Anode Electrode For Lithium-ion Batteries Research Articles

SnO2 nanoparticles anchored on vertically aligned graphene with a high rate, high capacity, and long life for lithium storage

As a high-theoretical-capacity (782mA hg-1), low-cost and low-toxicity material, SnO2 has attracted intense interest for use as an anode electrode for lithium-ion batteries (LIBs). Despite intensive study, the practical use of SnO2-based anodes is hindered by their poor capacity retention and low rate capacity resulting from their large specific-volume changes and kinetic limitations in ion/electron transfer during the lithium ion insertion/extraction process. Improving the performance of SnO2-based electrodes has become one of the most popular scientific and industrial efforts. Herein, we present a type of SnO2-graphene composite anode in which SnO2 nanoparticles are uniformly anchored on both sides of vertically aligned graphene nanosheets (SnO2-VAGN-SnO2). The VAGNs sandwiched by the nanoparticles can supply rapid ion and electron transport pathways for Li+ and e-. Such integrated electrodes exhibit high specific capacity and excellent cycling stability, even at high current densities. The cells can cycle more than 5,000 times and retain a reversible capacity of 210mA h g-1 at 9 A g-1. A high current density of up to 20 A g-1 is achieved, and the power and energy density can reach 1576.75W kg-1 and 110.14 Wh kg-1, respectively. These performances indicate that the composite could offer the advantages of both LIBs (high energy density) and supercapacitors (high power density).

Highly porous structure strategy to improve the SnO2 electrode performance for lithium-ion batteries

SnO2 is a promising high-capacity anode material for lithium-ion batteries (LIBs), but it usually exhibits poor cycling stability due to its huge volume variation during the lithium uptake and release process. In this work, SnO2 nanofibers and nanotubes with highly porous (HPNFs, HPNTs) structure have been synthesized by a facile emulsion electrospinning and subsequent calcination process in air at 500 °C. Pores with a diameter range of 2-30 nm were distributed evenly on the surface of the nanofibers and nanotubes. The HPNFs and HPNTs manifested high capacities and excellent cycle performance as the anode electrode for LIBs, and they can deliver reversible capacities of 583 and 645 mA h g(-1) at a current density of 100 mA g(-1) after 50 cycles, respectively. When the current density is up to 5 A g(-1), the electrodes still exhibit a good retention, and the reversible capacities were about 370 and 432 mA h g(-1), which performs much better than the nanofibers and nanotubes without a porous structure. Our results demonstrated that this simple method could be extended for the synthesis of porous metal oxide nanotubes with high performances in the applications of lithium ion batteries and other fields.

Graphene Based Electrode Using in Rechargeable Lithium Ion Batteries

Graphene as high capacity anode materials for rechargeable lithium ion batteries (LIBs) have been studied extensively with the aim of enhancing lithium ion and electron transport, lowering the stress caused by their volume changes during the charge/discharge processes of electrodes in LIBs. As we know, graphite is a practical anode material used for LIBs, because of its capability for reversible lithium ion intercalation in the layered crystals, and the structural similarities of graphene to graphite may provide another type of intercalation anode compound. In this work, the anode electrodes of LIBs include graphene nanosheet (GNS) and graphene nanosheet + carbon nanotubes (GNS+CNT). GNS was prepared through the thermal exfoliation of oxided graphite (OGS), which was synthesized by a modified Hummers method. The specific capacity of GNS was found to be 280 mAh/g after 200 cycles at 1C, and this was increased up to 320 mAh/g by the incorporation of macromolecules of CNT to the GNS.

Facile scalable synthesis of Co3O4/carbon nanotube hybrids as superior anode materials for lithium-ion batteries

In this report, Co3O4/multiple-wall carbon nanotube (MWCNT) hybrid materials were synthesized via strong ultrasonication-assisted shaking and magnetic stirring processes. The prepared samples were well characterized by utilizing powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy techniques. Results indicated that the resulting Co3O4 nanoparticles were highly dispersed in the MWCNT network backbone and further form Co3O4/MWCNT hybrid materials. The obtained Co3O4/MWCNT hybrids can be employed as anode electrode in Lithium-ion batteries and deliver as high as discharge capacity of 1250mAhg−1 at a current density of 0.2C, additionally, 81% of the discharge capacity for sample 2 with 20wt.% MWCNT loading could be retained after 70 cycles, which could be associated with the specific hybrid structure of the electrode as well as the addition of MWCNT. Most importantly, the present synthetic approach is facile, controllable, and scalable, which allowing it more easily adapted to prepare other hybrid materials with specific architectures.

Failure mechanism of bulk silicon anode electrodes for lithium-ion batteries

Silicon has been investigated extensively as a promising anode material for rechargeable lithium-ion batteries. Understanding the failure mechanism of silicon-based anode electrodes for lithium-ion batteries is essential to solve the problem of low coulombic efficiency and capacity fading on cycling and also to further commercialize this very new energetic material in cells. To reach this goal, the structure changes of bulk silicon particles and electrode after cycling were studied using ex-situ scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The SEM images indicated that the microstructural changes of the bulk silicon particles during cycling led to a layer rupture of the electrode and then the breakdown of the conductive network and the failure of the electrode. The result contributes to the basic understanding of the failure mechanism of a bulk silicon anode electrode for lithium-ion batteries.

Electric Papers of Graphene-Coated Co3O4 Fibers for High-Performance Lithium-Ion Batteries

A facile strategy to synthesize the novel composite paper of graphene nanosheets (GNS) coated Co(3)O(4) fibers is reported as an advanced anode material for high-performance lithium-ion batteries (LIBs). The GNS were able to deposit onto Co(3)O(4) fibers and form the coating via electrostatic interactions. The unique hybrid paper is evaluated as an anode electrode for LIBs, and it exhibits a very large reversible capacity (∼840 mA h g(-1) after 40 cycles), excellent cyclic stability and good rate capacity. The substantially excellent electrochemical performance of the graphene/Co(3)O(4) composite paper is the result from its unique features. Notably, the flexible structure of graphenic scaffold and the strong interaction between graphene and Co(3)O(4) fibers are beneficial for providing excellent electronic conductivity, short transportation length for lithium ions, and elastomeric space to accommodate volume varies upon Li(+) insertion/extraction.

A three-dimensional graphene scaffold supported thin film silicon anode for lithium-ion batteries

Three-dimensional (3D) silicon (Si) thin films supported on a graphene scaffold were prepared as an anode electrode for lithium-ion batteries. The as-prepared Si anode exhibited a gravimetric capacity as high as 1560 mA h g−1 at a current density of 797 mA g−1 and a capacity retention of 84% after 500 cycles relative to the capacity value in the 50th cycle. Meanwhile, specific capacities of 1083 and 803 mA h g−1 were demonstrated after 1200 cycles at 2390 mA g−1 and 7170 mA g−1, respectively. The high specific capacity and excellent cyclability and rate performance could be ascribed to the highly porous 3D architecture of the graphene scaffold, which possesses good electrical conductivity and the feature of mechanical flexibility. The results presented here pave a new way for synthesis of Si–graphene hybrid materials using microwave plasma-enhanced chemical vapor deposition as robust and scalable Si-based anodes for lithium ion batteries.

Electron Microscopy Observation of the Chemical Conversion from Cu2O to CuO as Anode Electrodes of Lithium-Ion Batteries

Electron Microscopy Observation of the Chemical Conversion from Cu₂O to CuO as Anode Electrodes of Lithium-Ion Batteries