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Multicomponent metal selenides with heterostructures are believed to effectively activate the surface pseudocapacitive contribution and improve the electrochemical dynamics, thus achieving high-performance anodes for sodium ion batteries (SIBs). Herein, a carbon coated CoSe2/Sb2Se3 heterojunction (CoSe2/Sb2Se3@C) is designed and constructed via an ion-exchange reaction between Co and Sb, and the subsequent selenization step. It is found that the hetero-structure and carbon shell effectively boost the charge transfer in the CoSe2/Sb2Se3@C composite electrode. The highly pseudocapacitive Na+ storage contribution is acquired due to the structural benefits of the heterojunction. Therefore, the CoSe2/Sb2Se3@C anode affords good cycling stability (264.5 mA h g−1 after 1000 cycles at 2 A g−1) and excellent rate capability (266.0 mA h g−1 at 5 A g−1). This study supplies a reference for developing an advanced anode with multicomponent and heterojunction structures for energy storage. [ABSTRACT FROM AUTHOR]

Abstract MoS 2 shows promising potential in the application of lithium ion batteries (LIBs) or sodium ion batteries (SIBs), however, suffering from the sluggish kinetics and terrible volume expansion. Here we fabricate interlayer-expanded VMo 2 S 4 nanosheets onto RGO and exhibit excellent electrochemical properties for lithium and sodium storage. The 2D nature and interlayer-expanded feature assure the shortened ion transfer path and improved diffusion kinetics. RGO substrates enhance the electric conductivity and preserve the material integrity. Based on such benefits, the present sample serves as advanced anode for both LIBs and SIBs, delivering reversible capacities of 1081 mAh g−1 for LIBs and 254 mAh g−1 for SIBs after 200 cycles at 1 A g−1. Graphical abstract Image 1 Highlights • Interlayer-expanded VMo 2 S 4 nanosheets on RGO are developed. • V dopants induce enlarged interlayer and synergism between V and Mo. • RGO improves conductivity and buffers the volume variation. • 2D feature shortens ion diffusion path. • High and fast lithium/sodium storage are obtained. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) nanostructures and their hybrids have triggered intensive attention in energy storage and conversion field owing to their structural benefits. This work firstly prepares 2D hybrids of MoS 2 nanosheets with B, N co-doped graphene nanosheets as advanced anode material for lithium-ion batteries. The rational use of 2D nanomaterials can supply large surface area for lithium storage and shorten Li + diffusion length. The smart structure design can not only effectively enhance electrical conductivity of composite electrode, but also relax the volume change of MoS 2 upon electrochemical cycling. Due to the structural and compositional advantages, the present sample exhibits excellent anode performance with large and stable lithium storage, as well as high rate capability. [ABSTRACT FROM AUTHOR]

Abstract The advancements of sustainable energy storage and conversion systems will benefit from the exploring of cost-effective and high-performance electrode materials with multifunctions. In this study, a novel three-dimensional (3D) electrode, consisting of hybridized Ni(PO 3) 2 -MnPO 4 nanosheet array on self-supported conductive nickel foam (Ni(PO 3) 2 -MnPO 4 /NF), is established to demonstrate the promising applications of an class of transition metal phosphates (TMPOs) for electrochemical water splitting and supercapacitors. By means of the Ni(PO 3) 2 -MnPO 4 /NF electrode with rationally designed nanosheet array structure and abundant defects, we demonstrate the good catalytic activity of TMPOs for hydrogen evolution reaction (125 mV at 10 mA cm−2). It is also revealed as a robust oxygen-evolving catalyst, yielding a current density of 10 mA cm−2 at ultralow overpotential of 116 mV (corresponding to the electrode potential of 1.346 V). When tested as bifunctional electrocatalysts to drive overall water splitting, the applied potential difference is as low as 1.41 V for the whole cell to achieve the current density of 10 mA cm−2. Moreover, Ni(PO 3) 2 -MnPO 4 /NF could serve as excellent supercapacitor electrode with superior capacitance behavior (areal specific capacitance of 14.48 F cm−2 at 5 mA cm−2) and good stability. In an aqueous asymmetric supercapacitor, a high energy density of 45.6 Wh kg−1 is obtained at a power density of 1.1 kW kg−1. Highlights • Ni(PO 3) 2 -MnPO 4 nanosheet array on conductive nickel foam is prepared. • Good HER activity is firstly demonstrated for transition metal phosphates. • Acting as robust bifunctional catalyst for overall water splitting. • Exhibiting high capacitance and stability as supercapacitor electrode. • Assembling a high-performance asymmetric capacitor with activated carbon. [ABSTRACT FROM AUTHOR]

Improving the electrochemical hydrogen evolution reaction (HER) activity of inexpensive catalysts is central in the area of sustainable energy conversion, yet remains an extraordinary challenge. Here, we firstly construct MoS 2 nanosheets vertically anchored on C 3 N 4 for high-efficiency electrochemical HER. The rational structure design endows MoS 2 nanosheets with combined advantages of maximally exposed edges and defect-rich structure. Moreover, the hybrid MoS 2 -C 3 N 4 possesses remarkably improved electrochemically active surface area and enhanced electrical conductivity than MoS 2 . Therefore, MoS 2 -C 3 N 4 exhibits robust electrocatalytic HER activity, including low overpotential (158 mV) required to generate the current density of 10 mA cm −2 , low Tafel slope (52 mV decade −1 ), and high current density (92 mA cm −2 at overpotential of 300 mV). [ABSTRACT FROM AUTHOR]

Exploration of novel advanced materials for energy conversion and storage is on the research focus. Herein, we firstly develop FeMo 4 S 6 nanosheets via a hydrothermal process as advanced energy materials. TEM and XRD characterizations reveal that FeMo 4 S 6 nanosheets possess distinctive layered structure with an interlayer distance of 0.64 nm and 10–14 layers in thickness. Rooted in the intriguing layered 2D structural advantages and multicomponent effect, the sample exhibits large and stable lithium storage properties when it is used as anode material for lithium-ion batteries. It is also evaluated as electrocatalyst for water splitting and shows promising catalytic activity for hydrogen evolution, including low onset overpotential and stable cycling durability. [ABSTRACT FROM AUTHOR]

Development of noble-metal-free catalysts towards highly efficient electrochemical oxygen evolution reaction (OER) is critical but challenging in the renewable energy area. Herein, we firstly embed NiFe LDHs quantum dots (QDs) into expanded graphite (NiFe LDHs/EG) via in-situ confined formation process. The interlayer spacing of EG layers acts as nanoreactors for spatially confined formation of NiFe LDHs QDs. The QDs supply huge catalytic sites for OER. The in-situ decoration endows the strong affinity between QDs with EG, thus inducing fast charge transfer. Based on the aforementioned benefits, the designed catalyst exhibits outstanding OER properties, in terms of small overpotential (220 mV required to generate 10 mA cm −2 ), low Tafel slope, and good durable stability, making it a promising candidate for inexpensive OER catalyst. [ABSTRACT FROM AUTHOR]