Abstract
Conventional lithium-ion batteries embrace graphite anodes which operate at potential as low as metallic lithium, subjected to poor rate capability and safety issues. Among possible ...alternatives, oxides based on titanium redox couple, such as spinel Li
4
Ti
5
O
12
, have received renewed attention. Here we further expand the horizon to include a perovskite structured titanate La
0.5
Li
0.5
TiO
3
into this promising family of anode materials. With average potential of around 1.0 V vs. Li
+
/Li, this anode exhibits high specific capacity of 225 mA h g
−1
and sustains 3000 cycles involving a reversible phase transition. Without decrease the particle size from micro to nano scale, its rate performance has exceeded the nanostructured Li
4
Ti
5
O
12
. Further characterizations and calculations reveal that pseudocapacitance dictates the lithium storage process and the favorable ion and electronic transport is responsible for the rate enhancement. Our findings provide fresh impetus to the identification and development of titanium-based anode materials with desired electrochemical properties.
Fe3O4 has long been regarded as a promising anode material for lithium ion battery due to its high theoretical capacity, earth abundance, low cost, and nontoxic properties. However, up to now no ...effective and scalable method has been realized to overcome the bottleneck of poor cyclability and low rate capability. In this article, we report a bottom-up strategy assisted by atomic layer deposition to graft bicontinuous mesoporous nanostructure Fe3O4 onto three-dimensional graphene foams and directly use the composite as the lithium ion battery anode. This electrode exhibits high reversible capacity and fast charging and discharging capability. A high capacity of 785 mAh/g is achieved at 1C rate and is maintained without decay up to 500 cycles. Moreover, the rate of up to 60C is also demonstrated, rendering a fast discharge potential. To our knowledge, this is the best reported rate performance for Fe3O4 in lithium ion battery to date.
A novel and facile two-step strategy has been designed to prepare high performance bi-transition-metals (Fe- and Mo-) carbide supported on nitrogen-doped graphene (FeMo-NG) as electrocatalysts for ...oxygen reduction reactions (ORR). The as-synthesized FeMo carbide -NG catalysts exhibit excellent electrocatalytic activities for ORR in alkaline solution, with high onset potential (-0.09 V vs. saturated KCl Ag/AgCl), nearly four electron transfer number (nearly 4) and high kinetic-limiting current density (up to 3.5 mA cm(-2) at -0.8 V vs. Ag/AgCl). Furthermore, FeMo carbide -NG composites show good cycle stability and much better toxicity tolerance durability than the commercial Pt/C catalyst, paving their application in high-performance fuel cell and lithium-air batteries.
In this paper, using Ni3S2@MoS2 as an example, we report the successful design and synthesis of a novel hybrid core/shell metal sulfides with a conductive Ni3S2 core by a green, scalable and one-step ...solution strategy. When they are tested as supercapacitor electrodes, the Ni3S2@MoS2 heterostructure exhibits about 2 times the capacitance (848Fg−1) compared to the pristine Ni3S2 sample (425Fg−1), excellent rate capability (46.6% capacity retention at 20Ag−1) and outstanding cycling stability (91% retention after 2000 cycles). The enhancement is ascribed to the robust hierarchical core/shell structures which provide an increased reaction area and a close contact of electrolyte with the active material. In addition, a highly conductive 1D core material endows the quick transport of electrons along Ni3S2 nanorods to Ni foam. It is prospected that such novel hybrids can offer great potential promise in large-scale energy storage device applications.
One-dimensional hierarchical Ni3S2@MoS2 core/shell nanorod arrays on Ni foam synthesized using a one-step hydrothermal method exhibit a higher specific capacitance with better cycling performance than bare Ni3S2 sample. Display omitted
•A facile but powerful method is designed to grow Ni3S2@MoS2 core/shell nanoarrays on Ni foam.•Ni3S2@MoS2 heterostructure exhibits better performance than bare Ni3S2 sample.•Such novel hybrids can offer great potential promise in large-scale energy storage applications.
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