Guan-Hua Yang

Synthesis of Sn/MoS2/C composites as high-performance anodes for lithium-ion batteries

Tin (Sn) has been considered as one of the most promising anode materials for high-performance lithium ion batteries (LIBs) due to its high theoretical capacity, abundance and low toxicity. However, fast capacity fading and poor rate capability hinder its application in LIBs. Herein, we report a novel composite consisting of few-layer MoS2 and Sn nanoparticles synthesized as an anode for LIBs. In such a composite anode, MoS2 nanosheets provide flexible substrates for the nanoparticle decoration, accommodating the volume changes of Sn during the cycling process, while Sn nanoparticles also can act as spacers to stabilize the composite structure and make the active surfaces of MoS2 nanosheets accessible for electrolyte penetration during the charge/discharge process. Electrochemical measurements demonstrated that the Sn/MoS2/C composite exhibits extremely long cycling stability even at high rate (a reversible capacity of 624.5 mA h g−1 at a current density of 1 A g−1 after 500 cycles) and superior rate capability (1050 mA h g−1 at 100 mA g−1, 895 mA h g−1 at 200 mA g−1, 800 mA h g−1 at 500 mA g−1, 732 mA h g−1 at 1 A g−1 and 630 mA h g−1 at 2 A g−1).

Controlled synthesis of three-dimensional interconnected graphene-like nanosheets from graphite microspheres as high-performance anodes for lithium-ion batteries

Three-dimensional (3D) graphene-based materials have received increasing attention due to their application potential in electrochemical energy storage and conversion. Herein, we demonstrate a facile and efficient strategy to synthesize 3D interconnected graphene-like nanosheets (3DGNs) directly developed from graphite microspheres. The graphene-like nanosheets are interwoven into a unique 3D macroporous network architecture, which can prevent the graphene nanosheets from aggregating effectively. When used as an anode in lithium ion batteries, the 3DGN architecture is capable of reaching an extremely high reversible discharge capacity of 2795.6 mA h g−1, while maintaining a good electrochemical stability with a very high capacity of 1708.5 mA h g−1 after 120 cycles. The superior electrochemical performances of the 3DGN architecture may be attributed to its unique structural features, such as efficient ion/electron conductive channels of 3D interconnected nanosheets, enhanced specific surface area as well as its favorable surface structural features.

Facile synthesis of Sn/MoS2/C composite as an anode material for lithium-ion batteries with outstanding performance

A facile strategy for preparing a novel Sn/MoS2/C composite has been developed via a simple hydrothermal route and then annealing in an Ar atmosphere. The synthesis of layer-structured MoS2 and amorphous carbon can effectively restrict the volume change of Sn during the charge and discharge process. The Sn/MoS2/C composite was evaluated as an anode material for lithium-ion batteries, and exhibits a stable and high reversible capacity of 707 mA h g−1 at 500 mA g−1 after 100 cycles. The significantly improved Li ion storage and stable capability are attributed to the layer-structured MoS2 nanosheets and the amorphous carbon coated layer, which alleviate the large volume changes of Sn and enhance the electron and Li ion diffusion transport in the composite.

Facile synthesis of a novel Al-based composite as an anode for lithium-ion batteries

A facile ball-milling method is developed to synthesize an Al/MoS2/C composite, which can be used for scalable industrial mass production. The composite is characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), galvanostatic cycling and cyclic voltammetry. The electrochemical measurements demonstrate that the Al/MoS2/C composite has a greatly improved electrochemical performance in comparison with pure Al. After 40 cycles, the capacity retentions of Al-40 wt%, Al-50 wt% and Al-60 wt% are 451.3 mA h g−1, 419.6 mA h g−1 and 378.2 mA h g−1, respectively. This improved electrochemical performance may be attributed to the layer-structure MoS2/C composite which can not only buffer the volume change but also provide capacity stability for the composite during the charge and discharge process. This suggests that the Al/MoS2/C composite has a potential possibility to be developed as an anode material for LIBs.

Electroless plating of a Sn–Ni/graphite sheet composite with improved cyclability as an anode material for lithium ion batteries

A Sn–Ni/graphite sheet composite is synthesized by a simple electroless plating method as an anode material for lithium ion batteries (LIBs). The microstructure and electrochemical properties of the composite are characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), cyclic voltammetry (CV), and AC impedance spectroscopy. The results show that the as-prepared composite has Sn–Ni nanoparticles around 100 nm in size, where metallic Ni acts as an “anchor” to fix metallic Sn. The reunion phenomenon of Sn is alleviated by adding metallic Ni between the metallic Sn and graphite sheets. The Sn–Ni/graphite sheet electrode exhibits a good rate performance with a capability of 637.4, 586.3, 466.7, 371.5, 273.6, 165.3 and 97.3 mA h g−1 at a current density of 0.1, 0.2, 0.5, 1.0, 2.0, 5.0 and 10 A g−1, respectively. The good electrical conductivity of Ni, high specific capacity of Sn and excellent cycling capability of the graphite sheets have a synergistic effect and are the main reasons behind the superior electrochemical performance. Furthermore, the as-prepared composite exhibits excellent lithium storage capacity and the reversible capacity increased as the cycle number increased.