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Ferroferric oxide (Fe3O4) is regarded to be a promising high-capacity anode material for LIBs. However, the capacity attenuates fast and the rate performance is poor due to the dramatic pulverization and sluggish charge transfer properties. To solve these problems, a simple in situ encapsulation and composite method was successfully developed to construct carbon nanotube/nanorod/nanosheet-supported Fe3O4 nanoparticles. Owing to the hierarchical architecture design, the novel structure Fe3O4@C nanocomposites effectively enhance the charge transfer, alleviate pulverization, avoid the agglomeration of Fe3O4 nanoparticles, and also provide superior kinetics toward lithium storage, thereby showing significantly improved reversibility and rate performance. The carbon nanotube/nanorod supported core-shell structure Fe3O4@C nanocomposite displays outstanding high rate capability and stable cycling performance (reversible capability of 1006, 552 and 423 mA h g−1 at 0.2, 0.5 and 1 A g−1 after running 100, 300 and 500 cycles, respectively). [ABSTRACT FROM AUTHOR]

Sheet-like lithium-rich cathode materials Li 1.2 Mn 0.54 Ni 0.16 Co 0.10 O 2 (LMNCO) assembled by primary grains of 100–500 nm in sizes were facilely prepared by a glucose-urea bubbling and post-annealing process. The post-annealing temperature was found to play an important role on the grain size, crystallinity, cation ordering and electrochemical performance of the cathode materials. The sample post-annealed at 900 °C showed larger grains, higher crystallinity, better layered structure, higher lithium storage capacity and better rate performance than the one annealed at 800 °C. An initial discharge capacity of above 300 mA h g −1 was obtained at 0.1 C (20 mA g −1 ) for the sample annealed at 900 °C, and at 1, 2, 5 and 10 C, discharge papacies of 223, 192, 157 and 128 mA h g −1 were achieved respectively. The material synthesizing process proposed in this study may be extended to prepare a wide range of sheet-like functional oxides that may be potentially applied in energy storage or other fields. [ABSTRACT FROM AUTHOR]

A flexible, free-standing composite anode with Li 4 Ti 5 O 12 nanosheet arrays anchoring on plain-weaved carbon fiber cloth (LTO@CC) is prepared by a hydrothermal and post-annealing process assisted by a TiO 2 seed layer. The LTO@CC anode free from polymeric binder and conducting agent exhibited much higher lithium storage capacity and cycling stability than the conventional slurry-processed electrode using the dandelion-like Li 4 Ti 5 O 12 microspheres prepared by the same hydrothermal process. A high specific capacity of 128.8 mA h g −1 was obtained at a current rate of 30 C (1 C = 175 mA g −1 ), and almost negligible capacity loses was observed when the cell was cycled at 10, 20 and 30 C each for 100 cycles. The carbon fiber matrix contributed to Li storage at low current rate, but the LTO nanosheet arrays have played the dominant role on the excellent rate capability. The improved electrochemical performance can be attributed to the synergetic effect between the hierarchical Li 4 Ti 5 O 12 nanosheet arrays and the carbon fiber matrix, which integrated short Li + diffusion length, three-dimensional conductive architecture and well preserved structural integrity during the high rate and repeated charge-discharge measurements. [ABSTRACT FROM AUTHOR]

Nitrogen-doped carbon-coated Li 4 Ti 5 O 12 -TiO 2 (LTO-TO) hybrid microspheres were prepared by heat treating the dry mixture of urea and chemically lithiated dandelion-like TiO 2 microspheres in a stainless steel autoclave at 550 °C for 5 h. The hybrid materials were tested as anode of Li-ion batteries. As compared to the pristine sample, the N-doped carbon-coated LTO-TO microspheres exhibited higher specific capacity at both low and high current rates. Discharge capacities of 184 and 123 mAh g −1 were obtained at 0.2 C and 20 C, respectively. Moreover, the LTO-TO/C electrode showed excellent cycle performance, with a discharge capacity of 121.3 mAh g −1 remained after 300 cycles at 5 C, corresponding to an average capacity degradation rate of 0.073% per cycle. These high specific capacity, excellent rate capability and cycle performance demonstrated the high potentiality of the N-doped carbon-coated LTO-TO microspheres as anode material of both energy storage-type and power-type Li-ion batteries. [ABSTRACT FROM AUTHOR]

Hierarchical nitrogen-doped carbon spheres (NCSs) prepared by annealing the MnO 2 -templated spherical polypyrrole (PPy) at 450 or 600 °C were tested as anode materials of Li-ion batteries. The NCSs annealed at 450 °C exhibited higher nitrogen content, more amorphous carbon structure, and lower surface area as compared to the sample annealed at 600 °C. The specific capacities and rate performances of both NCSs samples were much higher than that of commercial mesocarbon microbeads (MCMBs). The NCSs annealed at 600 °C exhibited higher capacity at low current density (<0.5 A g −1 ) but more rapid capacity decay at elevated current rates referring to the sample annealed at 450 °C. The NCSs annealed at higher temperature also possessed inferior cycling stability, possibly due to its lower electronic conductivity and higher degree of graphitization. A high specific capacity of 250.8 mAh g −1 was achieved on the NCSs annealed at 450 °C at 3 A g −1 , demonstrating their high potentiality as anode of high power Li-ion batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Graphite (MCMB) granulates were decorated with oxygen-deficient Nb 2 O 5-x nanoparticle. • The MCMB/Nb 2 O 5-x composite electrodes show much enhanced Li+ diffusion coefficient. • The composite electrodes exhibit better rate and cycle performances than pristine MCMB. • The Nb 2 O 5-x undergoes phase transition from crystalline to amorphous with formation of NbO. • The current-sharing effect of the secondary particles may help to improve the rate performance. Nanosized oxygen-deficient orthorhombic niobium pentoxide (Nb 2 O 5-x) that possess high electronic conductivity and stable cycle performance for Li storage are uniformly deposited on the surface of mesophase carbon microspheres (MCMB), which as a whole exhibits very encouraging electrochemical Li ion storage performance, including a high specific capacity of 107 mAh g−1 at 10C (1C = 372 mA g−1) and a high capacity retention of 85.4 % after 300 cycles at 3C in the optimized case. The Li+ diffusion coefficient of the composite anode as determined by the potentiostatic intermittent titration technique (PITT) is obviously improved as compared to that of pristine MCMB. Ex situ X-ray diffraction characterizations confirm the phase transformation from orthorhombic Nb 2 O 5-x to amorphous Li y Nb 2 O 5-x accompanied by the formation of NbO through a conversion reaction in the first lithiation process. The ultrafast Li+ diffusion within the amorphous Li y Nb 2 O 5-x as well as the current-sharing effect of the secondary particles can explain the much enhanced Li ion storage property. The results of this work convincingly demonstrate that designing MCMB/Nb 2 O 5-x composite can be a more practical way to improve the energy and powder densities of Li-ion batteries rather than seeking alternative anode materials with higher capacities. [ABSTRACT FROM AUTHOR]

Manganese monoxide (MnO) has been widely studied as a potential anode material of Li-ion batteries because of its high specific capacity and abundant raw materials. However, the poor cycling stability of MnO associating to its large volume change during the repeated conversion reaction with Li+ has restricted its practical applications. Herein, ternary MnO/MnTiO 3 @C composite anode materials are prepared by in situ capturing TiO 2 nanoparticles into sea urchin-like MnO 2 in a mild hydrothermal reaction, followed by resorcinol-formaldehyde (RF) resin coating and thermal treatment. With the strong stabilization effect of the MnTiO 3 component, the optimized ternary MnO/MnTiO 3 @C composite anode exhibits greatly enhanced cycling performance as compared to MnO@C. A reversible capacity of 383 mAh g−1 is preserved after 500 cycles at 1000 mA g−1. This improved cycle performance can be originated from the stable TiO crystals and the highly reversible amorphous Li x MnTiO 3 phase generated in the first lithiation process. The reasonably high specific capacity and robust cycle stability enable the ternary MnO/MnTiO 3 @C composites to be promising alternative anode materials to graphite for Li-ion batteries. [ABSTRACT FROM AUTHOR]

Abstract: Spinel lithium titanate, Li4Ti5O12, with novel hollow-sphere structure was fabricated by a sol–gel process using carbon sphere as template. The effect of the hollow-sphere structure as well as the wall thickness on the Li storage capability and high rate performance was electrochemically evaluated. High specific capacity, especially better high rate performance was achieved with this Li4Ti5O12 hollow-sphere electrode material with thin wall thickness. It is believed that this macroporous hollow-sphere structure has shortened the Li diffusion distance, increased the contact area between Li4Ti5O12 and electrolyte, and also led to better mixing of the active material with AB. All these factors have resulted in the good rate capability of the hollow-sphere structured Li4Ti5O12 electrode material. [Copyright &y& Elsevier]

Conductive carbon additives play very important roles on the performance of Li-ion batteries (LIBs) although they only occupy a very small mass percentage in both cathode and anode. Building up a multidimensional carbonaceous conductive network on cathode with the optimized mass ratio of carbon black, carbon nanotubes (CNTs) and graphene has been verified to be able to enhance the Li-ion storage performance. Herein, we further demonstrate that applying ternary conductive additives is also very effective in improving the rate and cycle performances of graphite anode although the active material already possess high electronic conductivity. A conductive additive assembly of 2 wt% Super P, 1 wt% CNTs and 1 wt% graphene can weave up an efficient conducting pathway on the mesocarbon microbeads (MCMB) anode and enhance the cycle stability (344 mAh g−1 at 1 C after 200 cycles) and rate performance (226 mAh g−1 at 3 C). The coin-type full cell assembled with the optimized MCMB anode and NCM811 cathode also displays much improved rate capability and cycle stability. As is revealed, the multidimensional conducting network might has led to a more uniform and ion conductive SEI film on MCMB anode, which lowers the polarization and energy barrier for Li+ transportation. [Display omitted] • A multidimensional conducting network is constructed on MCMB anode by modifying the dispersion solvent. • A specific capacity of 344 mAh g−1 is preserved after 200 cycles at 1 C. • The multidimensional conducting network promotes the Li+ transfer in MCMB anode. • Using ternary conductive additives in graphite anode is a practical way to improve the performance of LIBs. [ABSTRACT FROM AUTHOR]

Deriving carbon electrode materials from biomass resources has been the ongoing research interest for sustainable development of high performance electrochemical energy storage devices. Herein, navel orange peel is used as an abundant raw material to prepare hard carbon anodes for Na and Li-ion batteries through a two-step process. The hydrothermal treatment effectively decomposes the biomass into uniform precursor, while the following high temperature carbonization results in fine hard carbon particles. The hard carbon carbonized at 1300 °C exhibits the best Na ion storage performance including a high initial reversible capacity of 337 mAh g−1 at 0.1 A g−1 and a high remaining capacity of 234 mAh g−1 after 500 cycles at 0.5 A g−1, which can be explained by its featured structure favoring the adsorption-intercalation/filling model. The hard carbon pyrolized at 1100 °C displays a much higher reversible capacity of 428 mAh g−1 than many other biomass-derived hard carbon anodes together with a robust cycle stability. These outstanding Na and Li ion storage properties convincingly demonstrate that the two-step process as well as the abundant navel orange peel resource can provide a potential solution to sustainable development of high performance hard carbon anode materials for Na and Li-ion batteries. [Display omitted] • Hard carbons with uniform particle sizes are prepared from navel orange peel. • Very high Na-ion storage capacity of 337 mAh g−1 is obtained at 0.1 A g−1. • High capacity of 428 mAh g−1 is achieved from the hard carbon pyrolized at 1100 °C. • The abundant navel orange peel promises potential application of the hard carbons. [ABSTRACT FROM AUTHOR]

[Display omitted] • SiO is modified with Nb 2 O 5 and N-doped carbon coating before mixing with graphite. • The SiO@Nb 2 O 5 @NC anode shows much enhanced cycle and rate performance. • The decoration of capacitive Nb 2 O 5 is responsible for the enhanced properties. • A low cost while high performance SiO@Nb 2 O 5 @NC/SG composite anode is reported. Although SiO/G (G denotes graphite) products are commercially available in nowadays, their scalable applications in Li-ion batteries are still limited by their poor stability and high cost. Herein, niobium oxide (Nb 2 O 5) with open tunnel structure is composited with SiO in combination with N-doped carbon (NC) coating, which have jointly enhanced the rate and cycle performance of the resulting SiO@Nb 2 O 5 @NC composite anodes. Under optimum conditions, a capacity retention of 74% is preserved after 200 cycles at 0.2 A g−1, together with a high capacity of 666 mA h g−1 at 3 A g−1. Ex situ XRD analysis reveals that Nb 2 O 5 is transformed to amorphous Li x Nb 2 O 5 and electrochemical-inert NbO in the first lithiation process. The former exhibits fast Li+ migration rate and capacitive Li ion storage behavior, which may help to improve the electrochemical performance of SiO. Further mixing the SiO@Nb 2 O 5 @NC composite with spent graphite extracted from used LiFePO 4 battery yields a high capacity and stable anode material that shows a high capacity retention of 79% after 500 cycles at 0.4 A g−1. This work may shed a light on the development of stable yet low cost SiO/G anode materials through pre-modification of SiO with Nb 2 O 5 and utilization of cheap graphite resource. [ABSTRACT FROM AUTHOR]

• The large size Co9S8@C nanosheets were prepared by introducing Co9S8-DETA (DETA=Diethylenetriamine) as the precursor. • The 2D lamellar structure significantly reduce ions diffusion path in the Co9S8@C electrode to improve the diffusion kinetics. • The Co9S8@C exhibit outstanding lithium storage than Co9S8 nanosheets, due to the amorphous carbon shells configuration. The cobalt sulfides have become the focus materials on the lithium ion batteries application in which the Co 9 S 8 with the nanosheet structure is the promising candidate for anode material in high-energy and high-power lithium ion batteries. By introducing a novel strategy with the organic-inorganic hybrid Co 9 S 8 -DETA (DETA=Diethylenetriamine) as the precursor, the large size Co 9 S 8 @C nanosheets have been successfully prepared via a calcination process. Due to uniform two-dimensional structure of Co 9 S 8 and the amorphous carbon layer coating, the as-prepared Co 9 S 8 @C nanosheets exhibited excellent lithium ion storage performance as an anode material. The reversible capacity could be retained at 595 mAh g−1 after 160 cycles at 0.2 A g−1. The excellent performances of this nanocomposite offer numerous opportunities for other sulfides as a new anode in lithium ion batteries. [ABSTRACT FROM AUTHOR]