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In this work, the commercial detonation nanodiamonds (DNDs) are introduced to the anodes of lithium ion battery (LIBs) consisting of anatase titanium dioxide (TiO2) and synthesized graphite by a microwave treatment process. The compound TiO2/DND/graphite anodes are favorable for improving the LIB performance, where the LIBs have lithium storage capacities of 540 mA h g−1 at 0.5 C after 100 cycles and 300 mA h g−1 at 5 C after 1000 cycles, which are greatly higher than the theoretical data (168 mA h g−1) from TiO2 anode alone. The high capacity, as well as excellent cycling performance and stability of the LIBs, are attributed to the synergistic effect of DND (larger surface area, low expansion, high lithium adsorption capacity, chemical inertness), TiO2 (high Li+ insertion/extraction voltage, robust structural stability, lower volumetric expansion) and the improved ionic conductivity of the anode with additional fabricated graphitic powders. [ABSTRACT FROM AUTHOR]

Reasonably designing and synthesizing advanced electrode materials is significant to enhance the electrochemical performance of lithium ion batteries (LIBs). Herein, a metal–organic framework (MOF, Mil‐125) was used as a precursor and template to successfully synthesize the porous mooncake‐shaped Li4Ti5O12 (LTO) anode material assembled from nanoparticles. Even more critical, SmF3 was used to modify the prepared porous mooncake‐shaped LTO material. The SmF3‐modified LTO maintained a porous mooncake‐shaped structure with a large specific surface area, and the SmF3 nanoparticles were observed to be attach on the surface of the LTO material. It has been proven that the SmF3 modification can further facilitate the transition from Ti4+ to Ti3+, reduce the polarization of electrode, decrease charge transfer impedance (Rct) and solid electrolyte interface impedance (Rsei), and increase the lithium ion diffusion coefficient (DLi), thereby enhancing the electrochemical performance of LTO. Therefore, the porous mooncake‐shaped LTO modified using 2 wt % SmF3 displays a large specific discharge capacity of 143.8 mAh g−1 with an increment of 79.16 % compared to pure LTO at a high rate of 10 C (1 C=170 mAh g−1), and shows a high retention rate of 96.4 % after 500 cycles at 5 C‐rate. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) used as popular coatings can improve the electrochemical performance of electrodes greatly; however, uniform coatings of PPy on nanostructures is a challenging task in a solution system. Substitution for liquid phase polymerization reaction, herein a developed evaporation method is reported to make pyrrole vapor in situ polymerization on CuO arrays for the uniform PPy coatings. With the help of this uniform PPy coatings, the unique structure of arrayed CuO film can well maintain the stability of mechanical structures and has rapid transmission of lithium ions and electrons during charge/discharge processes, hence harvesting a high lithium storage. Electrochemical tests indicate that PPy can not only enhance the specific capacities of CuO anodes greatly but also improve the cyclic stability at a high-current density. The specific capacity of the CuO@PPy integrated anode can be up to 561 mAh g−1 at 1 C after 100 cycles, which is increased by almost 33% than that of the pure CuO anode. [ABSTRACT FROM AUTHOR]

Abstract Fe 3 O 4 @C composite was designed and synthesized by a facile one-step solvothermal route as an anode material for Li-ion batteries (LIBs). The carbon shell can effectively prevent the aggregation and buffer the volume expansion during charge/discharge process. The electrochemical performance displays that the Fe 3 O 4 @C composite exhibits high reversible capacity and good cycling performance. In particular, it displays excellent cycling stability at 2 C rate (640.5/642.2 mA h g−1 after 1000 cycles). The results indicate a simple and useful route to prepare Fe 3 O 4 @C composite as a promising LIBs anode material. Graphical abstract Fe 3 O 4 @C composite with high reversible capacity and good cycling performance has been synthesized by a facile one-step solvothermal route as an anode material for Li-ion batteries (LIBs). fx1 Highlights • Fe 3 O 4 @C composite has been synthesized by a facile one-step solvothermal route. • Fe 3 O 4 @C composite has been studied as an anode material for LIBs. • Fe 3 O 4 @C composite displays high reversible capacity and good cycling performance. [ABSTRACT FROM AUTHOR]

A new three-dimensional (3D) sandwich-like Si/Polyaniline/Graphene nanoarchitecture anode for lithium ion batteries (LIBs) is successfully fabricated through an easy approach. In this nanoarchitecture, the in-situ polymerized electronic conductive polyaniline (PAni) hydrogel, acting as “glue”, agglutinates tightly to both the silicon nanoparticles (SiNPs) and graphene sheets, forming efficient conductive networks with high elastic modulus and high tensile strength. This mechanically robust nanoarchitecture can endure the great volume change of silicon and retain structural stability during Li-ion insertion/extraction. The electrodes consisting of this 3D sandwich-like Si/Polyaniline/Graphene nanoarchitecture reveal excellent electrochemical performance. The progress made in this work provides an easy and scalable route for preparing Si-based anode materials with high performance for advanced LIBs. [ABSTRACT FROM AUTHOR]

The charge/discharge mechanism and electrochemical performance of Zn 3 V 3 O 8 as anode for Li-ion batteries are systematically studied. Theoretical calculation predicts that Zn 3 V 3 O 8 can act as a host for Li storage, and a possible diffusion way of Li-ions within the crystal structure is calculated via first principle methods. Experimentally, Zn 3 V 3 O 8 nanosheets with porous architecture are fabricated via a facile hydrothermal pretreatment and subsequent sintering. The Zn 3 V 3 O 8 shows superior electrochemical performance with graphite electric additive, exhibiting discharge/charge capacity of 541/537 mAh g −1 after 200 cycles at a specific current of 120 mA g −1 . The Li-storage mechanism is also studied via ex-situ XRD, and the maintenance of main diffraction peaks during lithiation/delithiation process suggests a possible intercalation/extraction mechanism of the Zn 3 V 3 O 8 . [ABSTRACT FROM AUTHOR]

Silicon (Si) is promising for high capacity anodes in lithium‐ion batteries due to its high theoretical capacity, low working potential, and natural abundance. However, there are two main drawbacks that impede its further practical applications. One is the huge volume expansion generating during lithiation and delithiation progresses, which leads to severe structural pulverization and subsequently rapid capacity fading of the electrode. The other is the relatively low intrinsic electronic conductivity, therefore, seriously impacting the rate performance. In the past decades, numerous efforts have been devoted for improving the cycling stability and rate capability by rational designs of different nanostructures of Si materials and incorporations with some conductive agents. In this review, the authors summarize the exciting recent research works and focus on not only the synthesis techniques, but also the composition strategies of silicon nanostructures. The advantages and disadvantages of the nanostructures as well as the perspective of this research field are also discussed. We aim to give some reference for engineering application on Si anodes in lithium ion batteries. [ABSTRACT FROM AUTHOR]

In lithium ion batteries anode material is very crucial. Exploring the high-performance anode materials remains a great challenge. Here, Ti 2 Nb 10 O 29 /Ag composite was obtained. Electrochemical measurements demonstrate that Ti 2 Nb 10 O 29 /Ag composite shows good electrochemical performance than pure Ti 2 Nb 10 O 29 , mostly due to enhanced electronic conductivity after Ag-coating. The specific capacities of Ti 2 Nb 10 O 29 /Ag composite can be as high as 253 and 173 mAh g −1 at 1 and 10C, respectively, and the specific capacity is 132 mAh g −1 at 20C. Moreover, the Ti 2 Nb 10 O 29 /Ag composite exhibited excellent cyclic stability, even after 500 cycles, its specific capacity at 10C still stabilized at a large value of 142 mAh g −1 , which was in sharp contrast to the corresponding values of pure Ti 2 Nb 10 O 29 (68 mAh g −1 ). The high electrochemical performance demonstrated that Ti 2 Nb 10 O 29 /Ag composite is highly promising anode materials for Li-ion batteries. [ABSTRACT FROM AUTHOR]

The composite of Co 3 O 4 , Co and graphitized carbon is synthesized by carbonization and cobalt-catalyzed-graphitization of carboxymethyl chitosan, followed by low-temperature thermal oxidation. At the high temperature, the Co(+2) is reduced to metallic Co and the produced Co acts as a catalyst for the graphitization of the pyrolytic carbon. The low-temperature oxidation is conducted to selectively oxidize Co to Co 3 O 4 while the carbon remains unreacted. The structure analysis indicates that three crystal phases (graphite, metallic Co, Co 3 O 4 ) accompanied with amorphous carbon are co-existed in the composite. Morphological results demonstrate that a lot of graphite grains around the Co element are distributed in the carbon. The electrochemical testing results indicate that the composite shows good electrochemical performance. It delivers a reversible capacity of 843 mAh g −1 at low current density, and remains 88.9% after 60 cycles at 200 mA g −1 . Even performed at 1 A g −1 , it also exhibits 493 mAh g −1 . The performance improvement is mainly due to the high capacity of Co 3 O 4 , high conductivity of graphitic carbon and metallic cobalt, the porous structure offering enough ion transport pathways and relieving the strain during cycling. [ABSTRACT FROM AUTHOR]

As a high-capacity hydrogen storage material, MgH 2 also shows specific advantages for LIB anode. In this work, MgH 2 and MgH 2 -C films were prepared by magnetron sputtering and hydrogenation treatment, and their microstructural and electrochemical properties were investigated. Through the conversion reaction of MgH 2 with lithium (MgH 2 + 2Li + → Mg + 2LiH), the reversible lithium storage was achieved in the MgH 2 and MgH 2 -C films. The MgH 2 film delivers the initial discharge capacity of 313.9 μAh cm −2 (∼2956 mAh g −1 ), the discharge and charge capacities related to the conversion process are respectively 150.0 μAh cm −2 (∼1412 mAh g −1 ) and 55.0 μAh cm −2 (∼518 mAh g -1 ), with the inefficiency of 63.3%. The GITT measurement determined the equilibrium potential of this conversion reaction to be 0.55 V vs. Li/Li + , and the voltage hysteresis between discharge and charge is only 10 mV vs. Li/Li + . In comparison with the MgH 2 film, the MgH 2 -C film has smaller crystallite size, lower polarization effect and structural stability, but exhibiting lower capacity and equally poor cyclic performance. The poor cycle life of MgH 2 -C film electrode is due to the large irreversibility of conversion reaction of MgH 2 , instead of structural damage of film electrode during cycling. [ABSTRACT FROM AUTHOR]

Cubic MnCO 3 @C composite was first synthesized using one-pot hydrothermal method. The prepared cubic MnCO 3 @C presented a homogeneous core-shell structure, which was composed of cubic MnCO 3 as core, a mixture of amorphous carbon and MnCO 3 as shell, and a separating interlayer. Compared to pure MnCO 3 , core-shell structured MnCO 3 @C exhibited better cycling stability, rate performance and recovery capability. It delivered a reversible capacity of 1020 mAh g −1 which was 94.7% of the initial capacity, and a recovery capacity of 862 mAh g −1 after 80 cycles under current density from 100 mA g −1 to 10000 mA g −1 . The superior electrochemical performance of MnCO 3 @C could be attributed to the improved electronic conductivity and suppressed particle aggregation during the conversion reaction. Voltage profile and cyclic voltammetry test results showed active material transformation in both anode materials during the cycling process. Furthermore, the infrared spectra at different discharge/charge states showed that the conversion reactions of MnCO 3 included not only the transition from MnCO 3 to Mn, but also a further reaction from Li 2 CO 3 to Li 2 O. [ABSTRACT FROM AUTHOR]

A novel facile strategy was developed to prepare the Fe 3 O 4 @graphene aerogel (Fe 3 O 4 @GA) composites. Fe 3 O 4 nanoparticles were uniformly dispersed into the 3D network of graphene aerogel and the resultant hybrid composites contained meso- and macro-scale pores with high specific surface area (276.9 m 2 g −1 ) and large pore volume (0.3230 cm 3 g –1 ). The electrochemical performance revealed that the Fe 3 O 4 @GA anode exhibited high reversible capacity (~941.5 mAh g −1 at a current density of 100 mA g −1 ), stable cycling performance, and excellent rate capability. [ABSTRACT FROM AUTHOR]

A novel air-stable titanium hexacyanoferrate (Ti 0.75 Fe 0.25 [Fe(CN) 6 ] 0.96 ·1.9H 2 O) with a cubic structure is synthesized simply by a solution precipitation method, which is first demonstrated to be a scalable, low-cost anode material for lithium-ion batteries exhibiting high capacity, long cycle life and good rate capability. Nevertheless, it has a low capacity of about 100 mAh g −1 as an anode material for sodium-ion batteries. [ABSTRACT FROM AUTHOR]

We report a facile process to synthesize Mo 0.91 W 0.09 S 2 /amorphous carbon composites with mean thickness of only 5 nm ultrathin nanosheets and their improved electrochemical performance as anode materials for lithium ion batteries (LIBs). Structural and morphological characterizations of the nanocomposite have been investigated by XRD, SEM and TEM. It was found the amorphous carbon to be well dispersed on the ultrathin nanosheets surface. Due to the increased interlayer distance and the synergistic effects between Mo 0.91 W 0.09 S 2 nanosheets and amorphous carbon, the as-prepared Mo 0.91 W 0.09 S 2 /C electrode deliveres exhibit a high Li capacity, an excellent rate capability, and a stable cycling performance, which suggests the Mo 0.91 W 0.09 S 2 /C composites as promising electrode material for LIBs. [ABSTRACT FROM AUTHOR]

Electrochemical performance of the 18650 lithium-ion batteries consisting lithium-rich layered oxides 0.5Li 2 MnO 3 ·0.5LiMn 0.33 Ni 0.33 Co 0.33 O 2 cathode material and soft carbon anode is investigated in detail. The cathode is synthesized by a spray drying process and the properties are studied by various methods, while the soft carbon is commercial available. The assembled batteries can exhibit excellent cyclic performance with a capacity retention of 90.2% even after 600 cycles in the voltage ranges of 2.0-4.5 V (at 1C-rate). Moreover, they can also deliver excellent rate capabilities as the discharge capacity under 40C is nearly equal to 83.9% of that under 1C (voltage range is in 2.0-4.5 V). Furthermore, in order to evaluate the mechanism of the superior performance exhibited by the full cells, cells after 300 cycles are disassembled in a glove box to assess the changes on the active materials by using a series of technique methods, including a scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), High-resolution transmission electron microscope (TEM) and selected area electron diffraction (SAED). [ABSTRACT FROM AUTHOR]

We simulate the electrochemical properties of Li-ion cells consisting of a blended cathode composed of LiMn 2 O 4 and LiNi 0.6 Co 0.2 Mn 0.2 O 2 and an artificial graphite anode using the Li-ion battery model available in COMSOL MULTIPHYSICS 4.4 along with a capacity fade model. The discharge profiles of the pure and blended cathodes at various current rates obtained through simulations and experimental results are well matched. By combining two capacity fade models available in literature, namely the solid electrolyte interphase (SEI) growth model and the Mn 2+ dissolution model, the cycling performance of the pure LiMn 2 O 4 cells at 25 °C are successfully simulated and found to be in a good agreement with the experimental results. The blended cathode exhibits better capacity retention than the pure LiMn 2 O 4 during cycling. We also observed that at high powers, the gravimetric energy density of the LiMn 2 O 4 cathode exceeds that of the LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode; the reverse effect is seen at low powers. Further, we were able to easily modulate the energy and power densities of the blended cathode system by changing the blend ratio in our simulation model. [ABSTRACT FROM AUTHOR]

Manganese dioxide/cabon nanotubes (MnO 2 /CNTs) composites with tunable density of MnO 2 nanosheets on the surface of CNTs were synthesized by a facile room temperature solution method. When applied in lithium-ion batteries (LIBs) as anode materials, the spacial density of MnO 2 nanosheets in the MnO 2 /CNT composite was verified to be crucial for the lithium storage performance. The optimized composite with moderate spatial density of MnO 2 nanosheets delivered a reversible capacity of 903 mA h g −1 at the current rate of 0.24 A g −1 . Moreover, this composite exhibited a high stable capacity of 540 mA h g −1 even at a high current density of 2.4 A g −1 after 1500 cycles, demonstrating its potential for applications in LIBs with long cycling life and high power density. The enhanced electrochemical performance of the optimized composite was ascribed to sufficient space between the MnO 2 nanosheets on the CNTs, which not only allows the effective electrical contact between the CNT backbones and the conductive carbon but also accommodates the large volume changes upon repeated lithiation/delithiation. [ABSTRACT FROM AUTHOR]

Transition metal oxides have been considered as promising lithium storage materials that undergo a conversion reaction, exhibiting high specific capacity. However, capacity fading during cycling is the most serious obstacle for their commercialization. In order to overcome this, we have added PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) to Mn 2 O 3 nanowires. PEDOT:PSS was successfully coated onto Mn 2 O 3 nanowires while maintaining the structure of Mn 2 O 3 . The coating of PEDOT:PSS reduced the resistance of the surface and protected the surface electron channels from the pulverization effect of the charge–discharge operation. α-Mn 2 O 3 /PEDOT:PSS showed excellent cyclability with a reversible capacity of 1450 mAh g −1 after 200 cycles at a current density of 100 mA g −1 . An increase in capacity was observed with continuous cycling, which may be attributed to further oxidation of the manganese species and a reversible reaction of the gel-like polymer on the manganese surface. The results demonstrate that PEDOT:PSS enhances the electrochemical activity by providing electron channels and prevents pulverization caused by the charge and discharge process. [ABSTRACT FROM AUTHOR]

Customized hierarchical porous metal oxide arrays is of great importance for construction of high-performance electrochemical devices. In this work, we report hierarchical porous (HP)-NiO sheets arrays by a facile hydrothermal method. Interestingly, the obtained NiO sheets arrays show HP systems, and are composed of cat-ear-like sheets main structure and interconnected nanosheets secondary structure. Moreover, the secondary nanosheets are highly porous and consist of cross-linked nanoparticles of 30–100 nm. The electrochemical performances of the HP-NiO sheets arrays are evaluated as anode for Li ion batteries. Compared with the normal NiO sheets arrays, enhanced electrochemical performances are achieved for the HP-NiO sheets, including higher capacity, better cycling life and high-rate capability. The HP-NiO sheets can deliver a specific capacity of 511 mAh g −1 at 3 A g −1 , higher than the normal NiO sheets arrays (374 mAh g −1 at 3 A g −1 ), due to the hierarchical porous array configuration with large surface area, fast ion diffusion path and better accommodation of volume change. [ABSTRACT FROM AUTHOR]

The internal distributed physicochemical characteristics of a battery significantly affect its performance. However, these properties are difficult to measure experimentally. This study presents a validated three-dimensional (3D) battery model covering the conservation of charge, mass, and energy and the electrochemical reaction of a laminated 10 Ah lithium iron phosphate battery. Using this 3D battery model, the space and time distributions of the internal physicochemical properties of the battery are investigated. The results indicate that the maximum gradients of the properties are at the transition region between the tabs and electrode plates. Thus, the tabs in a battery should be reasonably designed. For this LiFePO 4 /Graphite battery, anode plays a more important role than cathode in the overall overpotential and is likely to be crucial in the sharp decrease of output voltage at the later discharge process. And a higher battery capacity can be obtained by increasing the amount of anode material. [ABSTRACT FROM AUTHOR]

NiCr 2 O 4 is successfully prepared via hydrothermal pretreatment and subsequent sintering, which shows excellent electrochemical performance as a new anode material for lithium ion batteries with natural graphite adding and sodium alginate binder. At a specific current of 70 mA g −1 , it delivers charge and discharge capacities of 465.5 and 919.8 mAh g −1 in the initial cycle, which gradually increases along with cycle number owing to an electrochemical reconstruction in cycling. After 100 cycles, the charge and discharge capacities are 582.9 and 592.5 mAh g −1 , respectively. Furthermore, it is testified that natural graphite adding can effectively improve the electronic conductivity of the NiCr 2 O 4 electrode, and an appropriate amount of natural graphite is beneficial to improve the specific capacity and cycle stability of the electrode owing to a coordinated electrochemical reconstruction between NiCr 2 O 4 and natural graphite in cycling. [ABSTRACT FROM AUTHOR]

The peanut shells derived porous hard carbons (PSDHCs) by pyrolysis have been investigated as anodes of lithium/sodium batteries (LIBs/NIBs). Directly from the starting peanut shells, 600°C is found to be the favorable pyrolysis temperature for preparation of the PSDHC sample (PSDHC-600) with the best electrochemical performances for LIB applications. Furthermore, from the activated peanut shells in KOH solution, the produced PSDHC-600A by pyrolysis at 600°C is observed to offer greatly enhanced Li + /Na + ion storages. For LIB applications, PSDHC-600A delivers a retained capacity of 474 mAhg −1 after 400 cycles at 1 Ag −1 , larger than 314 mAhg −1 of PSDHC-600. At a high current rate of 5 Ag −1 , PSDHC-600A sustains over 10000 cycles with no obvious sign of fade in capacity, and a capacity of 310 mAhg −1 is still retained. For NIB applications, a capacity of 193 mAh g −1 is retained after 400 cycles at 0.25 Ag −1 , higher than 130 mAhg −1 of PSDHC-600. Even at 1 Ag −1 , PSDHC-600A can be stably cycled over 3000 cycles, and a capacity of 129 mAhg −1 is still retained. In comparison to PSDHC-600, the enhanced electrochemical properties of PSDHC-600A can be attributed to the finer porous structure with the increased percentage of nanoscale pores of diameter less than 2 nm and the larger specific surface area. [ABSTRACT FROM AUTHOR]

Silver with a high theoretical capacity for lithium storage is an attractive alloy based anode for Li-ion batteries, but large volume changes associated with AgLi x alloy formation leads to electrode cracking, pulverization and rapid capacity fading. A buffer matrix, like the electrospun hollow carbon nanofibers, can reduce this problem to a great extent. Herein, we demonstrate the facile synthesis of a free-standing, binder free Ag-C hybrid electrode through co-axial electrospinning, where well dispersed Ag nanoparticles are embedded in hollow carbon nanofibers. Using this approach, the long cycle life of carbon is complemented with the high lithium storage capacity of Ag, resulting in a high performance anode. The Ag-C composite electrode delivers a capacity of 739 mAh g −1 (>conventional graphite anodes) at 50 mA g −1 , with ∼85% capacity retention after 100 cycles. In addition, the Ag-C composite nanofibers are highly porous and exhibit a large accessible surface area (∼726.9 m 2 g −1 ) with an average pore diameter of ∼6.07 nm. The encapsulation of Ag in the hollow interiors not only provides additional lithium storage sites but also enhances the electronic conductivity, which combined with the reduced lithium diffusion path lengths in the nanofibers result in faster charge-discharge kinetics and hence a high rate performance. [ABSTRACT FROM AUTHOR]

CoV 2 O 6 /natural graphite electrode with sodium alginate binder is prepared, which shows excellent electrochemical performance as anode for Li-ion batteries. It exhibits initial discharge and charge capacity of 902 and 638 mAh g −1 at a specific current of 110 mA g −1 . After 100 cycles, the discharge and charge capacity maintain of 669 and 665 mAh g −1 , respectively. The charge/discharge mechanism of CoV 2 O 6 is also studied, suggesting a structure variation in discharging, which involves the initial formation of LiV 2 O 5 and Co 3 V 2 O 8 , the subsequent transition from Co 3 V 2 O 8 to Li x V 2 O 5 and CoO, and the later reduction of CoO into Co. The structure variation of Co 3 V 2 O 8 accompanies by an amorphization process, which maintains in the subsequent discharging and charging process. [ABSTRACT FROM AUTHOR]

Hierarchical assembly of hollow microstructures is of great scientificity and practical value. In this paper, a hydrothermal synthesis of Li 4 Ti 5 O 12 hollow microspheres assembled by nanosheets is introduced. Transmission electron microscopy (TEM) image shows that such Li 4 Ti 5 O 12 microspheres, with sizes of 2 μm in diameter, are composed of a hollow inner cavity and thin outer shell assembled by nanosheets. A possible growth mechanism of the structure is further expounded. The Li 4 Ti 5 O 12 hollow microspheres calcinated at 700 °C display extremely good electrochemical performance, including high capacity (147.3 mA h g −1 at 3 C), excellent cyclic stability (95.0% capacity retention after 100 cycles at 3 C) and remarkable rate capability (131.3 mA h g −1 at 20 C). [ABSTRACT FROM AUTHOR]

We have prepared two types TiO2(B)-carbon composites from Lepidocrocite-type compounds (K0.86Li0.26Ti1.72O4) heated at 700 and 900°C under presence of carbon nanotube (CNT) and glucose as carbon sources. The XRD data shows that it contains a single phase of TiO2(B) and the existence of carbon was confirmed by Raman spectra. TEM image confirms that TiO2(B) primary particles and carbon nanotube are scattered randomly and contact tightly in the composite. Carbon content in the composite was found to be 5 - 8% and CNT is the major carbonaceous material. The charge and discharge curves of TiO2(B)-carbon composite prepared from precursor heated at 700°C resemble with that of amorphous TiO2. The calculated discharge capacity of the composite is 323mAhg−1 at a cut off voltage of 0.9V, which is higher than that of bare TiO2(B). It is suggested that the electrochemical performance of this material is strongly influenced by both the operating temperature and cut off voltage. The discharge capacity can reach 198mAhg−1 at 4.5C rate at a cut off voltage 1.3V and the coulombic efficiency is over 99.8% after 10th cycles. [ABSTRACT FROM AUTHOR]

Hard carbon and microcrystalline graphite (MG) core-shell structured composite materials are prepared, and their electrochemical performances as an anode material for lithium-ion batteries are reported. The composite materials are obtained by coating a mixture of MG and pitch onto hard carbon particles, followed by heating at 1200 °C under an argon atmosphere for 1 h. The surface of the hard carbon is subsequently covered with a layer of the MG/pitch carbon composite. In the coating layer of the MG/pitch carbon composite, the MG particles are divided into nanoscale graphite sheets, and uniformly dispersed within the pitch of carbon matrix. The composite particles have a rounded shape, especially when the content of MG increases, which can improve their packing density compared to hard carbon having sharp edges. Anodes prepared from these composite materials exhibit enhanced electrochemical performances, including a high reversible capacity, high initial coulombic efficiency, high charging/discharging rate capability, and desirable cycling stability. [ABSTRACT FROM AUTHOR]

Abstract: Fe2O3-graphite (Fe2O3-G) composites have been facilely and effectively synthesized via ball milling. Structural features and electrochemical properties of the Fe2O3-G composites as anodes for lithium-ion batteries are investigated. The Fe2O3-G composites benefit from the close contact of nanocrystalline Fe2O3 with the graphite matrix, which improves the electronic conductivity and restrains the volume variation during cycling. The composite with 20% graphite shows the highest reversible capacity up to 491.1 mAh g−1 after 55 cycles with good rate capability. Due to the superior electrochemical performance, the Fe2O3-G composites prepared via ball milling could be promising as anode materials with high capacity, low-cost for lithium-ion batteries. [Copyright &y& Elsevier]

Abstract: Uniform Fe3O4/PPy composite nanospheres (FPCNs) with Fe3O4 nanoparticles embedded in PPy nanospheres (∼200nm) were prepared by a hydrothermal process followed by an ultrasonication assisted polymerization. For the first time, FPCNs were used as anode for lithium ion batteries, demonstrating enhanced electrochemical performance with high reversible capacity (544mAhg−1 after 300 cycles), remarkable capacity retention (98% of the initial capacity after 300 cycles), as well as good rate capability (332 mAh g−1 at 2000mAg−1). The spherical PPy matrix in FPCNs possesses three functions: 1) buffering the structural variation of Fe3O4 nanoparticles during charging/discharging process; 2) preventing the aggregation of Fe3O4 nanoparticles; 3) avoiding the direct contact between Fe3O4 nanoparticles and the electrolyte. The results observed in this study may shed some light on the investigation of MOx/polymer composite electrode materials. [Copyright &y& Elsevier]

Abstract: Undoped and 2 wt% vanadium (V5+) doped TiO2 samples are prepared in polyol medium by low-temperature solvothermal method. The as-prepared samples are annealed at 400 °C for 5 h in an air atmosphere to increase the crystallinity. The XRD pattern shows that pure anatase TiO2 is formed in both the doped and undoped samples. The maximum sizes of nanoparticles are found to be 300 nm and 15 nm with spherical shaped morphology for undoped TiO2 and V5+ doped TiO2 samples respectively. In addition, 2 wt% V5+ doped sample exhibits excellent electrochemical performance with high reversible specific capacity and excellent rate capability compared to the undoped case. This improvement can be attributed to the substitution of the Ti4+ ions by V5+ ions in the TiO2 lattice and create more Ti4+ vacancies in the lattice. This action may lead to the generation of apparently more number of free holes in the doped p-type semiconductor. Therefore, the increased hole concentration in the valence band can contribute to the electrical conductivity of the doped sample. Vanadium doping also influences the sample crystallinity and reduces the particle size, which provides a larger active surface area than that of undoped TiO2. [Copyright &y& Elsevier]

Highlights: [•] Polymer-derived SiCN and SiOC ceramics are studied as anode for Li-ion batteries. [•] Ceramic precursors are modified in order to increase the carbon content. [•] Ceramic matrix stabilizes free carbon phase. [•] Stabilizing role is lost once the amount of carbon exceeds a threshold value. [Copyright &y& Elsevier]

Abstract: The cobalt sulfides/graphene nanosheets (GNS) composite is prepared by a facile one-pot solvothermal route in the presence of graphene oxide sheets (GOS). XRD, SEM and TEM characterizations show that sphere-like cobalt sulfides particles with an average size of about 150 nm, which are complicated phases of CoS2, CoS and Co9S8, are highly dispersed on or wrapped in the creasy graphene. The selective nucleation and growth of cobalt sulfides particles on GOS make the particles more uniform in morphology and size. The as-fabricated cobalt sulfides/GNS composite exhibits very high electrochemical lithium storage reversible capacity of about 1018 mAh g−1. Moreover, the cobalt sulfides/GNS composite still remains reversible capacity of above 950 mAh g−1 after 50 cycles at a current density of 100 mA g−1 as well as at the different current densities from 100 to 1000 mA g−1, proving its excellent cycling durability and high-rate capability. The superior electrochemical performances of the composite may be attributed to the robust composite structure and superior conductivity, high charger mobility, large surface area and good flexibility of graphene. [Copyright &y& Elsevier]

Abstract: As an anode material for lithium-ion batteries (LIBs), silicon offers among the highest theoretical storage capacity, but is known to suffer from large structural changes and capacity fading during electrochemical cycling. Nanocomposites of silicon with carbon provide a potential material platform for resolving this problem. We report a spray-pyrolysis approach for synthesizing amorphous silicon–carbon nanocomposites from organic silane precursors. Elemental mapping shows that the amorphous silicon is uniformly dispersed in the carbon matrix. When evaluated as anode materials in LIBs, the materials exhibit highly, stable performance and excellent Coulombic efficiency for more than 150 charge discharge cycles at a charging rate of 1A/g. Post-mortem analysis indicates that the structure of the Si–C composite is retained after extended electrochemical cycling, confirming the hypothesis that better mechanical buffering is obtained when amorphous Si is embedded in a carbon matrix. [Copyright &y& Elsevier]

Summary: High energy lithium ion batteries are in demand for consumer electronics, electric-drive vehicles and grid-scale stationary energy storage. Si is of great interest since it has 10 times higher specific capacity than traditional carbon anodes. However, the poor cyclability due to the large volume change of Si upon insertion and extraction of lithium has been an impediment to its deployment. This review outlines three fundamental materials challenges associated with large volume change, and then shows how nanostructured materials design can successfully address these challenges. There have been three generations of nanostructure design, encompassing solid nanostructures such as nanowires, hollow nanostructures, and clamped hollow structures. The nanoscale design principles developed for Si can also be extended to other battery materials that undergo large volume changes. [ABSTRACT FROM AUTHOR]

Abstract: CoO–NiO–C nanocomposite materials with different morphology are successfully synthesized by using co-precipitation and subsequent pyrolytic carbon reduction method. The structure and morphology of obtained materials are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD patterns of samples display the diffraction peaks of 3CoO·5NiO cubic crystal. Moreover, the synthesis conditions which strongly impact on the morphology and electrochemical properties of the CoO–NiO–C materials are systematically investigated. When CoO–NiO–C materials are used as anodes for lithium ion batteries, the sample obtained at 600°C exhibits the best cycling performance, which shows a reversible capacity about 562mAhg−1 at the current density 100mAg−1 after 60 cycles. On the other hand, this material also exhibits a superior rate performance. The excellent performance of samples could be attributed to the small and uniform particle size and introducing of metal oxides composite structure, which could improve the kinetic behavior and accommodate the volume changes during cycling. [Copyright &y& Elsevier]

Abstract: A novel C/Co composite with Co nanoparticles embedded in carbon matrix is synthesized firstly by pyrolysis of polymeric cobalt phthalocyanine (PcCo) at 700°C in argon atmosphere. This composite is investigated as an anode material for lithium ion batteries, indicating high tap density and excellent electrochemical performance. The C/Co electrode can retain a higher reversible capacity of over 600mAhg−1 at a current of 50mAg−1 after 40cycles and shows better rate capability and less hysteresis in comparison to carbon not containing Co. The significant improvement is attributed to the Co nanoparticles grown in-situ reaction with catalytic activity and high electrical conductivity. [Copyright &y& Elsevier]

Abstract: Sn–Co alloy films are deposited electrochemically directly onto nickel foam in an aqueous solution. The influence of electrochemical current density and heat treatment on the structure and morphology of the electrodeposited films is studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical properties of the Sn–Co alloy films are further investigated by galvanostatic charge–discharge tests. As anodes for lithium ion batteries, the Sn–Co alloy-film anodes, after further heat treatment at 200°C for 30min, delivers a specific capacity of 663mAhg−1 after 60 cycles. This high capacity retention is attributed to the unique electrode configuration with an enhanced interface strength between the active material and the current collector formed in the heat-treatment process. [Copyright &y& Elsevier]

Abstract: Graphene nanosheets (GNSs) are prepared by oxidation and rapid expansion of graphite using microwave radiation. The prepared GNSs are characterized using various characterization tools. Morphological characterization using field emission scanning electron microscopy (FE-SEM) and transmission electron microscopic (TEM) studies revealed that the GNSs prepared through microwave radiation are crumbled with scrolled and entangled nature. Raman spectroscopy and X-ray diffraction (XRD) studies confirmed the graphitic crystalline structure of the synthesized GNSs. The surface composition and functional groups introduced on the surface of GNSs due to microwave radiation are corroborated using X-ray photoelectron spectroscopy (XPS) and Fourier transform Infrared Spectroscopy (FT-IR). Electrochemical characterization studies of GNSs based anode materials showed an enhanced lithium storage capacity and fine cycle performance. The initial discharge capacity of GNS electrode is 580mAhg−1 that decreases to 420mAhg−1 at 50th cycle. Electrochemical impedance spectral analysis reveals that the exchange current density of GNSs increases with the charge–discharge cycle numbers exhibiting the peculiar electrochemical performance. [Copyright &y& Elsevier]

Abstract: SnO x -embedded carbon nanofibers (SnO x /CNF) were synthesized by electrospinning a composite solution of Sn(II) acetate, polyacrylonitrile (PAN), and polyvinylpyrrolidone (PVP) in N,N-dimethylformamide (DMF), followed by stabilization and carbonization. The SnO x for SnO x /CNF-700 was distributed about below 2nm in diameter, whereas that for SnO x /CNF-800 represented around below 4nm. The fine structure of SnO x for SnO x /CNF was confirmed by analysis of extended X-ray absorption fine structure (EXAFS). The diameter of the fibers decreased with increasing temperature, whereas both SnO x particles and electrical conductivity of SnO x /CNF increased. Both SnO x /CNF-700 and SnO x /CNF-800 were prepared as disordered structures, whereas SnO x /CNF-900 was synthesized as an SnO2-like structure. The disordered transformation inducing excellent electrochemical performance originated form CNF prepared by electrospinning and proper heat treatment. Pure SnO2 displayed low electrochemical performance, indicating a typical large volume change and high mechanical stress. On the contrary, SnO x /CNF-800 represented outstanding specific discharge capacity and exceptional cycle retention at the same time, representing a coulomb efficiency of 71% even in the initial cycle. The specific discharge capacity for SnO x /CNF-800 slightly decreased by the 20th cycle, and then gradually increased by the 100th cycle. The CNF plays an important role as a buffering agent to prevent SnO x particles from agglomerating. The CNF having 1D pathway with high electrical conductivity leads to the promotion of charge transfer as well as mass transfer. [Copyright &y& Elsevier]

A nanocomposite of CeO2–graphene was prepared by a simple hydrothermal method and its electrochemical properties were investigated as a possible anode material for lithium ion batteries. Morphological characterization revealed that quasi-spherical CeO2 particles with a size of ∼100nm were dispersed randomly on the graphene matrix. The nanocomposite shows a greater capacity for reversal and a better performance rate than a bare CeO2 electrode. The better electrochemical performance could be attributed to the unique structure of the nanocomposite, which combines the conductive graphene network with dispersed CeO2 particles. [ABSTRACT FROM AUTHOR]

Abstract: A unique ordered mesoporous Sn–C composite with Sn nanoparticles confined in carbon nanorods was prepared using SBA-15 as the template. This composite was employed as the anode material of Li-ion batteries, delivering excellent electrochemical properties of high reversible lithium storage capacity (554 mAh g−1 after 200 cycles) and great rate capability (as high as 5000mA g−1). [Copyright &y& Elsevier]

Abstract: Li4Ti5O12 and Ru-doped Li4Ti5O12 with the formulation of Li4Ti4.99Ru0.01O12 were prepared by a modified solid-state method. The structure and electrochemical properties of the as-prepared powders were systematically investigated. Li4Ti4.99Ru0.01O12 exhibited an excellent rate capability with a discharge capacity of 146mAhg−1 at 1C, 126mAhg−1 at 5C, 119mAhg−1 at 10C and even 107mAhg−1 at 20C. Electrochemical impedance spectra (EIS) reveal that the Li4Ti4.99Ru0.01O12 exhibited the improved electronic conductivity and higher lithium-ion diffusivity than that of Li4Ti5O12. The novel Li4Ti4.99Ru0.01O12 material stands as a promising potentially high rate anode material for the lithium ion batteries. [Copyright &y& Elsevier]

Abstract: CuO/C microspheres are prepared by calcining CuCl2/resorcinol-formaldehyde (RF) gel in argon atmosphere followed by a subsequent oxidation process using H2O2 solution. The microstructure and morphology of materials are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transition electron microscopy (TEM). Carbon microspheres have an average diameter of about 2μm, and CuO particles with the sizes of 50–200nm disperse in these microspheres. The electrochemical properties of CuO/C microspheres as anode materials for lithium ion batteries are investigated by galvanostatic discharge–charge and cyclic voltammetry (CV) tests. The results show that CuO/C microspheres deliver discharge and charge capacities of 470 and 440mAhg−1 after 50 cycles, and they also exhibit better rate capability than that of pure CuO. It is believed that the carbon microspheres play an important role in their electrochemical properties. [Copyright &y& Elsevier]

Abstract: Thermodynamic calculation and kinetic analysis were performed on the carbothermal reduction process of Co3O4–Sb2O3–C system to clarify the reaction mechanism and synthesize pure CoSb powder for the anode material of secondary lithium-ion batteries. The addition of carbon amount and thus the purity of CoSb powders were critical to the electrochemical property of CoSb anode. It was revealed that in an inert atmosphere, Co3O4 was preferentially reduced to CoO, followed by the reduction of Sb2O3 and CoO. CO2 was the gas product for the reduction of Co3O4 and Sb2O3, while CO was the gas product for that of CoO. Based on the analysis result, pure CoSb powder without any oxides and residual carbon was synthesized, which showed a higher specific capacity and a lower initial irreversible capacity loss, compared to CoSb sample with residual carbon. This work can be a reference for other carbothermal reduction systems. [Copyright &y& Elsevier]

Carbon aerogels are nanostructure porous carbon materials that are derived via a sol—gel process with resorcinol and formaldehyde and subsequent pyrolysis of the precursor aerogels. Due to their high surface area, electrically conducting network, and chemical inertness, carbon aerogels can be considered ideal electrodes in rechargeable batteries. In this article, nanocomposite carbon anodes were prepared using carbon aerogels powders and graphite powders and the compound powders and binder, separately. With different carbon anodes and with lithium metal foil as the cathode, half-cells were made. Electrochemical measurements of the lithium intercalation properties for carbon aerogels were performed under high-purity argon in a glove box. The model cells showed that the initial charge capacity is 1135 mAh/g, and nanocomposite carbon anodes revealed better properties. This was due to the carbon aerogels’ electrically conducting network in order to provide good access of Li+ ions and electrons to active material. [ABSTRACT FROM PUBLISHER]

Abstract: Although a variety of cathode and electrolyte materials have been studied and commercialized over the past two decades, nearly all commercial cells have used a graphitic carbon anode. Several reasons exist for this choice—including cost, low insertion voltage, and ease of use in the cell manufacturing process. However as uses for lithium-ion batteries expand, alternative anodes that may offer better energy and power capability are being explored. For transportation-oriented purposes, anodes based on simple lithiated Zintl compounds, e.g. Li17Sn4, or intermetallic insertion anodes offer significant advantages in capacity (volumetric and gravimetric) and stability in the cell environment that make them attractive candidates for future cell chemistries. Within this context, little however is known about how these alternative anode materials perform as a function of temperature, which is important for applications where operation at temperatures as low as −30°C can be expected. In this study we evaluated a series of intermetallic insertion anodes that operate by a simple metal displacement mechanism. We have found that for Cu6Sn5, Ag/Cu6Sn5, and Cu2Sb, the drop-off in performance with temperature is in line with that observed for a commercial graphite-based anode and indicates that additional variables such as cation diffusion through the electrode passivation film or the electrochemical double layer may be playing an important role that is independent of the underlying anode material. We additionally characterized the NiAs-type mineral Sorosite (CuSn0.9Sb0.1), as various literature reports had indicated that substitution of antimony for tin eliminated the need for interstitial copper, however powder X-ray diffraction studies of samples made by annealing or high energy ball milling indicated mixed phase samples. [Copyright &y& Elsevier]

Abstract: A porous Li4Ti5O12 anode material was successfully synthesized from mixture of LiCl and TiCl4 with 70wt% oxalic acid by a modified one-step solid state method. The anode material Li4Ti5O12 exhibited a cubic spinel structure and only one voltage plateau occurred around 1.5V. The initial capacity of porous Li4Ti5O12 was 167 and 133mAhg−1 at 0.5 and 1C charge/discharge rate, respectively, and the capacity retention maintained above 98% after 200 cycles. The porous Li4Ti5O12 structure showed promising rate performance with a capacity of 70mAhg−1 at charge/discharge 10C rate after 200 cycles. It was demonstrated that the porous structure could withstand 50C charge/discharge rate and exhibited excellent cycling stability. [Copyright &y& Elsevier]

Abstract: NiO/Co–P nanocomposite is prepared by an electroless cobalt plating technique. The as-prepared composite is characterized by means of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. SEM and TEM images reveal that the NiO particles are about 200nm in size, which are modified by Co–P nanoparticles of about 30nm. The electrochemical properties as anode materials for lithium ion batteries are examined by cyclic voltammetry (CV) and discharge–charge tests. The results show that, compared with the bare NiO without electroless cobalt plating, NiO/Co–P nanocomposite exhibits a smaller polarization and a better rate capability, which is attributed to the Co–P nanoparticles. [ABSTRACT FROM AUTHOR]

Abstract: Porous nickel phosphide films are fabricated by electrodeposition through self-assembled polystyrene sphere multi-layers as template. After the removal of the template, well-ordered and close-packed spherical pores are left in the films. The thin walls of the adjacent pores make up a three-dimensional network nanostructure in the triple-layer porous Ni3P film. The as-prepared triple-layer porous film delivers significantly enhanced rate capability over the single- and double-layer ones. After 50 cycles, the capacity of the triple-layer Ni3P porous film still sustains 557mAhg−1 and 243mAhg−1 at a charge–discharge rate of 0.2C and 5C (1 C=388mAg−1), respectively. According to the analysis of electrochemical impedance spectrum (EIS), the improved electrochemical performance of the triple-layer film can be attributed to the fast migration of Li+ through surface-passivating layer and the facilitated charge transfer into Ni3P three-dimensional network nanostructure. [ABSTRACT FROM AUTHOR]

Abstract: Nano-sized Co–Sn alloys with a certain amount of Sn oxides used as potential anode materials for lithium ion batteries were synthesized by hydrothermal route. The effects of hydrothermal conditions and post annealing on the phase compositions and the electrochemical properties of synthesized powders were characterized by means of X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) with energy dispersive spectra (EDS) analysis and galvanostatic cycling tests. Prolonging the dwelling time at the same hydrothermal temperature can increase the content of Sn oxides, which will lead to a high initial irreversible capacity loss but a better cycling stability owing to the buffer effect of irreversible product Li2O. Heat-treatment can increase the crystallinity and cause the presence of a certain amount of inert CoSn component, which both have positive impact on the cycling stability of Co–Sn electrode. By comparison with the lithiation/delithiation processes of metal Sn, a two-step mechanism of CoSn2 alloy during cycling was confirmed. [ABSTRACT FROM AUTHOR]