Linjie Zhi

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.

Graphene-DNA hybrids: self-assembly and electrochemical detection performance

Graphene combines with single-stranded DNA by a self-assembly process under strong ultrasonication and in the resulting water-dispersible graphene-DNA hybrids, monolayers of globular ss-DNA molecules are adsorbed on both sides of the graphene sheets by a non-covalent π–π stacking. The cyclic voltammetry results of the graphene-DNA hybrids coated electrodes demonstrate a well-defined and nearly symmetrical redox characteristic which means an enhanced electron transfer on the electrode surface as compared to the uncoated glassy carbon electrodes. Accordingly, the coated ones show apparently better sensing performance towards hydrogen peroxide which is characterized by large detection range, rapid response and high sensitivity.

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.

Catalytic Effects in Lithium–Sulfur Batteries: Promoted Sulfur Transformation and Reduced Shuttle Effect

Abstract Lithium–sulfur (Li–S) battery has emerged as one of the most promising next‐generation energy‐storage systems. However, the shuttle effect greatly reduces the battery cycle life and sulfur utilization, which is great deterrent to its practical use. This paper reviews the tremendous efforts that are made to find a remedy for this problem, mostly through physical or chemical confinement of the lithium polysulfides (LiPSs). Intrinsically, this “confinement” has a relatively limited effect on improving the battery performance because in most cases, the LiPSs are “passively” blocked and cannot be reused. Thus, this strategy becomes less effective with a high sulfur loading and ultralong cycling. A more “positive” method that not only traps but also increases the subsequent conversion of LiPSs back to lithium sulfides is urgently needed to fundamentally solve the shuttle effect. Here, recent advances on catalytic effects in increasing the rate of conversion of soluble long‐chain LiPSs to insoluble short‐chain Li2S2/Li2S, and vice versa, are reviewed, and the roles of noble metals, metal oxides, metal sulfides, metal nitrides, and some metal‐free materials in this process are highlighted. Challenges and potential solutions for the design of catalytic cathodes and interlayers in Li–S battery are discussed in detail.

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

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.

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.

Rational Design of Carbon‐Rich Materials for Energy Storage and Conversion

Carbon-rich materials have drawn tremendous attention toward a wide spectrum of energy applications due to their superior electronic mobility, good mechanical strength, ultrahigh surface area, and more importantly, abundant diversity in structure and components. Herein, rationally designed and bottom-up constructed carbon-rich materials for energy storage and conversion are discussed. The fundamental design principles are itemized for the targeted preparation of carbon-rich materials and the latest remarkable advances are summarized in terms of emerging dimensions including sp2 carbon fragment manipulation, pore structure modulation, topological defect engineering, heteroatom incorporation, and edge chemical regulation. In this respect, the corresponding structure-property relationships of the resultant carbon-rich materials are comprehensively discussed. Finally, critical perspectives on future challenges of carbon-rich materials are presented. The progress highlighted here will provide meaningful guidance on the precise design and targeted synthesis of carbon-rich materials, which are of critical importance for the achievement of performance characteristics highly desirable for urgent energy deployment.