Facile co-precipitated synthesis of NdFeO3 perovskite nanoparticles for lithium-ion battery anodes

In this report, NdFeO₃ perovskite nanoparticles were facilely prepared by co-precipitation of Nd³⁺ and Fe³⁺ cations in hot water, followed with the pyrolysis process in atmospheric conditions. Morphology and crystal structure of NdFeO₃ perovskite were determined with appropriate methods, revealing orthorhombic lattice with size distribution from 40 to 180 nm. Functioning as anode lithium-ion batteries (LIBs), NdFeO₃ exhibited great electrochemical performance such as high retention capacity, excellent cyclability, and high current rate. Such enhanced electrochemical efficiency was evidently ascribed to the perovskite structure of NdFeO₃ due to short lithium-ion diffusion pathway and volume expansion control of working material during lithiation/delithiation operation. By demonstrating a capacity value of 475 mAh g^?1 even through 450 cycles at 0.1 A g^?1, NdFeO₃ perovskite nanoparticles proved itself a competitive anode material for the coming generations of LIBs. In addition, this novel synthesis method is suitable for mass production of perovskite materials for long-life lithium-storage facilities.

     

CoP nanoparticles enwrapped in N-doped carbon nanotubes for high performance lithium-ion battery anodes

CoP is a candidate lithium storage material for its high theoretical capacity. However, large volume variations during the cycling processes haunted its application. In this work, a four-step strategy was developed to synthesize N-doped carbon nanotubes wrapping CoP nanoparticles (CoP@N-CNTs). Integration of nanosized particles and hollow-doped CNTs render the as-prepared CoP@N-CNTs excellent cycling stability with a reversible charge capacity of 648 mA·h·g⁻¹ at 0.2 C after 100 cycles. The present strategy has potential application in the synthesis of phosphide enwrapped in carbon nanotube composites which have potential application in lithium-ion storage and energy conversion.     

Amorphous Sn modified nitrogen-doped porous carbon nanosheets with rapid capacitive mechanism for high-capacity and fast-charging lithium-ion batteries

Sn-based materials are considered as a kind of potential anode materials for lithium-ion batteries (LIBs) owing to their high theoretical capacity. However, their use is limited by large volume expansion deriving from the lithiation/delithiation process. In this work, amorphous Sn modified nitrogen-doped porous carbon nanosheets (ASn-NPCNs) are obtained. The synergistic effect of amorphous Sn and high edge-nitrogen-doped level porous carbon nanosheets provides ASn-NPCNs with multiple advantages containing abundant defect sites, high specific surface area (214.9 m²·g⁻¹), and rich hierarchical pores, which can promote the lithium-ion storage. Serving as the LIB anode, the as-prepared ASn-NPCNs-750 electrode exhibits an ultrahigh capacity of 1643 mAh·g⁻¹ at 0.1 A·g⁻¹, ultrafast rate performance of 490 mAh·g⁻¹ at 10 A·g⁻¹, and superior long-term cycling performance of 988 mAh·g⁻¹ at 1 A·g⁻¹ after 2000 cycles with a capacity retention of 98.9%. Furthermore, the in-depth electrochemical kinetic test confirms that the ultrahigh-capacity and fast-charging performance of the ASn-NPCNs-750 electrode is ascribed to the rapid capacitive mechanism. These impressive results indicate that ASn-NPCNs-750 can be a potential anode material for high-capacity and fast-charging LIBs.     

Robust 3D network architectures of MnO nanoparticles bridged by ultrathin graphitic carbon for high-performance lithium-ion battery anodes

Nano Research - A strategy was developed to fabricate a set of MnO@C nanohybrids with MnO nanoparticles (NPs) embedded in an ultrathin three-dimensional (3D) carbon framework for use as anode...     

Exploiting oleic acid to prepare two-dimensional assembly of Si@graphitic carbon yolk-shell nanoparticles for lithium-ion battery anodes

Carbon coating has been a routine strategy for improving the performance of Si-based anode materials for lithium-ion batteries. The ability to tailor the thickness, homogeneity and graphitization degree of carbon-coating layers is essential for addressing issues that hamper the real applications of Si anodes. Herein, we report the construction of two-dimensional (2D) assemblies of interconnected Si@graphitic carbon yolk-shell nanoparticles (2D-Si@gC) from commercial Si powders by exploiting oleic acid (OA). The OA molecules act as both the surface-coating ligands for facilitating 2D nanoparticle assembly and the precursor for forming uniform and conformal graphitic shells as thin as 4 nm. The as-prepared 2D-Si@gC with rationally designed void space exhibits excellent rate capability and cycling stability when used as anode materials for lithium-ion batteries, delivering a capacity of 1,150 mAh·g⁻¹ at an ultrahigh current density of 10 A·g⁻¹ and maintaining a stabilized capacity of 1,275 mAh·g⁻¹ after 200 cycles at 4 A·g⁻¹. The formation of yolk-shell nanoparticles confines the deposition of solid electrolyte interphase (SEI) onto the outer carbon shell, while simultaneously providing sufficient space for volumetric expansion of Si nanoparticles. These attributes effectively mitigate the thickness variations of the entire electrode during repeated lithiation and delithiation, which combined with the unique 2D architecture and interconnected graphitic carbon shells of 2D-Si@gC contributes to its superior rate capability and cycling performance.

     

One-step preparation of six-armed Fe3O4 dendrites with carbon coating applicable for anode material of lithium-ion battery

Six-armed Fe₃O₄ dendrites with carbon coating were synthesized by a simple one-step reaction between ferrocene and urea at 550 °C. Electron microscopy examinations indicate the formation of large numbers of Fe₃O₄ dendrites with mutually vertical arms and uniform carbon shells. Electrochemical measurement demonstrates that the dendrites using as anode materials for lithium-ion battery exhibit an initial capacity of 658 mAh g^? 1 and a reversible capacity of 473 mAh g^? 1 after 100 cycles at a rate of C/10, as well as a high cycling efficiency of 97% after the forth cycle. The formation mechanism of the six-armed dendrites was also discussed.     

Electrosprayed porous Fe3O4/carbon microspheres as anode materials for high-performance lithium-ion batteries

Nano Research - Porous Fe3O4/carbon microspheres (PFCMs) were successfully fabricated via a facile electrospray method and subsequent heat treatment, using ferrous acetylacetonate, carbon nanotubes...     

碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能研究

以二茂铁为铁源,石油渣油为碳源,通过加压热解和空气氧化制备了碳包覆空心Fe3O4纳米粒子。采用X射线衍射(XRD)、透射电镜(TEM)以及高倍透射电镜(HRTEM)等测试方法对样品的形貌和结构进行表征。采用恒流充放电和交流阻抗方法测试碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能。在电流密度为0.2mA/cm2时,首次放电比容量高达1294.7mAh/g,30次循环之后其放电比容量为392.1mAh/g;电流密度为1mA/cm2时,首次放电比容量为216.3mAh/g,30次循环之后其放电比容量为113mAh/g。     

中空海胆状结构的碳包覆Fe2O3用作锂离子电池的高性能负极材料

Fe2O3由于成本低廉,储量丰富和理论比容量高(1007 mA hg^-1)等特点,在锂离子电池负极材料的应用中极具发展前景.然而一些问题仍然存在,如:充放电过程中比容量的迅速衰减,不可逆的体积膨胀以及较短的循环寿命等.这些问题严重制约了Fe2O3在锂离子电池中的实际应用.为了突破这些局限,本文以金属-有机骨架(MOF...     

Binder-free,self-standing films of iron oxide nanoparticles deposited on ionic liquid functionalized carbon nanotubes for lithium-ion battery anodes

We report in-situ synthesis and direct deposition of Fe₂O₃ nanoparticles (NPs) on the ionic liquid (IL)-functionalized carbon nanotubes (fCNT). As shown in transmission electron microscope (TEM) and scanning TEM (STEM) images, Fe₂O₃ NPs with the diameter of 3–5 nm are randomly distributed on the sidewall of fCNT, revealing the nanocrystalline structure. The chemical identity and interaction of the fCNT/Fe₂O₃ composite are investigated by FT-IR, Raman and XPS analyses. In particular, the fCNT/Fe₂O₃ composite is solution-processable in a form of binder free and self-standing film. Such a free-standing electrode film based on the fCNT/Fe₂O₃ composite achieve the discharge capacity of 413 mAh g⁻¹ which is much greater than 34 mAh g⁻¹ of the CNT and 191 mAh g⁻¹ of the fCNT due to the redox reaction of Fe₂O₃ NPs. Moreover, the fCNT/Fe₂O₃ composite show the coulombic efficiency of 98% and the capacity fading from 272 mAh g⁻¹ to 182 mAh g⁻¹ after 50 cycles of charge/discharge.     

Facile synthesis of monodisperse ultrasmall Fe3O4 nanoparticles on graphene nanosheets with excellent microwave absorption performance

Journal of Materials Science: Materials in Electronics - The monodispersed ultrasmall Fe3O4 nanoparticles (NPs) have been anchored on reduced graphene oxide (rGO) nanosheets through a one-step...     

Plasma synthesis of carbon powder with embedded Fe3C nanoparticles for magnetic separation of biomolecules

In this article we report the synthesis of a carbon powder with embedded magnetic nanoparticles. Precursors, ferrocene and ethylene glycol, were loaded in a quartz combustion tube and pyrolysed by microwave plasma under vacuum conditions. The synthesized powder was similar to graphite in texture, but strongly attracted by magnetic fields. Several analytical techniques were carried out, including X-ray Photoelectron Spectroscopy, Transmission and Scanning Electron microscopies, X-ray Diffraction and BET isotherm. The resulting material is a ramified framework of carbon, similar to activated carbon, with embedded Fe₃C/C core-shell nanoparticles. BET analysis gives a type IV isotherm, common for mesoporous adsorbents. A protocol was developed for the purification of nucleic acids by magnetic separation. The material gives satisfactory results for DNA extraction. It is concluded that due to the non-toxicity nature of the C shells and the outstanding magnetic property of the Fe₃C nanoparticles this absorptive carbonaceous material can be applied in fields of biomedicine or biotechnology.     

In situ modifying of carbon tube-in-tube nanostructures with highly active Fe(2)O(3) nanoparticles

A novel in situ method based on a liquid membrane templated self-assembly process is employed to modify carbon tube-in-tube nanostructures (TTCNTs) with Fe(2)O(3) nanoparticles. The as-obtained Fe(2)O(3) modified TTCNTs (Fe(2)O(3)/TTCNTs) nanocomposites are well constructed and the Fe(2)O(3) nanoparticles are well dispersed and decorated on the outer, inner and intramolecular surfaces of TTCNTs. In addition, the Fe(2)O(3)/TTCNTs nanocomposites are employed as catalysts for selective catalytic reduction (SCR) of NO with NH(3) and show high SCR catalytic activity, indicating that the novel multiple intramolecular channels and unique surface chemistry of the TTCNTs should play an important role in improving the properties of?TTCNTs.     

Facile synthesis of capped γ-Fe2O3 and Fe3O4 nanoparticles

Facile methods for the selective preparation of capped iron oxide nanoparticles (γ-Fe₂O₃, Fe₃O₄) are described. The magnetic oxides are obtained via oxidative transformation of an iron hydroxide gel using H₂O₂ or (NH₄)₂S₂O₈ solutions as oxidants. Capping with oleic or other aliphatic acids is established simultaneously in one step by adding a toluene solution of the capping agent and refluxing the resulting biphase system. The method is simple, soft and affords nanoparticles of γ-Fe₂O₃ or Fe₃O₄ of controlled size depending on the reaction conditions. The capped nanoparticles are readily soluble in organic or aqueous media according to the nature of the sheath surrounding the surface of the particles, providing stable and high concentration ferrofluids.     

In situ construction of graded porous carbon matrix to strengthen structural stability of NiFe2O4 nanoparticles as high-capacity anodes of Li-ion batteries

Transition metal oxides are considered as promising anode materials of high-performance lithium-ion batteries because of their higher specific capacities than that of commercial graphite. However, they still suffer from huge volume expansion/contraction during cycling, leading to fast decay of the reversible capacity and poor cycle stability. In this work, a graded porous carbon matrix has been in situ constructed successfully to strengthen structural stability of NiFe₂O₄ nanoparticles via a facile and green low-temperature combustion method. The calcination temperature has a significant effect on the purity and electrochemical performances of the final NiFe₂O₄/C composites. NiFe₂O₄/C prepared at 350 °C shows a high first discharge capacity of 1385.8 mAh g^?1 at 200 mA g^?1, excellent cycle stability, and good rate capability. This excellent electrochemical performance may be attributed to its favorable graded porous structure. The carbon matrix can effectively protect the NiFe₂O₄ nanoparticles, buffer the surface stress caused by volume expansion/contraction, and facilitate the transmission of electrons and Li⁺ ions. The symbiotic relationship between NiFe₂O₄ active nanoparticles and graded porous carbon matrix strengthens the structural stability of the electrode, which expands the way of designing high-performance electrode materials for secondary rechargeable batteries.