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A hierarchically 3D structured milled lamellar MoS2/nano-silicon@carbon hybrid with medium capacity and long-term lifespan is designed by a green and scalable approach using ball milling process and spray-drying/pyrolysis routes. The microspheres consist of low-content nano-silicon (20 wt%), milled lamellar MoS2 sheets and porous carbon skeletons. A mixture of silicon nanoparticles and MoS2 flakes serves as an inner core, while porous carbon pyrolyzed from petroleum pitch acts as a protective shell. The particular architecture affords robust mechanical support, abundant buffering space and enhanced electrical conductivity, thus effectively accommodating drastic volume variation during repetitive Li+ intercalation/extraction. The Si/MoS2@C hybrid delivers a high initial discharge specific capacity of 1257.8 mA h g−1 and exhibits a reversible capacity of 767.52 mA h g−1 at a current density 100 mA g-1 after 250 cycles. Most impressively, the electrode depicts a superior long-cycling durability with a discharge capacity of 537.6 mA h g−1 even after 1200 cycles at a current density of 500 mA g-1. Meanwhile, the hybrid also shows excellent rate performance such as 388.1 mA h g−1 even at a large current density of 3000 mA g-1.

Novel porous nano-silicon/TiO2/rGO@carbon anodes with superior lifespan and desirable cycling stability are prepared by a step-wise synthetic procedure. The hybrid exhibits a high specific capacity of 1073.43 mAh g−1 at a current density of 500 mA g−1. Additionally, it delivers a reversible capacity of 724.08 mAh g−1 at 1000 mA g−1 even after 1000 long-term cycles. Simultaneously, a large average capacity is reinstated after cycling at high rates, such as 994.76, 743.33, and 599.70 mAh g−1 at 1000, 2000, and 3000 mA g−1, respectively. The greatly ameliorative electrochemical characteristics could be attributed to the abundant buffering space of hierarchical architecture, good separation of mechanically robust anatase-TiO2, sustainable confinement of elastic carbon skeletons, as well as improved electrical conductivity of rGO, which could suppress drastic volume variations and promote multiple Li+/electron transport without distinct pulverization.

In this work, a graphene-decorated Li2S cathode has been prepared via spray drying method using Li2SO4, graphene oxide and sucrose as raw materials. During spray drying, sucrose melts and embeds Li2SO4 when Li2SO4 were sprayed out with graphene oxide and sucrose, and becomes sphere particles. The as-prepared Li2S composite was received after a heat treatment under nitrogen atmosphere. X-ray diffraction patterns confirm the cubic structure of Li2S and scanning electron microscope images reveal that Li2S and carbon components stay in sphere structure with diameter around 20 μm. The sphere Li2S composite shows enhanced performance when acts as cathode. Under current density of 100 mA g−1, a specific discharge capacity of 778 mAh g−1 has been achieved and the battery cycled over 60 rounds. Furtherly, the sphere composite was coupled with silicon/graphite anode to construct full cell system, suggesting large possibility to work with the current lithium-ion battery anodes.

Both freshwater shortage and energy crisis are global issues. Herein, we present a double-function system of faradaic desalination and a redox flow battery consisting of VCl3|NaI redox flow electrodes and a feed stream. The system has a nominal cell potential (E0 = +0.79 V). During the discharge process, the salt ions in the feed are extracted by the redox reaction of the flow electrodes, which is indicated by salt removal. Stable and reversible salt removal capacity and electricity can be achieved up to 30 cycles. The energy consumption is as low as 10.27 kJ mol-1 salt. The energy efficiency is as high as 50% in the current aqueous redox flow battery. With energy recovery, the desalination energy consumption decreases greatly to 5.38 kJ mol-1; this is the lowest reported value to date. This "redox flow battery desalination generator" can be operated in a voltage range of 0.3-1.1 V. Our research provides a novel method for obtaining energy-saving desalination and redox flow batteries.

In this article, the synthesis of CoP microflake and Co 3 O 4 microsphere via a simple two-step strategy is presented. Startlingly, electrochemical performance comparisons of as-prepared two compounds as anode materials for lithium ion batteries (LIBs) are investigated. CoP microflake depicts a prominent capacity retention and a long cycle life with a discharge capacity of 619.2 mAh/g at a high current density of 1000 mA/g after 800 cycles, while Co 3 O 4 microsphere only shows a capacity of 93.1 mAh/g after 800 cycles under the current of 1000 mA/g. This work may offer a facile approach for the preparation of metal phosphides as promising anodes for LIBs.

Carbon-coated core-shell structure artificial graphite@plasma nano-silicon@carbon (AG@PNSi@C) composite, applying as lithium ion battery anode material, has been prepared via spray drying method. The plasma nano-silicon (

One-dimensional mesoporous CoP nanorods have been successfully synthesized via a facile hydrothermal method and subsequent low temperature thermal phosphorization treatment. At the current density of 500 mA g− 1, CoP nanorods as anode materials for lithium ion batteries deliver a high discharge capacity of 894 mAh g−1 after 300 cycles with a coulombic efficiency over 99%. Even at a high current rate of 4000 mA g-1, the discharge capacity of the CoP electrode can still retain 467 mAh g-1. The results suggest that the introduction of Co element and the special mesoporous nanorods play important roles in enhancing the electrochemical property. Therefore, this rod-like CoP electrode is competent as promising anode materials for high-performance lithium-ion batteries.

Rose-like ZnCo2O4 was directly grown on nickel foam via a facile hydrothermal method combined with a subsequent annealing treatment. Self-assembly ZnCo2O4 manifests three dimensional hierarchical architecture and mitigates the volume expansion. The obtained ZnCo2O4 has a large specific surface area of 37.84 m2 g−1 and a sufficient pore volume of 0.23 cm3 g−1. Porous ZnCo2O4 as a binder-free anode for sodium ion batteries exhibits improved sodium storage capability, ameliorative cycling performance and good structure stability. It remains discharge capacities of 444 and 250 mAh g−1 after 70 cycles at the current densities of 100 and 500 mA g−1, respectively.

The novel Sb 2 S 3 /lotus-pollen composites are fabricated for the first time in the literature through hydrothermal method followed by calcination treatment. As an anode material in lithium ion batteries, the Sb 2 S 3 /lotus-pollen composites deliver an initial discharge capacity of 988 mA h g −1 at 100 mA g −1 and maintain a capacity of 591 mA h g −1 after 100 cycles. Even up to 1000 and 2000 mA g −1 , the Sb 2 S 3 /lotus-pollen composites still obtain capacity of 436 and 365 mA h g −1 , respectively, indicating a good rate capability. Compared with pure Sb 2 S 3 , the enhanced electrochemical performance of Sb 2 S 3 /lotus-pollen may be ascribed to the improved electron conductivity and volume buffering effect provided by the biological carbon skeleton of lotus-pollen.

In this research, a novel hollow nanobarrel-like ZnCo2O4 has been designed and synthesized via a simple solvothermal method and subsequent calcination. The obtained samples were systematically characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), N2 adsorption-desorption and X-ray photoelectron spectrometer (XPS). This special hollow structure could not only relieve the volume expansion effect, but also facilitate the diffusion of lithium ion. We obtained a reversible lithium storage capacity of 1350 mAh g-1 even after 300 cycles at a current density of 500 mA g-1 with a voltage window of 0.01-3.0 V. As-prepared samples demonstrate the high reversible capacity and excellent cycle life. The good cycling capability and high rate performance suggest that the ZCO will be an attractive anode material for lithium ion batteries.

Hierarchical CoMn2O4 microspheres assembled by nanoparticles have been successfully synthesized by a facile hydrothermal method and a subsequent annealing treatment. XRD detection indicate the crystal structure. SEM and TEM results reveal the 3-dimensional porous and micro-/nanostructural microsphere assembled by nanoparticles with a size of 20-100 nm. The CoMn2O4 electrode show initial specific discharge capacity of approximately 1546 mAh/g at the current rates 100 mA/g with a coulombic efficiency of 66.7% and remarkable specific capacities (1029-485 mAh/g) at various current rates (100-2800 mA/g).

In this work, we develop an effective strategy to synthesize porous peanut-like ZnCo2O4 (ZCO) decorated with graphene/Carbon nanotubes (CNTs) as an effective anode material for long cycling life lithium storage via a facile solvothermal process and rapid cold-quenching method. SEM and TEM characterizations show that graphene and CNTs serving as the elastic support and superior conductive network wrap the porous peanut-like ZCO, which can enhance electrochemical performance. The as-prepared ZnCo2O4/reduce graphene oxide/carbon nanotubes (ZCO/rGO/CNTs) delivers an initial discharge capacity of 1214.1 mAh g−1 at a current density of 500 mA g−1 and exhibits a high discharge capacity (1026.6 mAh g−1 after 200 cycles) when evaluated as anode materials of LIBs. More interestingly, the reversible capacity of the ZCO/rGO/CNTs even retains 728.6 mAh g−1 after 300 cycles even at a high current density of 1000 mA g−1. The good cycling capability, high rate performance and reliable electrode adaptability suggest that the ZCO/rGO/CNTs will be an attractive material for lithium ion batteries.

Ternary Sn-Sb-Co alloy particles embedded in reduced graphene oxide were fabricated via co-precipitation, followed by the special process of liquid nitrogen quenching and the subsequent thermal treatments (denoted as Sn-Sb-Co/rGO). When the Sn-Sb-Co/rGO hybrids were applied as anodes for rechargeable lithium ion battery, the electrodes deliver a reversible capacity of 937 mA h g−1 at 100 mA g−1 after 70 cycles, and reveal impressive discharge capacity of 754 mA h g−1 and 685 mA h g−1 at the current density of 500 mA g−1 and 1000 mA g−1, respectively. The well-improved electrochemical performance of the Sn-Sb-Co/rGO can be attributed to the conducting network of graphene, which greatly improves the conductivity of the electrode with volume buffering effect to prevent Sn-Sb-Co particles from aggregating.

This work presents a feasible route for the facile synthesis of three-dimensional (3D) hierarchical mesocarbon microbead (MCMB) as anodes for lithium ion batteries (LIBs) and sodium ion batteries (SIBs). The MCMB is oxidized by modified hummers method, and then the precursor is treated by hydrogen reduction to form the HMCMB. The HMCMB with graphene-like architecture has high specific surface, sufficient pore volume, and increased interlayer spacing, which can provide more active insertion/extraction sites and reduce the Li+/Na+ diffusion resistance. When employed as anode materials for LIBs and SIBs, HMCMB anodes exhibit improved lithium and sodium storage capability. The HMCMB delivers a higher reversible capacity (471.1 and 177.5 mAh g−1 at 100 mA g−1 after 100 cycles) and a good rate performance (250 and 121 mAh g−1 even at 1000 mA g−1) for LIBs and SIBs, respectively.

Porous ZnFe2O4 nanorods have been successfully prepared by a simple spray-drying process followed by sintering. The structure and morphology of the samples were characterized by X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy. The porous structured ZnFe2O4 materials are successfully used as potential anode material for lithium-ion batteries. Electrochemical results show that the anodes exhibit good cycling performance and rate capability. The anode exhibits initial discharge capacity of approximately 1459 mAh g−1 with an initial coulombic efficiency of 77.8% at a constant density of 100 mA g−1. The discharge capacity of the ZnFe2O4 retained 1458 mA h g−1 after 120 cycles at the current rate of 100 mA g−1 and 456 mA h g−1 could be obtained at the current density of 5000 mA g−1 after 200 cycles. The discharge capacities can still be as high as 778 mAh g−1 at a high rate of 3000 mA g−1. Such remarkable electrochemical properties could be ascribed to the unique porous morphology with large surface area and porosity that were beneficial to facilitate the diffusion of Li ions and electrolyte into the electrodes, meanwhile prevent volume expansion/contraction during lithiation/dislithiation processes.

The hierarchically structured cathode material Li1.165Mn0.501Ni0.167Co0.167O2 (LMNCO) is successfully synthesized via a facile ultrasonic-assisted co-precipitation method with a two-step heat treatment by adopting graphene and carbon nanotubes (CNTs) as functional framework and modified material. The structure and electrochemical performance degeneration mechanism were systematically investigated in this work. The obtained LMNCO microspheres possess a hierarchical nano-micropore structure assembled with nanosized building blocks, which originates from the oxidative decomposition of the transition metal carbonate precursor and carbonaceous materials accompanied with the release of CO2 (but still remain carbon residue). What’s more, the positive electrode exhibits enhanced specific capacities (276.6 mAh g−1 at 0.1 C), superior initial coulombic efficiency (80.3 %), remarkable rate capability (60.5 mAh g−1 at 10 C) and high Li+ diffusion coefficient (~10−9 cm2 s−1). The excellent performances can be attributed to the pore structure, small particle sizes, large specific surface area and enhanced electrical conductivity. (1 C = 250 mA g−1).

Cubic Spinel MnCo2O4/graphene sheets (MCO/GS) nanocomposites are synthesized by a facile hydrothermal method with a subsequent annealing process. Nano-sized MnCo2O4 particles are evenly embedded in paper-like graphene sheets, possessing a unique nanoparticles-on-sheets hybrid nanostructure, with particle size around 20–50 nm. Owing to the special nanoparticles-on-sheets structures, MCO/GS nanocomposites have an outstanding electrochemical performance for rechargeable energy storage devices. As an anode material for lithium-ion batteries, MCO/GS electrodes exhibit high reversible discharge capacities (1350.4 mAh g−1 at the initial rate of 100 mA g−1), excellent rate capability (462.1 mAh g−1 at a current rate of 4000 mA g−1) and outstanding cycling performance (584.3 mAh g−1 at 2000 mA g−1 after 250 cycles). Meanwhile, as an anode material for sodium-ion batteries, MCO/GS electrodes also exhibit comparably promising electrochemical characteristics. Greatly improved electrochemical properties can be assigned to the special advantageous nanostructures. Besides, the existence of graphene sheets is beneficial to the transportation of ions/electrons during battery operation. The outstanding electrochemical performance demonstrates that the lithium/sodium storage capability of MCO/GS nanocomposites is highly promising for high-capacity batteries.

Si@carbon composites have been successfully prepared via spray drying and subsequent calcination using PSA microspheres, nano-silicon and natural graphite as raw materials. Nano-silicon with a 20–100 nm particle size is prepared by radio-frequency electromagnetic induction. Such small nano-silicon particles can effectively accommodate the volume expansion of the Si@carbon anode. Additionally, the unique core–shell structure of Si@carbon composites can effectively alleviate the agglomeration of nano-silicon particles. Electrochemical tests show that the Si/carbon electrode delivers a high initial discharge capacity of approximately 1404.27 mAh g−1 with an initial coulombic efficiency of 82.4 %. The discharge specific capacity remains as high as 73.6 % after 100 charging-discharging cycles, demonstrating the electrode material’s good cycle stability. In addition, the corresponding specific capacity of the Si@carbon composites electrode remains at around 1150 mAh g−1 at a current density of 1 A g−1. And when the current density is 0.1 A g−1, its specific capacity can still remain at around 920 mAh g−1, indicating excellent capacity reversibility. Therefore, Si@carbon composites are superior anode materials for high-performance Li-ion batteries.

Zn2+ ion substituted nickel ferrite nanomaterials with the chemical formula Ni1−xZnxFe2O4 for x = 0, 0.3, 0.5, 0.7 and 1 have been synthesized by a facile green-chemical hydrothermal method as anode materials in lithium ion battery. The morphology and structure of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The physical and electrochemical properties were tested by electrochemical system. Furthermore, the energetic and electronic properties of the samples were investigated by density functional calculations. The results suggest that Zn substitution can affect the conduction performance of the zinc - nickel ferrite. Meanwhile, electrochemical results show that an enhancement in the capacity with increasing Zn concentration is observed especially for x = 0.3 which exhibit high discharge capacity of 1416 mAh g−1at the end of 100th cycle. Moreover, the theoretical research method with high yield synthesis strategy described in the present work holds promise for the general fabrication of other metallic elements substitution in complex transition metal oxides for high power LIBs.

A unique intertwined structure of silicon-based composite (Si@TiO2&CNTs) has been synthesized by sol–gel and spray drying methods. The Si@TiO2&CNTs is mainly composed of three kinds of materials:the prepared nanosilicon particles, TiO2, and carbon nanotubes (CNTs). A layer of TiO2 particles is found effective for enhancing the electrical conductivity and structure stability of the silicon particles. Additionally, the twisted CNTs are beneficial to build a better conductive network, consequently improving the anode working conditions when the cell is charged or discharged. As a lithium ion battery anode, a specific capacity of approximately 1521 mAh g−1 after 100 cycles is obtained.

Polyhedral Ti-doped Co3O4 nanoparticles with a diameter of about 100–300 nm have been easily synthesized by a co-heat precipitated method. The structure and morphology of the materials were characterized by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The electrochemical measurements were implemented on half coin cells. Galvanostatic charge, discharge performance, cyclic voltammetry and impedance measurement were utilized to investigate the electrochemical properties. The Ti-doped Co3O4 electrodes showed superior performance compared with the undoped Co3O4 electrodes, including the enhanced rate capability, and better capacity retention. At current densities of 500 mA g−1, the Ti-doped Co3O4 electrodes exhibited initial capacities of 1173.6 and 849.0 mAh g−1, and the capacities were maintained at 850.3 and 838.6 mAh g−1 after 120 cycles. These excellent electrochemical properties can be attributed to the nanoscale structure and Ti doping.

A silicon based composite (Si@SiO2/CNTs) with outstanding electrochemistry performance has been easily synthesized using a spray drying method; The composite microsphere is mainly made up of carbon nanotubes and the prepared nano silicon particles. With the help of a silane coupling agent, carbon nanotubes tightly intertwined with nano silicon particles and formed microspheres together. On the surface of the prepared nano silicon particles, a layer of oxide film plays a role as a barrier to reduce the rupture of the particles during the lithium intercalation/extraction process. In addition, the added twisted carbon nanotubes can help to maintain the conductive network, thus stabilizing the electrode working environment during the lithium intercalation/extraction process. As a superior anode material, an initial specific discharge capacity of approximately 2846.9 mAh g−1 with a coulombic efficiency of 86 % and a reversible specific capacity of 2035.9 mAh g−1 after 100 cycles at a constant density of 500 mA g−1 are obtained.

Nanocrystalline ZnFe2O4, Zn0.5Mn0.5Fe2O4, and Zn0.5Mn0.5Fe2O4@CNT composites have been successfully prepared by a facile and high-yield co-precipitation method. All the samples as the anode materials were characterized by X-ray diffraction, thermogravimetry, and electrochemical measurements. It has been found that the appropriate Mn doping and CNTs intertwining actively affect the formation of uniform morphology and improve the cycling stability and rate capability. The Zn0.5Mn0.5Fe2O4@CNT composites exhibit excellent electrochemical performance as the anode material, with enhanced reversible capacity (1374.8 mAh g−1 after 100 cycles at the current density of 100 mA g−1) and good rate capability (933.5 mAh g−1 at 500 mA g−1, 809.9 mAh g−1 at 1000 mA g−1, 634.2 mAh g−1 at 1500 mA g−1). We also present the crystal structure and Li-ion insertion mechanism for the above materials. Our work displays the Li storage matrix model of the ZMFO electrode which may offer a novel way for the investigation of the LIBs with excellent electrochemical performance and perfect structural stability .

Lamella SnSbCu x /MCMB/carbon composite were prepared by a multi-step synthesis method for high stability and long life lithium ion battery electrodes. The lamella composite were synthesized via co-precipitation method combining with high-speed ball milling and subsequent pyrolysis. The resultant composite are consisted of nano SnSbCu x particles, lamella mesophase carbon microbeads (MCMB, after ball milling) and amorphous carbon coating pyrolyzed from phenolic resin. The lamella MCMB was treated as the inner terrace, which offered efficient electron conducting pathway for connection of nano SnSbCu x particle and pyrolysis carbon. With the increasing of the content of inactive element Cu, the SnSbCu x /MCMB/carbon composite are propitious to improve the cycling performance. When cycled at a constant current of 100 mA g −1 between 0.01 and 2.0 V, the coulombic efficiency of first cycle exceeds 88.45% and the reversible capacity of 100th cycle attains to 485 mAh g −1 (91.4% capacity retention) in SnSbCu 0.5 /MCMB/carbon alloy anodes.

The Li-rich layered cathode material Li1.165Mn0.501Ni0.167Co0.167O2 with porous structure has been successfully synthesized through a facile co-precipitation approach followed with a high-temperature calcination treatment, adopting polymer microsphere (PSA) as a template and conductive agent. The PSA-assisted Li1.165Mn0.501Ni0.167Co0.167O2 composite exhibits remarkably improved cycling stability and rate capability compared with the bare composite. It delivers a high initial discharge capacity of 267.0 mA h g−1 at 0.1 C (1 C=250 mA g−1) between 2.0 V and 4.65 V. A discharge capacity of 214.9 mA h g −1 is still obtained after 100 cycles. Furthermore, the diffusion coefficients of Li+ investigated by the cyclic voltammetry technique are approximately 10−15–10−14 cm2 s−1. Such outstanding performance is mainly ascribed to: on one hand, the carbon residue of PSA after being calcined at high temperature contributes to enhance the electronic conductivity of the electrode and alleviates the volume changes during the Li+-insertion/extraction, leading to an improved rate capability; on the other hand, the unique porous structure and small particle size are conductive to increase the exposed electrochemical active surface, shorten Li+ diffusion distance and thus enhance the lithium storage capacity.

Porous NiCo2O4 ellipsoids supported by flexile carbon nanotubes (denoted as NCO/CNTs) were successfully synthesized by a facile hydrothermal method followed by subsequent annealing in air. The structure and morphology of the materials were characterized by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. When evaluated as anode materials for lithium-ion batteries (LIBs), the NCO/CNTs composites exhibit a high and stable reversible capacity (1273.8 mA h g−1 at 500 mA g−1), excellent rate capability (593.0 mA h g−1 at 4000 mA g−1), and long cycling stability (no capacity fade over 200 cycles). The improved performance of these LIBs can be attributed to the unique 3D porous NCO/CNTs composite frameworks, which will enhance electrical conductivity of the materials, facilitate fast ion/electron transport through the electrode, and accommodate massive volume expansion/contraction during cycling. Furthermore, the synthetic strategy is simple but very effective, it can be easily extended to prepare many other metal oxides with the CNTs acting as the conductive network and used as promising anode materials for high-performance LIBs.

3-Dimensional cuboid structured ZnFe2O4@C nano-whiskers anode materials have been successfully synthesized via an in situ graft copolymerization method and the subsequent calcination process. Polystyrene-acrylonitrile (PSA) serves as the coating layer, which plays an important role in the calcination process. The final electrode materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results of electrochemical tests demonstrate an excellent electrochemical performance, including good rate capability (over 700 mA h g−1 at the current density of 3.2 A g−1) and good cycling performance (a reversible capacity of 1722 mA h g−1 after 120 cycles with coulombic efficiency of 98.4%). Therefore, we believe that the proposed work may be a potential method to assist ZnFe2O4 to be a quite promising alternative anode material for lithium-ion batteries (LIBs).

Fe3O4 has long been regarded as one of the most promising anode materials for lithium ion batteries due to its high theoretical capacity, low cost, and nontoxic properties. Here, we report a facile hydrothermal way to perform carbonization of poly (ST-AN) (PSA) to obtain a PSA-Fe3O4@C3Dmesoporousmicrosphere. (*) Its electrochemical performance as an anode material was evaluated by cyclic voltammetry (CV) and galvanostatic charge/discharge experiments. The PSA-Fe3O4@C electrode delivers a capacity of 1130 mA h g−1 at 0.5 C, in contrast to that of the CA (Citric Acid)-Fe3O4@C (1111 mA h g−1) and Fe3O4 (817 mA h g−1). The improvements can be attributed to the unique composition and microstructure that endow the electrode with large contact area between material and electrolyte, short diffusion path for lithium ions transportation in the active material, low electron transfer resistance from a current collector to the active material, and large buffering space for volume change during charging/discharging process.

Carbon nanotubes (CNTs) are adopted to modify ZnCo 2 O 4 (ZCO) electrode, and a novel porous polyhedral structure ZCO/CNTs composites are prepared by a facile and scalable hydrothermal process, and the pure ZCO with cubic structure is also synthesized for comparison. The as-prepared materials are characterized by field emission scanning electron microscopy (FESEM). The results demonstrate that the introduced of CNTs has great effects on the nanostructure and electrochemical performance of the samples. The CNTs among the polyhedral structure ZCO/CNTs composites can provide better mechanical robustness, more contact between Li + and electrodes, and more effective electron transmission than the pure ZCO with cubic structure. When tested as anode materials for lithium ion batteries, the ZCO/CNTs composites exhibit a high initial coulombic efficiency of 83.9%, a high specific capacity of ∼864.6 mAh g −1 at a current rate of 100 mA g −1 after 150 cycles, as well as a good rate capability at elevated current rates, such as, ∼924.3 and ∼605.7 mAh g −1 at current rates of 500 and 2000 mA g −1 , respectively. This work would be meaningful in the preparation of complex oxides/carbon composites with porous nanostructure as anodes for LIBs.

Novel cubic aggregated CoFe2O4 nanoparticles are successfully synthesized by hydrothermal method. Electrochemical results show that the CoFe2O4 nanoparticles exhibit good cycling performance and excellent rate capability. The first discharge and charge capacities of these nanoparticles are 1672.8 mAh g−1 and 1309.1 mAh g−1, respectively, with an initial coulombic efficiency of 78.3%. The electrode can retain a high capacity of 1133.5 mAh g−1 after 120 cycles at a current density of 100 mA g−1. Moreover, it could still maintain a reversible capacity of 679 mAh g−1 even at a high current density of 3.2 A g−1. The improved electrochemical performance can be ascribed to the hierarchical cubic aggregated structural with large specific surface area and lots of interspaces between the particles, which not only can effectively increase the active surface area, but also can make better penetration of the electrolyte and accommodate the volume expansion.

A high performance surface modified Li1.2Mn0.534Ni0.133Co0.133O2 cathode with graphene and CNTs (GNL-modified LMNCO) has been synthesized via a simple ultrasonic dispersion approach. Its morphology and electrochemical performance are investigated thoroughly in this work. Typically, the GNL-modified LMNCO demonstrates an initial discharge capacity of 285.8 mAh g−1, showing initial coulombic efficiency of 83.3%. In addition, impressive discharge capacity of 162.3 and 123.5 mAh g−1 are obtained at 5 and 10 C, respectively. More satisfactorily, it reveals high capacity retention of 217.9 mAh g−1 even after the 180th cycle. The extraordinary electrochemical performance of the GNL-modified LMNCO can be ascribed to the unique conducting network of graphene and CNTs coating on the particles, which greatly improves the conductivity of the electrode and enhances the diffusion coefficient of the Li+. Most significantly, a high-voltage and high-power electrochemical energy storage devices of lithium-ion battery (LIB) full cell has been simultaneously assembled with the GNL-modified LMNCO as cathode and silicon/graphite/amorphous carbon (Si/C) composite as anode, whose properties outclass many other systems of LIB full cells. Therefore, the acquaintance of the compatibility of the Li-rich cathode and Si/C composite anode for high-voltage and high-energy LIB full cells should attract more research efforts in the future.

SnSbCo/MCMB/C composite with flake structure were prepared by stepwise synthesis method. Firstly, SnSbCo nanoparticles were fabricated by co-precipitation, and then nanosized SnSbCo alloy were embedded in mesocarbon microbeads (MCMB) by ball-milling to synthesize primitive SnSbCo/MCMB hybrids, followed by carbonization of phenolic resin to produce an outer layer of carbon coating. The crystal structure, morphology and electrochemical properties of the SnSbCo/MCMB/C composite were evaluated by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and galvanostatical cycling tests. Compared with bare SnSbCo alloy and SnSbCo/MCMB hybrids, the efficiently enhanced electrochemical performance of SnSbCo/MCMB/C composite were mainly ascribed to the improved electron conductivity and volume buffering effect provided by the amorphous carbon coating. The resultant SnSbCo/MCMB/C composite delivered an initial discharge capacity of 848 mAh g −1 under 100 mA g −1 , with a good capacity retention of 85.6% after 70 cycles. The composite also exhibited excellent rate capability of 603 mAh g −1 and 405 mAh g −1 at the current density of 200 mA g −1 and 1000 mA g −1 , respectively.

In this work, organic carbon modified NiCo 2 O 4 (NCO@C) nanocomposite with porous 3-dimensional (3D) structure was successfully synthesized by a facile hydrothermal method in D-glucose-mediated processes. A detailed research reveals that D-glucose molecules play an important role in the formation of the porous 3D structure and also provide a conductive carbon network within the NCO@C nanocomposite materials. Such a porous 3D interconnected carbonaceous nanostructure applied as electrode material for lithium-ion batteries (LIBs) shows that its reversible capacity, cycling stability, and rate capability are significantly enhanced in comparison with those of pure NiCo 2 O 4 (NCO) electrode. The as-prepared NCO@C composite electrode with porous 3D nanostructure displays a higher discharge specific capacity of 1389 mAh g −1 even after 180 cycles at a current rate of 0.55 C. Furthermore, this composite material also presents a high rate capacity, when the current rate gradually increases to 0.55 C, 1.1 C, 2.2 C, and 4.4 C, the reversible capacity can still render about 1082, 1029, 850, and 625 mAh g −1 , respectively. The enhanced electrochemical performance indicated that the NCO@C nanocomposite might be a very promising candidate to replace conventional graphite-based anode materials for LIBs.

The commercialized LIBs employing graphite as anodes currently suffer a series of problems from the safety problem, low theoretical capacity (372 mAh g−1) and bad rate capability. Herein, hollow microspheres MnFe2O4 (MFO) and nanoparticles MFO have been synthesized. Compared with the nanoparticles MFO, the hollow microspheres MFO as an anode material with novel structure demonstrate superior electrochemical performance, with large specific reversible capacity (1100 mAh g−1 at the specific current of 0.5 C after 100 cycles), high rate capability (more than 500 mAh g−1 even at 5.0 C) and good cyclability with little fading (1.4 % after 100 cycles). The excellent cycling performance is associated with the hollow microsphere structure with large specific surface areas, which can accommodate the severe mechanism strains and ensure more contact area between active material and electrolyte, thus good for diffusion of electrolyte and provide more reaction sites. This work presents a meaningful way for the preparation of MFO with different morphology as superior alternative anodes for lithium ion batteries.

The Li-rich layered Li1 + x(Mn0.6Ni0.2Co0.2)1 − xO2 (x = 0.14, 0.165, 0.19) cathode materials have been successfully synthesized through a one-pot facile co-precipitation route. The synthesized MCO3 (M = Mn0.6Ni0.2Co0.2) precursor mixing with Li2CO3 was annealed at 500 °C and calcinated at 900 °C. The morphology and structure of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results indicate that the sample Li1.165Mn0.501Ni0.167Co0.167O2 (x = 0.165) exhibits the most outstanding electrochemical performance, which may be ascribed to uniform particle size and high crystallinity. It delivers an initial discharge-specific capacity of approximately 241.7 mAh g−1 with an initial coulombic efficiency of 70.3 % at a constant density of 25 mA g−1. A reversible discharge-specific capacity of approximately 207.2 mAh g−1 is still obtained after 100 cycles. The discharge capacities of nearly 226.8, 194.4, 158.9, 143.7, 116.8, 97.5, and 47.6 mAh g−1 can also be attained under 0.1 C, 0.2 C, 0.5 C, 1 C, 2 C, 5 C, and 10 C (1 C = 250 mA g−1), respectively. The Li-rich layered Li1.165Mn0.501Ni0.167Co0.167O2 will be a promising cathode material for advanced lithium-ion batteries.

A high yield and low-cost high-energy wet ball milling method is used for producing nano-flake Si@SiO2 as an anode material for Li-ion batteries. After a two-step ball milling (coarse milling and fine milling) process, the irregular plate-like micrometric Si (average particle size is 27.4 μm) is fractured into nano-flake Si@SiO2 (average particle size is 154.8 nm) with small crystalline grains and abundant grain boundaries. Due to the significant changes of the prepared nano-flake Si@SiO2 in the surface composition, particle size and crystal structure, the ball milled Si shows better electrochemical performance compared with the as-received micrometric Si. And the fine milled Si shows the best electrochemical properties with a high initial coulombic efficiency of 84.6% and a specific capacity of 1920.4 mA h g−1 at a current density of 100 mA g−1 after 100 cycles.

A silicon/silver/carbon (Si/Ag/C) composite with a core-core-shell structure has been synthesized via a simple method based on pyrolysis of an organic carbon source and silver mirror reaction. The Si and Ag nanoparticles are served as cores, while the porous amorphous carbon layer formed from pyrolysis of citric acid is served as shell. The porous amorphous carbon layer and highly conductive Ag nanoparticles can effectively alleviate the volume change of Si nanoparticles during lithiation/delithiation process and provide sufficient electrical conductivity for Si nanoparticles. As an anode material, the obtained Si/Ag/C composite exhibits excellent electrochemical performances, including high initial coulombic efficiency (85.6 % at 200 mA g−1), stable cycling performance (a discharge capacity of 2006.3 mA g−1 at 200 mA g−1 after 100 cycles), and excellent rate performance (a discharge capacity of 826.4 mA h g−1 at 3 A g−1). This simple method may open up an effective way to make other anode and cathode materials for commercial lithium-ion battery.

An interweaved silicon monoxide/graphite/carbon nanotubes&carbon nanofibers (SiO/G/CNTs&CNFs) composite has been easily synthesized by using high-energy wet ball milling, spray drying in combination with a subsequent chemical vapor deposition method. CNTs&CNFs grow on the interface and the internal interspace of the spherical composite composed of SiO and graphite during the calcination process. The existence of CNTs&CNFs and graphite not only provides a buffer medium to accommodate the volume expansion of SiO during the electrochemical reaction process, but also provides high electrical conductivity for electrode material. When used as an anode material, a reversible specific capacity is approximate 672.3 mAh g−1 after 100 cycles at a current density of 100 mA g−1, which is about 1.8 times larger than that of the commercial graphite electrode (372 mA g−1). Due to the facile synthesis process of the composite and excellent performance of the as-prepared electrode, great commercial potential is envisioned.

Carbon-encapsulated Fe3O4 composites were successfully fabricated via hydrothermal method and examined by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The Fe3O4@C nanocomposite as an anode material with novel structure demonstrated excellent electrochemical performance, with enhanced specific reversible capacity (950 mAh/g at the current density of 50 mA/g after 50 cycles), remarkable rate capability (more than 650 mAh/g even at the current density of 1,000 mA/g) and good cycle ability with less capacity fading (2.4 % after 50 cycles). Two factors have been attributed to the ultrahigh electrochemical performance: Firstly, the 30- to 50-nm spherical structure with a short diffusion pathway and the amorphous carbon layer could not only provide extra space for buffering the volumetric change during the continuous charging–discharging but also improve the whole conductivity of the Fe3O4@C nanocomposite electrode; secondly, the synergistic effects of Fe3O4 and carbon could avoid Fe3O4 direct exposure to the electrolyte and maintain the structural stabilization of Fe3O4@C nanocomposite. It was suggested that the Fe3O4@C nanocomposite could be suitable as an alternative anode for lithium-ion batteries with a high application potential.

Amorphous and crystalline hybrid structure Co2SnO4/C composites have been prepared by a facile way using coprecipitation process and high-energy ball milling technology. Electrochemical performance tests show that the composite anodes could maintain reversible capacity of higher than 550 mAh g−1 up to 100 cycles, much better than that of pure Co2SnO4 (194.1 mAh g−1). These materials also present better rate performance with fairly stable capacity retention when the current ranges from 100 to 500 mA g−1. Impedance measurements confirm that these composites are more beneficial for lithium diffusion compared to pure Co2SnO4. The graphite carbon not only buffers the volume expansion-related cracking but also provides excellent conductivity for this material.

A coralline-like lithium-rich layered cathode material with homogeneous composition of Li 1.20 Mn 0.54 Ni 0.13 Co 0.13 O 2 has been successfully synthesized via a facile ethanolamine (EA)-mediated hydrothermal method route, with subsequent calcination at 850 °C. An initial specific discharge capacity of 250.2 mAh g −1 and a reversible specific capacity of 210.2 mAh g −1 after 100 cycles at a constant density of 25 mA g −1 (1 C = 250 mA g −1 ) are acquired. Even at 10 C, it still delivers a discharge capacity of approximately 100 mA h g −1 , thereby indicating its excellent high power performance. The sample also shows enhanced cycling performance with 88.5%, 79.9% and 90.5% of capacity retention after 100 cycles at 0.5, 5 and 10 C rates, respectively. Besides, 84.5% of initial capacity is retained even after 200 cycles at 10 C. Consequently, the fascinating electrochemical performance may facilitate the coralline-like LMNCO composite to be a promising alternative cathode for LIBs with a high application potential.

The growth of three-dimensional (3D) porous NiCo2O4 nanowire arrays on a carbon fiber cloth (denoted as NCO@CFC) via a facile low-cost solution method combined with a subsequent annealing treatment is reported. The structure and morphology of the materials were characterized by X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. Owing to the unique 3D hierarchical architecture, the NCO@CFC nanowires as a flexible electrode material for lithium-ion batteries exhibit a stable cycling performance (92.3% retention after 100 cycles), a fairly high rate capacity (507 mA h g−1 at 4000 mA g−1), and an enhanced lithium storage capacity. When employed as an electrode material for sodium-ion batteries, the NCO@CFC is investigated in comparison with a 3D ordered array structure and exhibits similar charge/discharge characteristics and a feasible electrochemical performance. The greatly improved electrochemical performance could be ascribed to the 3D porous nanostructure of the NCO@CFC nanowire arrays together with a novel carbon skeleton, which provides enough space to allow volume expansion during the Li+/Na+ insertion/extraction process and facilitates rapid transport of ions and electrons.

Modified porous spherical Li1.2Mn0.534Ni0.133Co0.133O2 has been successfully synthesized via a co-precipitation method, adopting graphene and carbon nanotube conductive liquid (GNL) as a template and surface modified material. The unique porous structure and the larger specific surface area of the porous Li1.2Mn0.534Ni0.133Co0.133O2 contribute to both the increase in the first coulombic efficiency, from 76.3% to 82.0%, and the enhancement of the rate capability, demonstrating initial discharge capacities of 276.2, 245.8, 218.8, 203.9, 178.8, 135.9 and 97.5 mA h g−1 at different discharge rates of 0.1, 0.2, 0.5, 1.0, 2.0, 5.0 and 10 C, respectively. Even after suffering 100 cycles of charge–discharge, the porous Li-rich cathode can still deliver a discharge capacity of 235.5 mA h g−1, suggesting a high capacity retention of 86.2% compared to the initial discharge capacity (273.3 mA h g−1). Besides, the diffusion coefficient of the Li+ investigated by the cyclic voltammetry technique is approximately 10−12 cm2 s−1, indicating faster kinetics of the lithium ions for the modified porous Li1.2Mn0.534Ni0.133Co0.133O2 compared with the ordinary Li1.2Mn0.534Ni0.133Co0.133O2 (∼10−13 cm2 s−1). In fact, the introduction of GNL as a template not only leads to the porous structure of the Li-rich cathode material but also brings about improvement to the crystallinity and size of the grains, which can be ascribed to the combined effect of the GNL with the carbonate precursors of MCO3 (M = Mn, Ni, Co) during the recrystallization process.

Cubic spinel Co2SnO4/graphene sheets (Co2SnO4/G) nanocomposites are synthesized by a facile hydrothermal process in alkaline solution, using SnCl4 · 4H2O, CoCl2 · 6H2O and graphene oxide (GO) as the precursor. The structure and morphology of the resulting nanocomposites are characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Co2SnO4 nanoparticles are uniformly dispersed among graphene sheets, with a size of 80–150 nm. As anode material for lithium-ion batteries, the galvanostatic charge/discharge and cyclic voltammetry are conducted to indicate the electrochemical performance of Co2SnO4/G nanocomposites. Co2SnO4/G nanocomposites exhibit an improved electrochemical performance compared with pure Co2SnO4 nanoparticles, such as high reversible capacities, good cycling stability and excellent rate performance. The initial charge and discharge capacities are 996.1 mAh g−1 and 1424.8 mAh g−1. After 100 cycles, the reversible charge/discharge capacities still remain 1046/1061.1 mAh g−1 at the current density of 100 mA g−1. Co2SnO4 nanoparticles coated by Graphene sheets with superior electrochemical performance indicate that Co2SnO4/G nanocomposites are promising electrode materials used for high-storage lithium-ion batteries.

Novel corncob-shaped ZnFe2O4/C nanostructured composite materials have been successfully synthesized through a facile co-precipitation method with carbamide as carbonaceous matrix. The morphology and structure of the samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and transition electron microscopy (TEM), and the physical and electrochemical properties were tested by thermogravimetry and an electrochemical system. The corncob-shaped ZnFe2O4/C nanostructured anode materials exhibit outstanding cycling performance and rate capability in comparison with pure ZnFe2O4 anode materials. Electrochemical results show that the corncob-shaped ZnFe2O4/C nanocomposite materials exhibit an initial discharge capacity of approximately 1591.6 mA h g−1 with an initial coulombic efficiency of 80.4% at a constant density of 100 mA g−1. A reversible discharge capacity of 1119.1 mA h g−1 is still obtained after 100 cycles. The discharge capacities can still be as high as 889 mA h g−1 at a high rate of 4 C (1 C = 250 mA g−1). The excellent electrochemical performances are probably ascribed to the multiple synergetic factors that stem from their uniform nanoparticle size, complete crystallization with corncob shape, and organic pyrolysis of carbon inlaid in the corncob shaped nanostructure. The corncob-shaped ZnFe2O4/C nanocomposite will be a promising anode material for advanced lithium ion batteries.

ZnFe2O4 with inflorescence spicate architecture has been synthesized by a facile co-precipitation method with the presence of oxalic acid. The ZnFe2O4 as an anode material with novel morphological structure was emphasized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), Raman spectroscopy and so on. As an anode for LIBs, the inflorescence spicate ZnFe2O4 exhibits excellent electrochemical performance with an initial discharge capacity of 1647.2 mA h g−1, maintaining a reversible discharge capacity of 1398.1 mA h g−1 after 100 cycles at a current density of 100 mA g−1 (84.9% of the first discharge capacity) and favorable rate capacity (766 mA h g−1 at 1.2 A g−1). Such attractive performance is ascribed mainly to its unique inflorescence spicate electrode morphology, which can provide good electrical contact and conductivity, and provide a buffer medium to accommodate the volume expansion of electrode materials during the electrochemical reaction process. More importantly, this study not only provides a simple synthesis method for lithium-ion batteries, but also helps in designing novel electrode materials with high performance.

Pineapple-shaped ZnCo2O4 (ZCO) microspheres with a porous nanostructure are synthesized by a typical hydrothermal method and used as high performance anodes in Li-ion batteries. The microspheres show excellent cycling and rate performance. The initial discharge capacity of 1596.2 mA h g−1 and the reversible discharge capacity of 1132 mA h g−1 can be maintained after 120 cycles at a current density of 100 mA g−1. More interestingly, the reversible capacity as high as 800 mA h g−1 can be retained at a high current density of 1000 mA g−1 after 200 cycles. Surprisingly, the pineapple-shaped ZCO electrode exhibits a prominent rate performance, a reversible specific capacity of 1237 mA h g−1 and 505 mA h g−1 at current densities of 500 mA g−1 and 6000 mA g−1 respectively. In addition, the influence of distilled water and urea on the phase and morphology of the material is investigated by SEM and EDS. The results indicate that adding distilled water into the solvent could ensure the high purity of products with no loss of the Zn element. At the same time, the cycle performance can be effectively improved because of the more regular surface and the more stable structure of the microspheres with urea-assistance.