MnO-carbon hybrid nanofiber composites as superior anode materials for lithium-ion batteries

A Novel Triple Crosslinking Strategy on Carbon Nanofiber Membranes as Flexible Electrodes for Lithium-Ion Batteries

In order to solve the problem of low electrical conductivity of carbon nanofiber membranes, a novel triple crosslinking strategy, including pre-rolling, solvent and chemical imidization crosslinking, was proposed to prepare carbon nanofiber membranes with a chemical crosslinking structure (CNMs-CC) derived from electrospinning polyimide nanofiber membranes. The physical-chemical characteristics of CNMs-CC as freestanding anodes for lithium-ion batteries were investigated in detail, along with carbon nanofiber membranes without a crosslinking structure (CNMs) and carbon nanofiber membranes with a physical crosslinking structure (CNMs-PC) as references. Further investigation demonstrates that CNMs-CC exhibits excellent rate performance and long cycle stability, compared with CNMs and CNMs-PC. At 50 mA g⁻¹, CNMs-CC delivers a reversible specific capacity of 495 mAh g⁻¹. In particular, the specific capacity of CNMs-CC is still as high as 290.87 mAh g⁻¹ and maintains 201.38 mAh g⁻¹ after 1000 cycles at a high current density of 1 A g⁻¹. The excellent electrochemical performance of the CNMs-CC is attributed to the unique crosslinking structure derived from the novel triple crosslinking strategy, which imparts fast electron transfer and ion diffusion kinetics, as well as a stable structure that withstands repeated impacts of ions during charging and discharging process. Therefore, CNMs-CC shows great potential to be the freestanding electrodes applied in the field of flexible lithium-ion batteries and supercapacitors owing to the optimized structure strategy and improved properties.

Anchoring ZnO Nanoparticles in Nitrogen-Doped Graphene Sheets as a High-Performance Anode Material for Lithium-Ion Batteries

A novel binary nanocomposite, ZnO/nitrogen-doped graphene (ZnO/NG), is synthesized via a facile solution method. In this prepared ZnO/NG composite, highly-crystalline ZnO nanoparticles with a size of about 10 nm are anchored uniformly on the N-doped graphene nanosheets. Electrochemical properties of the ZnO/NG composite as anode materials are systematically investigated in lithium-ion batteries. Specifically, the ZnO/NG composite can maintain the reversible specific discharge capacity at 870 mAh g⁻¹ after 200 cycles at 100 mA g⁻¹. Besides the enhanced electronic conductivity provided by interlaced N-doped graphene nanosheets, the excellent lithium storage properties of the ZnO/NG composite can be due to nanosized structure of ZnO particles, shortening the Li⁺ diffusion distance, increasing reaction sites, and buffering the ZnO volume change during the charge/discharge process.

Preparation of novel two-stage structure MnO micrometer particles as lithium-ion battery anode materials

MnO micrometer particles with a two-stage structure (composed of mass nanoparticles) were produced via a one-step hydrothermal method using histidine and potassium permanganate (KMnO₄) as reagents, with subsequent calcination in a nitrogen (N₂) atmosphere.

Fast Preparation of Porous MnO/C Microspheres as Anode Materials for Lithium-Ion Batteries

Porous MnO/C microspheres have been successfully fabricated by a fast co-precipitation method in a T-shaped microchannel reactor. The structures, compositions, and electrochemical performances of the obtained MnO/C microspheres are characterized by X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller analysis, charge-discharge testing, cyclic voltammograms, and electrochemical impedance spectra. Experimental results reveal that the as-prepared MnO/C, with a specific surface area of 96.66 m²·g^-1 and average pore size of 24.37 nm, exhibits excellent electrochemical performance, with a discharge capacity of 655.4 mAh·g^-1 after cycling 50 times at 1 C and capacities of 808.3, 743.7, 642.6, 450.1, and 803.1 mAh·g^-1 at 0.2, 0.5, 1, 2, and 0.2 C, respectively. Moreover, the controlled method of using a microchannel reactor, which can produce larger specific surface area porous MnO/C with improved cycling performance by shortening lithium-ion diffusion distances, can be easily applied in real production on a large scale.

2D Film of Carbon Nanofibers Elastically Astricted MnO Microparticles: A Flexible Binder-Free Anode for Highly Reversible Lithium Ion Storage

MnO as anode materials has received particular interest owing to its high specific capacity, abundant resources, and low cost. However, serious problems related to the large volume change (>170%) during the lithiation/delithiation processes still results in poor rate capability and fast capacity decay. With homogenous crystals of MnO grown in the network of carbon nanofibers (CNF), binding effect of CNF can effectively weaken the volume change of MnO during cycles. In this work, a CNF/MnO flexible electrode for lithium-ion batteries is designed and synthesized. The CNF play the roles of conductive channel and elastically astricting MnO particles during lithiation/delithiation. CNF/MnO as binder-free anode delivers specific capacity of 983.8 mAh g^-1 after 100th cycle at a current density of 0.2 A g^-1 , and 600 mAh g^-1 at 1 A g^-1 which are much better than those of pure MnO and pure CNF. The ex-situ morphologies clearly show the relative volume change of MnO/CNF as anode under various discharging and charging times. CNF can elastically buffer the volume change of MnO during charging/discharging cycles. A facile and scalable approach for synthesizing a novel flexible binder-free anode of CNF/MnO for potential application in highly reversible lithium storage devices is presented.

Chemical vapor deposition-assisted fabrication of a graphene-wrapped MnO/carbon nanofibers membrane as a high-rate and long-life anode for lithium ion batteries

Novel MnO/CNFs@G membrane by electrospinning and APCVD; this anode with high specific capacity and longest cycling life is of great interest to high energy thin film or flexible Li-ion battery.

A facile electrospinning and electrospraying synchronization technique for preparation of high performance MnO/C@rGO composite anodes for lithium storage

A facile electrospinning and electrospraying synchronization technique is used to assemble 1D nanowires with 2D graphene sheets to build as 3D MnO/C@rGO composite thin film. The raw material MnO₂powder was recovered from spent Zn/MnO₂batteries.

Improved lithium-ion battery anode capacity with a network of easily fabricated spindle-like carbon nanofibers

A novel network of spindle-like carbon nanofibers was fabricated via a simplified synthesis involving electrospinning followed by preoxidation in air and postcarbonization in Ar. Not only was the as-obtained carbon network comprised of beads of spindle-like nanofibers but the cubic MnO phase and N elements were successfully anchored into the amorphous carbon matrix. When directly used as a binder-free anode for lithium-ion batteries, the network showed excellent electrochemical performance with high capacity, good rate capacity and reliable cycling stability. Under a current density of 0.2 A g^-1, it delivered a high reversible capacity of 875.5 mAh g^-1 after 200 cycles and 1005.5 mAh g^-1 after 250 cycles with a significant coulombic efficiency of 99.5%.

K2 Mn4 O8 /Reduced Graphene Oxide Nanocomposites for Excellent Lithium Storage and Adsorption of Lead Ions

Ion diffusion efficiency at the solid-liquid interface is an important factor for energy storage and adsorption from aqueous solution. Although K₂ Mn₄ O₈ (KMO) exhibits efficient ion diffusion and ion-exchange capacities, due to its high interlayer space of 0.70 nm, how to enhance its mass transfer performance is still an issue. Herein, novel layered KMO/reduced graphene oxide (RGO) nanocomposites are fabricated through the anchoring of KMO nanoplates on RGO with a mild solution process. The face-to-face structure facilitates fast transfer of lithium and lead ions; thus leading to excellent lithium storage and lead ion adsorption. The anchoring of KMO on RGO not only increases electrical conductivity of the layered nanocomposites, but also effectively prevents aggregation of KMO nanoplates. The KMO/RGO nanocomposite with an optimal RGO content exhibits a first cycle charge capacity of 739 mA h g^-1 , which is much higher than that of KMO (326 mA h g^-1 ). After 100 charge-discharge cycles, it still retains a charge capacity of 664 mA h g^-1 . For the adsorption of lead ions, the KMO/RGO nanocomposite exhibits a capacity of 341 mg g^-1 , which is higher than those of KMO (305 mg g^-1 ) and RGO (63 mg g^-1 ) alone.

Three-dimensional nanoarchitecture SnSbZn–C composite nanofibers as anode materials for lithium-ion batteries

Electrospun SnSbZn–C composite nanofibers as anode materials showed increased performance for lithium ion batteries.