Restacked MoS(2) with enlarged c lattice parameter and surface area was prepared by exfoliation and restacking process, exhibiting high reversible lithium storage capacity and superior rate capability as anode material for lithium ion batteries.

Lithium-ion batteries power many portable devices and in the future are likely to play a significant role in sustainable-energy systems for transportation and the electrical grid. LiFePO(4) is a candidate cathode material for second-generation lithium-ion batteries, bringing a high rate capability to this technology. LiFePO(4) functions as a cathode where delithiation occurs via either a solid-solution or a two-phase mechanism, the pathway taken being influenced by sample preparation and electrochemical conditions. The details of the delithiation pathway and the relationship between the two-phase and solid-solution reactions remain controversial. Here we report, using real-time in situ neutron powder diffraction, the simultaneous occurrence of solid-solution and two-phase reactions after deep discharge in nonequilibrium conditions. This work is an example of the experimental investigation of nonequilibrium states in a commercially available LiFePO(4) cathode and reveals the concurrent occurrence of and transition between the solid-solution and two-phase reactions.

Very large area, uniform TiO 2 @carbon composite nanofibers were easily prepared by thermal pyrolysis and oxidization of electrospun titanium(IV) isopropoxide/polyacrylonitrile (PAN) nanofibers in argon. The composite nanostructures exhibit the unique feature of having TiO 2 nanocrystals encapsulated inside a porous carbon matrix. The unique orderly-bonded nanostructure, porous characteristics, and highly conductive carbon matrix favour excellent electrochemical performance of the TiO 2 @carbon nanofiber electrode. The TiO 2 @carbon hybrid nanofibers exhibited highly reversible capacity of 206 mAh g À1 up to 100 cycles at current density of 30 mA g À1 and excellent cycling stability, indicating that the composite is a promising anode candidate for Li-ion batteries.

Li-ion batteries are the power source of choice for most portable electronic devices and are promising energy-storage candidates for electric vehicles and renewable energy systems. [ 1 ] To realize their use in these further applications, Li-ion battery technology needs to be improved to provide more power, be safer to use, have longer cycle life, and become cheaper to produce. [ 2 , 3 ] This study focuses on anode materials, the commercial market for which is dominated by graphite-based anode materials, which are susceptible to plating of their surface by Li and to the formation of a solid-electrolyte interface (SEI) layer that can reduce battery safety and capacity. [ 4 ] An alternative to graphite-based anodes are metal oxides; however, to meet the performance of graphite-based anodes, it is necessary to reduce the particle size of the metal oxides to increase their specifi c charge. Particular interest lies in the so-called low-voltage oxides, such as TiO 2 since they are relatively safe compared to Li, Li alloys, and graphite. [ 5 ] These lowvoltage oxides are being developed for specialized applications, such as for microelectronics and consumer devices that feature photovoltaic recharging. [ 6 ] The two titania polymorphs (anatase and rutile) and the spinel Li 4 Ti 5 O 12 have Li-intercalation potentials of about 1.78 V and 1.56 V vs Li + /Li, respectively. [ 7 , 8 ] The operating voltages for anodes composed of these materials are relatively high compared to graphite, which is 0.1-0.2 V vs Li + /Li, [ 5 ]

Modulation of material physical and chemical properties through selective surface engineering is currently one of the most active research fields, aimed at optimizing functional performance for applications. The activity of exposed crystal planes determines the catalytic, sensory, photocatalytic, and electrochemical behavior of a material. In the research on nanomagnets, it opens up new perspectives in the fields of nanoelectronics, spintronics, and quantum computation. Herein, we demonstrate controllable magnetic modulation of α-MnO2 nanowires, which displayed surface ferromagnetism or antiferromagnetism, depending on the exposed plane. First-principles density functional theory calculations confirm that both Mn- and O-terminated α-MnO2 (1 1 0) surfaces exhibit ferromagnetic ordering. The investigation of surface-controlled magnetic particles will lead to significant progress in our fundamental understanding of functional aspects of magnetism on the nanoscale, facilitating rational design of nanomagnets. Moreover, we approved that the facet engineering pave the way on designing semiconductors possessing unique properties for novel energy applications, owing to that the bandgap and the electronic transport of the semiconductor can be tailored via exposed surface modulations.

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Pristine and boron-doped anatase TiO2 were prepared via a facile sol-gel method and the hydrothermal method for application as anode materials in sodium-ion batteries (SIBs). The sol-gel method leads to agglomerated TiO2, whereas the hydrothermal method is conducive to the formation of highly crystalline and discrete nanoparticles. The structure, morphology, and electrochemical properties were studied. The crystal size of TiO2 with boron doping is smaller than that of the nondoped crystals, which indicates that the addition of boron can inhibit the crystal growth. The electrochemical measurements demonstrated that the reversible capacity of the B-doped TiO2 is higher than that for the pristine sample. B-doping also effectively enhances the rate performance. The capacity of the B-doped TiO2 could reach 150 mAh/g at the high current rate of 2C and the capacity decay is only about 8 mAh/g over 400 cycles. The remarkable performance could be attributed to the lattice expansion resulting from B doping and the shortened Li(+) diffusion distance due to the nanosize. These results indicate that B-doped TiO2 can be a good candidate for SIBs.