomposed and carbonized into N-doped carbon nanorod cores. Interestingly, the coexistence of 1D and 2D nanostructures in the N-doped carbon@MoSe2 core/branch system leads to excellent lithium storage performance, including a large discharging capacity of 1275mAhg−1, a high reversible lithium extraction capacity of 928mAhg−1 and a coulombic efficiency of 72.8%. After 100 cycles, the NDC@MS electrode still delivers a reversible capacity of 906mAhg−1 with a capacity retention ratio of 97.6%. The superior electrochemical properties can be attributed to the unique core/branch nanostructure of NDC@MS and the synergistic effect between the N-doped carbon nanorod cores and MoSe2 nanosheet branches.

Mn doped FeCO3/reduced graphene composite as anode material for high performance lithium-ion batteries

Abstract FeCO3 (FCO), FeCO3/rGO (FCOG) and Fe0.8Mn0.2CO3/rGO (MFCOG) nanocomposites are synthesized via a facile and controllable one-step hydrothermal process. XRD, SEM and TEM characterizations show that Mn ions can successfully substitute for partial iron atoms in FeCO3 nanocrystals without any crystal structure changes. Applied as anodes for lithium-ion batteries (LIBs), MFCOG delivers optimal electrochemical performance with a reversible capacity of 1223 mAh g−1 at a current density of 0.2 A g−1 after 120 cycles. Furthermore, MFCOG maintains a specific capacity of 613 mAh g−1 at a high current density of 1.6 A g−1, showing the enhanced rate capabilities and stable cycling performance. It indicates that the excellent lithium storage performance of MFCOG is mainly related to its well-designed nanostructure of doped metal carbonates and rGO nanosheets with high electrical conductivity which can work as effective conductive matrix and restrain the agglomeration of FeCO3, leading to synergistic effects on improving the structural integrity and accommodating the volume changes of MFCOG during the process of lithium intercalation/deintercalation.

A heart-coronary arteries structure of carbon nanofibers/graphene/silicon composite anode for high performance lithium ion batteries

In an animal body, coronary arteries cover around the whole heart and supply the necessary oxygen and nutrition so that the heart muscle can survive as well as can pump blood in and out very efficiently. Inspired by this, we have designed a novel heart-coronary arteries structured electrode by electrospinning carbon nanofibers to cover active anode graphene/silicon particles. Electrospun high conductive nanofibers serve as veins and arteries to enhance the electron transportation and improve the electrochemical properties of the active “heart” particles. This flexible binder free carbon nanofibers/graphene/silicon electrode consists of millions of heart-coronary arteries cells. Besides, in the graphene/silicon “hearts”, graphene network improves the electrical conductivity of silicon nanopaticles, buffers the volume change of silicon, and prevents them from directly contacting with electrolyte. As expected, this novel composite electrode demonstrates excellent lithium storage performance with a 86.5% capacity retention after 200 cycles, along with a high rate performance with a 543 mAh g−1 capacity at the rate of 1000 mA g−1.

The synergistic effect supported Li4Ti5O12 anode with advanced lithium storage performance

Low specific capacity and poor electrical conductivity are the two intrinsic problems of spinel lithium titanate (Li4Ti5O12), which limit the practical use of Li4Ti5O12 anode in lithium-ion batteries. Herein, we demonstrate that the capacity and rate performance of Li4Ti5O12 anodes can be greatly improved by the synergistic effect of facile hierarchical structure design and in-situ decoration of tiny TiO2. The as-prepared ultrafine nanowire assembled and TiO2in-situ decorated clew-like Li4Ti5O12 anode is able to deliver a ultrahigh reversible specific capacity of 195.2 mAh g−1 at 20 mA g−1 and 125 mAh g−1 at 5000 mA g−1 even after 5000 cycles, exhibiting excellent lithium storage performance and cycling stability. Thus obtained outstanding electrochemical performance largely surpasses that of reportedly state-of-the-art LTO-based anode materials. This work may pave the way to facilely prepare advanced Li4Ti5O12-based anode materials for lithium-ion batteries.

Novel porous starfish-like Co3O4@nitrogen-doped carbon as an advanced anode for lithium-ion batteries

A Co-based metal-organic framework (Co-MOF) with a unique three-dimensional starfish-like nanostructure was successfully synthesized using a simple ultrasonic method. After subsequent carbonization and oxidation, a nanocomposite of nitrogen-doped carbon with a Co3O4 coating (Co3O4@N-C) with a porous starfish-like nanostructure was obtained. The final hybrid exhibited excellent lithium storage performance when evaluated as an anode material in a lithiumion battery. A remarkable and stable discharge capacity of 795 mAh·g−1 was maintained at 0.5 A·g−1 after 300 cycles. Excellent rate capability was also obtained. In addition, a full Co3O4@N-C/LiFePO4 battery displayed stable capacity retention of 95% after 100 cycles. This excellent lithium storage performance is attributed to the unique porous starfish-like structure, which effectively buffers the volume expansion that occurs during Li+ insertion/deinsertion. Meanwhile, the nitrogendoped carbon coating enhances the electrical conductivity and provides a buffer layer to accommodate the volume change and accelerate the formation of a stable solid electrolyte interface layer.

Silica-Derived Hydrophobic Colloidal Nano-Si for Lithium-Ion Batteries.

Silica can be converted to silicon by magnesium reduction. Here, this classical reaction is renovated for more efficient preparation of silicon nanoparticles (nano-Si). By reducing the particle size of the starting materials, the reaction can be completed within 10 min by mechanical milling at ambient temperature. The obtained nano-Si with high surface reactivity are directly reacted with 1-pentanol to form an alkoxyl-functionalized hydrophobic colloid, which significantly simplifies the separation process and minimizes the loss of small Si particles. Nano-Si in 5 g scale can be obtained in one single batch with laboratory scale setups with very high yield of 89%. Utilizing the excellent dispersion in ethanol of the alkoxyl-functionalized nano-Si, surface carbon coating can be readily achieved by using ethanol soluble oligomeric phenolic resin as the precursor. The nano-Si after carbon coating exhibit excellent lithium storage performance comparable to the state of the art Si-based anode materials, featured for the high reversible capacity of 1756 mAh·g-1 after 500 cycles at a current density of 2.1 A·g-1. The preparation approach will effectively promote the development of nano-Si-based anode materials for lithium-ion batteries.

Aluminum fumarate-based metal organic frameworks with tremella-like structure as ultrafast and stable anode for lithium-ion batteries

Metal organic frameworks (MOFs) with the unique advantages of high surface area and easily controllable structure have attracted significant attention as electrode materials for various batteries. In this work, aluminum fumarate-based MOFs are prepared through complexation of fumaric acid with different aluminum salts. Interestingly, hierarchical tremella-like structured aluminum fumarates composed of intertangled ultrathin nanosheets are obtained using Al(NO3)3·9H2O and AlCl3·6H2O as aluminum salts. When being used as the anode material for lithium-ion batteries, the aluminum fumarates MOFs deliver a considerably improved performance compared to the pristine organic fumaric acid. Excellent high-rate behavior and long-term cycling stability are obtained for the aluminum fumarate electrodes. At a current density of 37.5mAg−1, a reversible capacity of 392mAhg−1 is obtained without any capacity-fading up to 100 cycles. Even at an extremely high current density of 37.5Ag−1, aluminum fumarate retains a capacity of 258mAhg−1. The electrochemical process of aluminum fumarate electrode is elucidated through in-depth electrochemical and spectroscopic studies. The low impedance, reversible lithiation/delithiation process, and structural stability of aluminum fumarate electrode during electrochemical cycling are found to be the main factors for its excellent lithium storage 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).

Facile template-free one-pot fabrication of ZnCo2O4 nanospheres for advanced lithium storage capability

Large-scale ZnCo2O4 nanospheres with an average diameter of 350 nm were developed via a hydrothermal method. By adjusting the molar ratio of polyvinyl pyrrolidone (PVP), the ZnCo2O4 nanospheres can be facilely designed. Meanwhile, controlled experiment factors, namely the concentration of reagents, play important roles in the formation of the nanospheres. The possible mechanism for the nanostructures formation was discussed. In addition, when tested as anode materials for lithium-ion batteries, these ZnCo2O4 nanospheres have exhibited excellent lithium-storage performance.

A novel porous reduced microcrystalline graphene oxide supported Fe3O4@C nanoparticle composite as anode material with excellent lithium storage performances

The competitiveness of reduced graphene oxide (GO) based composite can be significantly improved when the raw material of GO become the low-cost microcrystalline graphite mine. Herein, we first successfully fabricate high-quality microcrystalline graphite GO (MGO) with small size <1μm by a modified pressurized oxidation approach. Subsequently, Fe3O4@C/PrMGO composite is simply constructed by using porous reduced MGO (PrMGO) to support carbon coated Fe3O4 nanoparticles (Fe3O4@C NPs). The Fe3O4@C/PrMGO composite exhibits high reversible capacity and excellent cyclic stability that a high reversible capacity of 1216mAhg−1 is received after 392 cycles at 100mAg−1. Meanwhile, the composite possesses high rate retentions, superior structural and cycling stability, which are further revealed by rate test, SEM and EIS analyses. The significant advantages of Fe3O4@C/PrMGO composite (low cost, facile operation and high electrochemical performances) endow the composite to be practically promising anode material for next-generation LIBs. This research supplies a new strategy to fabricate low-cost and high performances MGO-based anode materials.

Flower-like C@SnO X @C hollow nanostructures with enhanced electrochemical properties for lithium storage

Hollow nanostructures have attracted considerable attention owing to their large surface area, tunable cavity, and low density. In this study, a unique flower-like C@SnOX@C hollow nanostructure (denoted as C@SnOX@C-1) was synthesized through a novel one-pot approach. The C@SnOX@C-1 had a hollow carbon core and interlaced petals on the shell. Each petal was a SnO2 nanosheet coated with an ultrathin carbon layer ~2 nm thick. The generation of the hollow carbon core, the growth of the SnO2 nanosheets, and the coating of the carbon layers were simultaneously completed via a hydrothermal process using resorcinol-formaldehyde resin-coated SiO2 nanospheres, tin chloride, urea, and glucose as precursors. The resultant architecture with a large surface area exhibited excellent lithium-storage performance, delivering a high reversible capacity of 756.9 mA·h·g–1 at a current density of 100 mA·g–1 after 100 cycles. Open image in new window

Mesoporous Silicon Anodes by Using Polybenzimidazole Derived Pyrrolic N-Enriched Carbon toward High-Energy Li-Ion Batteries

The silicon anode holds great potential for next-generation lithium-ion batteries in view of its high gravimetric capacity and natural abundance. The main challenges associated with silicon are the structural degradation and instability caused by huge volume change upon cycling. We report herein polybenzimidazole (PBI) derived pyrrolic N-enriched carbon as an ideal encapsulation onto microsized silicon spheres, which is achieved by an aerosol-assisted assembly combined with a simple physisorption process. The new polymer derived carbon endows silicon with the structural and compositional characteristics of intrinsic high electronic conductivity, abundant pyrrolic nitrogen, and structure robustness. The resulting mesoporous Si-PBI carbon composite exhibits excellent lithium storage performance in terms of high reversible specific capacity of 2172 mAh g–1, superior rate capability (1186 mAh g–1 at 5 A g–1), and prolonged cycling life. As a result, a fabricated Si/LiCoO2 full battery demonstrates high energy...

Optimization of NiFe2O4/rGO composite electrode for lithium-ion batteries

The combination of carbon compositing and the proper choice of binders in one system offer an effective strategy for improving electrode performance for lithium ion batteries (LIBs). Here, we focus on the optimization of reduced graphene oxide content in NiFe2O4/reduced graphene oxide (abbreviated to NiFe2O4/rGO) composites and the proper choice of binders to enhance the cycling stability of the NiFe2O4 electrode. The NiFe2O4/rGO composites were fabricated by a hydrothermal-annealing method, in which the mean size of spinel NiFe2O4 nanoparticles was approximately 20nm. When tested as anode materials for LIBs, the NiFe2O4/rGO electrodes with carboxymethylcellulose (CMC) binder exhibited excellent lithium-storage performance including high reversible capacity, good cycling durability and high-rate capability. The capacity could be retained as high as 1105mAhg−1 at a current density of 100mAg−1 for over 50 cycles, even cycled at higher current density of 1000mAg−1, a capacity of 800mAhg−1can be obtained, whereas the electrode with the polyvinylidene fluoride (PVDF) binder suffered from rapid capacity decay under the same test conditions. As a result, the NiFe2O4/rGO composites with CMC binder electrode in this work are promising as anodes for high-performance LIBs, resulting from the synergistic effect of optimal graphene content and proper choice of binder.

Ultrathin mesoporous ZnCo2O4 nanosheets as anode materials for high-performance lithium-ion batteries

Transition-metal oxides have been widely explored as the anode materials for lithium-ion batteries (LIBs) because of its low cost and high energy/power density. However, the electrode pulverization and capacity fading during cycling lead to poor cycling performance. Herein, ultrathin ZnCo2O4 nanosheets with desired mesoporosity and high surface area are prepared by a facile hydrothermal approach. Such ZnCo2O4 nanostructures show excellent lithium storage performance as anode materials for LIBs. At a current density of 1 A g−1, the ultrathin ZnCo2O4 nanosheets present an initial specific capacity of 1251 mAh g−1 and the specific capacity remains at ∼810 mAh g−1 even after 200 discharge–charge cycles.

Enhanced Structural and Electrochemical Stability of Self-Similar Rice-Shaped SnO2 Nanoparticles.

A facile one-pot hydrothermal strategy is applied to prepare Co and F codoped SnO2 (Co-F/SnO2) nanoparticles, which exhibit a unique rice-shaped self-similar structure. Compared with the pristine and Co-doped counterparts (SnO2 and Co/SnO2), the Co-F/SnO2 electrode demonstrates higher capacity, better cyclability, and rate capability as anode material for lithium ion batteries (LIBs). A high charge capacity of 800 mAh g-1 can be successfully delivered after 50 cycles at 0.1 C, and a high reversible capacity of 700 mAh g-1 could be retained after 100 cycles at 5 C. The excellent lithium storage performances of the Co-F/SnO2 nanoparticles could be attributed to the synergetic effects of the doped Co and F, as well as the unique hierarchical self-similar structure with moderate oxygen defect and inactive pillars, which not only facilitates the fast diffusion of Li ions, but also stabilizes the structure during the electrochemical cycling.

Facile Synthesis of Layer Structured GeP3/C with Stable Chemical Bonding for Enhanced Lithium-Ion Storage

Recently, metal phosphides have been investigated as potential anode materials because of higher specific capacity compared with those of carbonaceous materials. However, the rapid capacity fade upon cycling leads to poor durability and short cycle life, which cannot meet the need of lithium-ion batteries with high energy density. Herein, we report a layer-structured GeP3/C nanocomposite anode material with high performance prepared by a facial and large-scale ball milling method via in-situ mechanical reaction. The P-O-C bonds are formed in the composite, leading to close contact between GeP3 and carbon. As a result, the GeP3/C anode displays excellent lithium storage performance with a high reversible capacity up to 1109 mA h g−1 after 130 cycles at a current density of 0.1 A g−1. Even at high current densities of 2 and 5 A g−1, the reversible capacities are still as high as 590 and 425 mA h g−1, respectively. This suggests that the GeP3/C composite is promising to achieve high-energy lithium-ion batteries and the mechanical milling is an efficient method to fabricate such composite electrode materials especially for large-scale application.