Search

Lithium-ion battery (LIBs) applications using antimony (Sb) based anodes with high specific capacity and suitable operating voltage have showed tremendous potential. However, the large volume variation during electrochemical cycling limits their application. In this paper, M-Sb (M=Co, Ni) nanoparticles embedded in nitrogen doped carbon nanofibers have been prepared by an electrospinning method, 3D interconnected M-Sb@CN (NiSb@CN and Sb/CoSb 2 @CN) fiber composites are obtained finally. M-Sb nanoparticles are uniformly distributed in N-doped carbon nanofibers, which can prevent their direct exposure to the electrolyte. Compared with bare Sb-M and Sb-C binary electrodes, the M-Sb-C three-component composite electrodes show smaller volume change and stronger charge transport ability. The introduction of the transition metal (Co, Ni) not only serves as buffer substrate for volume change, but also regulates the properties of carbon fibers as a catalyst. High reversible capacities of 647.4 and 620.2 mA h g−1 of NiSb@CN and Sb/CoSb 2 @CN fiber composites can be maintained after 600 cycles at a current rate of 500 mA g−1. First principles calculation demonstrates that N-doping and the incorporation of transition metal M have favorable effect on the improved Li binding energy, offering a possibility for the material design of the high-performance LIBs. [ABSTRACT FROM AUTHOR]

Abstract: Pt/carbon composite nanofibers were prepared by electrodepositing Pt nanoparticles directly onto electrospun carbon nanofibers. The morphology and size of Pt nanoparticles were controlled by the electrodeposition time. The resulting Pt/carbon composite nanofibers were characterized by running cyclic voltammograms in 0.20M H2SO4 and 5.0mMK4[Fe(CN)6]+0.10M KCl solutions. The electrocatalytic activities of Pt/carbon composite nanofibers were measured by the oxidation of methanol. Results show that Pt/carbon composite nanofibers possess the properties of high active surface area and fast electron transfer rate, which lead to a good performance towards the electrocatalytic oxidation of methanol. It is also found that the Pt/carbon nanofiber electrode with a Pt loading of 0.170mgcm−2 has the highest activity. [Copyright &y& Elsevier]

It is crucial to design effective cathode catalysts for high performance of Li–O 2 batteries (LOBs). Herein, porous LaCo 0.6 Ni 0.4 O 3 nanofibers decorated with ultrafine Co 3 O 4 nanoparticles (Co 3 O 4 @LCN NFs) are designed and employed as cathode catalyst for LOBs. The X-ray photoelectron spectroscopy measurement results suggested that uniform dispreading of Co 3 O 4 nanoparticles on LCN NFs surface could largely increase the surface chemisorbed oxygen, resulting in enhanced catalytic activity. Furthermore, with the assistance of Co 3 O 4 nanoparticles, Co 3 O 4 @LCN NFs can significantly facilitate O 2 adsorption and diffusion, Li 2 O 2 nucleation/decomposition and the formation of tiny sheet-like Li 2 O 2 , thereby achieving a low charge overpotential. A high specific capacity of 11,288 mA h g−1, a low charge voltage plateau of 3.72 V at first cycle and excellent cycle stability of 116 cycles at 1000 mA g−1 are obtained for LOBs with Co 3 O 4 @LCN NFs. [ABSTRACT FROM AUTHOR]

• MoP@nitrogen-doped carbon nanofibers are synthesized via electrospinning and an in-situ carbothermic self-reduction. • The as-prepared nanofibers with uniformly distributed MoP nanoparticles are interconnected into a conductive network. • The unique structure alleviates pulverization of active material and enhances ion/charge-transfer for a high Li/Na storage. • Quantitative kinetics analysis confirms that the charge storage behavior is governed by pseudocapacitance. Transition metal phosphide anodes have received increasing attention for lithium/sodium-ion batteries due to their high theoretical capacities and apposite intercalation potential range. However, the mechanical stress induced dramatic volumetric expansion upon a conversion reaction mechanism has hindered the practical applications. Herein, we demonstrate a high performance anode of MoP@nitrogen-doped carbon nanofibers (MoP@NCNFs), which are prepared from an electrospinning method followed by an in-situ carbothermic self-reduction process. The well-crystallized MoP nanoparticles are uniformly distributed in the interweaving nanofibers, affording a conductive network for fast charge/ion transport and adequate buffer space for volumetric expansion. Benefit from the unique structure, the MoP@NCNFs synthesized at 800 °C delivers a reversible capacity of 840 mAh g−1 at 100 mA g−1 after 200 cycles. At 2 A g−1, longer cycling upto 1300 cycles is achieved with a capacity of 377 mAh g−1 along with a Coulombic efficiency of 99% for Li storage. And a decent performance is also available for sodium storage. Quantitative kinetics analysis confirms that the charge storage behavior is governed by pseudocapacitance, especially at high rates (75.9% at 1 mV s–1), boosting the high-rate lithium/sodium storage performance. Image, graphical abstract [ABSTRACT FROM AUTHOR]