Debin Kong

Rational design of MoS2@graphene nanocables: towards high performance electrode materials for lithium ion batteries

Here, we have successfully developed a novel contact mode between MoS2 and graphene, where graphene rolls up into a hollow nanotube and thin MoS2 nanosheets are uniformly standing on the inner surface of graphitic nanotubes, thus forming mechanically robust, free-standing, interwoven MoS2@graphene nanocable webs (MoS2@G). Such a hybrid structure can maximize the MoS2 loading in the electrode in which over 90% of MoS2 nanosheets with stacked layer number of less than 5 can be installed. Remarkably, when calculated on the basis of the whole electrode, this binder free electrode not only shows high specific capacity (ca. 1150 mA h g−1) and excellent cycling performance (almost 100% capacity retention even after 160 cycles at a current density of 0.5 A g−1) but exhibits a surprisingly high-rate capability of 700 mA h g−1 at the rate of 10 A g−1 despite such a high MoS2 loading content, which is one of the best results of MoS2-based electrode materials ever reported thus far.

Encapsulating V2O5 into carbon nanotubes enables the synthesis of flexible high-performance lithium ion batteries

Correction for ‘Encapsulating V2O5 into carbon nanotubes enables the synthesis of flexible high-performance lithium ion batteries’ by Debin Kong et al., Energy Environ. Sci., 2016, 9, 906–911.

A novel SnS2@graphene nanocable network for high-performance lithium storage

A unique SnS2@graphene nanocable structure with a novel contact model between SnS2 nanosheets and graphene has been successfully fabricated, in which the graphene layers are rolled up to encapsulate the SnS2 nanosheets, forming a mechanically robust, free-standing SnS2@graphene nanocable network. This distinctive structure provides an effective architecture as an electrode in lithium ion batteries to effectively accommodate the volume change of SnS2 during the charge–discharge cycling, facilitates the easy access of electrolyte to the active electrode materials, and also offers a continuous conductive network for the whole electrode. Interestingly, this binder-free electrode not only shows high specific capacity and excellent cycling performance with a specific capacity of 720 mA h g−1 even after 350 cycles at a current density of 0.2 A g−1 and over 93.5% capacity retention, but exhibits a high-rate capability of 580 mA h g−1 at a current rate of 1 A g−1

Disassembly–Reassembly Approach to RuO2/Graphene Composites for Ultrahigh Volumetric Capacitance Supercapacitor

A porous, yet compact, RuO2 /graphene hybrid is successfully prepared by using a disassembly-reassembly strategy, achieving effective and uniform loading of RuO2 nanoparticles inside compact graphene monolith. The disassembly process ensures the uniform loading of RuO2 nanoparticles into graphene monolith, while the reassembly process guarantees a high density yet simultaneously unimpeded ion transport channel in the composite. The resulting RuO2 /graphene hybrid possesses a density of 2.63 g cm-3 , leading to a record high volumetric capacitance of 1485 F cm-3 at the current density of 0.1 A g-1 . When the current density is increased to 20 A g-1 , it remains a high volumetric capacitance of 1188 F cm-3 . More importantly, when the single electrode mass loading is increased to 12 mg cm-2 , it still delivers a high volumetric capacitance of 1415 F cm-3 at the current density of 0.1 A g-1 , demonstrating the promise of this disassembly-reassembly approach to create high volumetric performance materials for energy storage applications.

Silicene Flowers: A Dual Stabilized Silicon Building Block for High-Performance Lithium Battery Anodes

Nanostructuring is a transformative way to improve the structure stability of high capacity silicon for lithium batteries. Yet, the interface instability issue remains and even propagates in the existing nanostructured silicon building blocks. Here we demonstrate an intrinsically dual stabilized silicon building block, namely silicene flowers, to simultaneously address the structure and interface stability issues. These original Si building blocks as lithium battery anodes exhibit extraordinary combined performance including high gravimetric capacity (2000 mAh g-1 at 800 mA g-1), high volumetric capacity (1799 mAh cm-3), remarkable rate capability (950 mAh g-1 at 8 A g-1), and excellent cycling stability (1100 mA h g-1 at 2000 mA g-1 over 600 cycles). Paired with a conventional cathode, the fabricated full cells deliver extraordinarily high specific energy and energy density (543 Wh kgca-1 and 1257 Wh Lca-1, respectively) based on the cathode and anode, which are 152% and 239% of their commercial counterparts using graphite anodes. Coupled with a simple, cost-effective, scalable synthesis approach, this silicon building block offers a horizon for the development of high-performance batteries.

Nitrogen‐Enriched Carbon/CNT Composites Based on Schiff‐Base Networks: Ultrahigh N Content and Enhanced Lithium Storage Properties

To improve the electrochemical performance of carbonaceous anodes for lithium ion batteries (LIBs), the incorporation of both well-defined heteroatom species and the controllable 3D porous networks are urgently required. In this work, a novel N-enriched carbon/carbon nanotube composite (NEC/CNT) through a chemically induced precursor-controlled pyrolysis approach is developed. Instead of conventional N-containing sources or precursors, Schiff-base network (SNW-1) enables the desirable combination of a 3D polymer with intrinsic microporosity and ultrahigh N-content, which can significantly promote the fast transport of both Li+ and electron. Significantly, the strong interaction between carbon skeleton and nitrogen atoms enables the retention of ultrahigh N-content up to 21 wt% in the resultant NEC/CNT, which exhibits a super-high capacity (1050 mAh g-1 ) for 1000 cycles and excellent rate performance (500 mAh g-1 at a current density of 5 A g-1 ) as the anode material for LIBs. The NEC/CNT composite affords a new model system as well as a totally different insight for deeply understanding the relationship between chemical structures and lithium ion storage properties, in which chemistry may play a more important role than previously expected.

Pyrolyzed bacterial cellulose/graphene oxide sandwich interlayer for lithium–sulfur batteries

Herein, a facile strategy for the synthesis of sandwich pyrolyzed bacterial cellulose (PBC)/graphene oxide (GO) composite was reported simply by utilizing the large-scale regenerated biomass bacterial cellulose as precursor. The unique and delicate structure where three-dimensional interconnected bacterial cellulose (BC) network embedded in two-dimensional GO skeleton could not only work as an effective barrier to retard polysulfide diffusion during the charge/discharge process to enhance the cyclic stability of the Li–S battery, but also offer a continuous electron transport pathway for the improved rate capability. As a result, by utilizing pure sulfur as cathodes, the Li–S batteries assembled with PBC/GO interlayer can still exhibit a capacity of nearly 600xa0mAh·g−1 at 3C and only 0.055% capacity decay per cycle can be observed over 200 cycles. Additionally, the cost-efficient and environment-friendly raw materials may enable the PBC/GO sandwich interlayer to be an advanced configuration for Li–S batteries.

Fabrication of the reduced preoxidized graphene-based nanofiltration membranes with tunable porosity and good performance

A series of reduced preoxidized graphene membranes (rPGMs) were prepared by reducing the preoxidized graphene membranes (PGMs) at different reduction times. The pore morphology of the membranes and the changes in the specific porosity values along with the water flux parameters were investigated. In addition, the membranes were able to maintain a high dye rejection (>97.5% for methyl orange (MO)) and a good rejection ratio for salt ions (71.2% for MgSO4). The preoxidized graphene-based nanofiltration membranes with tunable porosity exhibit great potential as high-precision molecular sieves for water purification and other applications.

Porous graphene oxide-based carbon artefact with high capacity for methylene blue adsorption

A three-dimensional porous graphene oxide (PGO) material prepared by hydrothermal method was selected to adsorb methylene blue (MB), which demonstrates a high MB adsorption capacity, up to 1100xa0mgxa0g−1 in alkaline solution at room temperature. The influences of different pore structures and different contents of oxygen-containing functional groups on MB adsorption behaviors were studied in detail, which indicated that the high MB adsorption capacity is mainly ascribed to the synergistic effect of the large number of oxygen-containing functional groups and the interconnected 3D porous network. Moreover, based on the investigation on the adsorption kinetics and the effect of pH value on MB adsorption, we propose a two-step adsorption kinetics for PGO, which involved in two interactions between MB molecular and porous graphene oxide-based carbon: electrostatic force and π-π stacking. Besides, the calculation of the activation energies indicates that chemisorption dominates the adsorption for PGO in comparison with physisorption for three-dimensional porous graphene materials which has low adsorption capacity because of the removal of functional groups. The results are of great significance for the design and environmental applications of PGO as a promising adsorbent material for water purification.

WS 2 nanoplates embedded in graphitic carbon nanotubes with excellent electrochemical performance for lithium and sodium storage

WS2 has been considered as a promising anode material due to its high lithium storage capacity as well as fascinating physical properties. However, the insufficient electrical and ionic conductivities deteriorate the rate performance of the batteries. Herein, we report a simple synthetic approach towards graphene-WS2 hybrids by rolling graphene into a hollow nanotube in which WS2 nanoplates are encapsulated. This new electrode design strategy facilitates the fabrication of integrated and binder-free lithium ion battery and sodium ion battery electrodes by combining electrospinning and chemical vapor deposition (CVD) methods. Benefiting from their confined growth and the interconnected in-situ graphitic carbon coating nanocable web, the WS2@G with nano-level WS2 dispersion not only provides an efficiently conductive and electrolyte accessible framework, but effectively alleviates the volume change during the cycling, enabling a mechanically robust binder-free electrode along with the outstanding electrochemical Li+ and Na+ storage properties.摘要本论文通过结构设计及简单方法成功制备一种二维石墨烯-WS2复合结构, 即WS2纳米片嵌入石墨烯化中空纳米碳管中(WS2@G). 这种新的电极结构采用静电纺丝技术和化学气相沉积技术组合的方式, 有利于实现集成化和无粘结剂锂离子或钠离子电池电极材料制备. 采用内部的受限生长以及原位的石墨化碳包覆纳米同轴的互贯网络, 得到纳米尺度WS2片层分散的WS2@G复合结构, 能够提供有效的导电性和电解液浸润性的网络结构, 同时还能够有效地降低电池在充放电循环过程中导致的体积膨胀效应, 最终实现一种高机械性能、 无粘结剂、 优异电化学活性的电极在锂离子或钠离子电池储能领域中的应用.