•Facile solid-state coordination and pyrolysis route for constructing Ni@C network.•Unique structural and compositional superiorities toward lithium storage.•Desirable Li-storage performances in terms of capacity, cycle life, and so forth.Micro/nano-architectured transition-metal@C hybrids possess unique structural and compositional features toward lithium storage, and are thus expected to manifest ideal anodic performances in advanced lithium-ion batteries (LIBs). Herein, we propose a facile and scalable solid-state coordination and subsequent pyrolysis route for the formation of a novel type of micro/nano-architectured transition-metal@C hybrid (i.e., Ni@C nanosheet-assembled hierarchical network, Ni@C network). Moreover, this coordination-pyrolysis route has also been applied for the construction of bare carbon network using zinc salts instead of nickel salts as precursors. When applied as potential anodic materials in LIBs, the Ni@C network exhibits Ni-content-dependent electrochemical performances, and the partially-etched Ni@C network manifests markedly enhanced Li-storage performances in terms of specific capacities, cycle life, and rate capability than the pristine Ni@C network and carbon network. The proposed solid-state coordination and pyrolysis strategy would open up new opportunities for constructing micro/nano-architectured transition-metal@C hybrids as advanced anode materials for LIBs.Download high-res image (342KB)Download full-size image

A novel type of NiO-based anodes, i.e., NiO@polypyrrole hollow spheres (NiO@PPy HSs), has been constructed by using SiO2 spheres as templates. The PPy component serves as an ideal supporting matrix for NiO anodes owing to its high structural stability and electrical conductivity. Thus, the NiO@PPy HSs demonstrate markedly enhanced lithium storage capabilities in terms of cycling stability compared with bare NiO spheres. For example, a high reversible capacity of 520.0 mA h g−1 can be delivered after 200 cycles in NiO@PPy anode at a current density of 100 mA g−1. The superior cycling stability of NiO@PPy HSs makes it an ideal anodic candidate for long-life lithium-ion batteries.

Layer-by-layer (LBL) self-assembled graphene nanosheets, noncovalently functionalized with evenly spread-NH2 groups attached on the linear polyelectrolyte of polyallylamine hydrochloride (PAH), were produced successfully. The fabrication process consisted of two steps. At first, completely exfoliated graphite oxide (GO) species were highly stacked on the surface of a pretreated glassy carbon electrode as a result of the sequential adsorption of the cationic layer of PAH and the anionic layer of oxygen-containing GO through electrostatic and/or hydrophobic interactions. Then, the GO species were chemically reduced by a strong reducing agent, NaBH4. The structural morphology and electrochemical properties of the as-prepared graphene-based multilayer LBL composite electrodes were thoroughly characterized by techniques such as ultraviolet visible (UV-vis) spectroscopy, high-resolution X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and cyclic voltammetry. Combined with differential pulse anodic stripping voltammetry (DPASV), the obtained –NH2 functional group modified nanocomposite electrodes with highly ordered multilayer superconductive graphene showed improved performance for trace detection of heavy metal ions such as Cu(II), resulting in sensitive electrochemical sensors. A linear dynamic range from 0.5 to 50 μM for Cu(II) was obtained under optimized conditions with a relatively low detection limit (S/N = 3) of around 0.35 μM. Our results provide valuable insight for the facile design of highly ordered graphene nanostructures with specific functionality of interest in a vast range, leading to a versatile nanoplatform for environmental or biomedical applications.

A novel type of 3D porous Si–G micro/nanostructure (i.e., 3D interconnected network of graphene-wrapped porous silicon spheres, Si@G network) was constructed through layer-by-layer assembly and subsequent in situ magnesiothermic-reduction methodology. Compared with bare Si spheres, the as-synthesized Si@G network exhibits markedly enhanced anodic performance in terms of specific capacity, cycling stability, and rate capability, making it an ideal anode candidate for high-energy, long-life, and high-power lithium-ion batteries.Keywords: anodes; graphene; interconnected network; lithium-ion batteries; magnesiothermic reduction; silicon;

•Self-made mesoporous carbon (MC) as a novel supporting matrix for SnO2 anode.•High and uniform loading of SnO2 on MC matrix via a facile chemical solution route.•Markedly improved lithium storage capability by virtue of its structure superiority.This paper reports the synthesis of highly loaded SnO2/mesoporous carbon (MC) nanohybrid through a facile chemical solution process and subsequent annealing methodology, by using a novel three-dimensional (3D) MC as a buffering and conducting matrix. Owing to its unique structural characteristics, the MC–SnO2 nanohybrid anode exhibits markedly improved cycling stability and rate capability compared to pure SnO2 nanoparticles, facilitating its application in advanced Li-ion batteries (LIBs) with long cycle life and high power density.

A novel type of graphene supported tin-based alloy, i.e. graphene supported FeSn2 nanocrystals (G–FeSn2 nanohybrid), has been designed and synthesized through a chemical reduction route in a polyol system. When examined as an anode material for lithium-ion batteries (LIBs), the as-synthesized G–FeSn2 nanohybrid displays markedly enhanced Li-storage capabilities in terms of specific capacities and cycling stability compared with bare FeSn2 nanocrystals.

A novel type of graphene-supported Fe3O4 nanohybrid, i.e. graphene wrapped single-crystalline Fe3O4 nanorods (Fe3O4@G nanorods), has been synthesized through a layer-by-layer assembly and a subsequent annealing approach. The as-synthesized Fe3O4@G nanorods have been used as anode materials for lithium-ion batteries, and manifest superior lithium-storage capabilities in terms of high reversible capacities, excellent capacity retention, and high rate capability.

By using large mesoporous carbon (LMC) as a novel host matrix, LMC–FePO4 nanohybrid has been synthesized through a facile homogeneous precipitation process and subsequent annealing approach. When evaluated as a cathode for lithium-ion batteries (LIBs), the LMC–FePO4 nanohybrid exhibits higher specific capacities, improved rate capability, and better cycling performance by virtue of its unique structural characteristics.Graphical abstractHighlights► Self-made nano-CaCO3 templated LMC as a novel supporting matrix for FePO4 cathode. ► The 3D porous structure of LMC is well retained in LMC–FePO4 nanohybrid. ► Its reaction kinetics of lithium insertion/extraction is significantly improved. ► Markedly higher capacities and rate capability by virtue of its structure superiority.

A fast, simple square wave potential method is developed for the fabrication of a three-dimensional (3D) nanoporous gold (NPG) film. The nanostructures are characterized and confirmed by scanning electronic microscopy (SEM) and cyclic voltammetry (CV). The nanostructures modified with self-assembled monolayers (SAMs) are employed as an electrode substrate to immobilize inorganic iron(III) ion. After immobilization, iron(III) ion undergoes an effective direct electron transfer reaction with a pair of well-defined redox peak at −256 ± 10 mV (pH 7.0). The iron(III) ion modified electrode displays the excellent electrocatalytic performance for reduction of hydrogen peroxide, and thus can be used as an electrochemical sensor for detecting hydrogen peroxide with a low detection limit (1.0 × 10−9 M), a wide linear range (9.0 × 10−7∼5.0 × 10−4 M), as well as good stability, selectivity and reproducibility.

Iron phosphate (FePO4) is a promising candidate for the cathode material in lithium-ion cells due to its easy synthesis and low cost. However, the intrinsic drawbacks of FePO4 material (i.e., the low electronic conductivity and the low lithium-ion diffusion coefficient) result in poor capacity. To overcome the shortcomings, multi-wall carbon nanotubes (MWNTs) supported hydrated iron phosphate nanocomposites (FePO4·2H2O/MWNTs) are prepared using a novel homogeneous precipitation method. Meanwhile, the formation mechanism of highly dispersed and ultrafine FePO4·2H2O nanoparticles is discussed in detail. Electrochemical measurements show that FePO4·2H2O/MWNTs nanocomposites have a superior discharge capacity and stability. For example, FePO4·2H2O/MWNTs nanocomposites exhibit a high initial discharge capacity (129.9 mAhg−1) and a stable capacity retention (114.3 mAhg−1 after 20 cycles). The excellent electrochemical performance is attributed to the small particle size of FePO4·2H2O nanoparticles, the good electronic conductivity of MWNTs, and the three-dimensional conductive network structure of FePO4·2H2O/MWNTs nanocomposites.

The surface coverage of 3-mercaptopropylphosphonic acid (HS–CH2CH2CH2–PO3H2, MPPA) self-assembled monolayers (SAMs) on gold surface can be controlled by the dissociation degree of phosphonic acid groups (–PO3H2) in the bulk solution and adsorption time of MPPA molecules under the basic condition. Electrochemical measurements show that the low-density MPPA-SAMs modified gold electrode enhances significantly the kinetics of electron transfer of dopamine (DA), and improves the antifouling capability of modified electrode towards DA oxidation. The present results offer crucial information for design and optimization of the electrochemical sensors for DA determination.

Herein, we have designed and synthesized a novel type of nitrogen-doped carbon-supported CoO nanohybrids, i.e., nitrogen-doped carbon-wrapped porous single-crystalline CoO nanocubes (CoO@N–C nanocubes), by using Co3O4 nanocubes as precursors. Owing to its unique structural features, the as-synthesized CoO@N–C nanocubes demonstrate markedly enhanced anodic performance in terms of reversible capacity, cycling stability, and rate capability, facilitating its application as a high-capacity, long-life, and high-rate anode for advanced lithium-ion batteries.

Layer-by-layer (LBL) self-assembled graphene nanosheets, noncovalently functionalized with evenly spread-NH2 groups attached on the linear polyelectrolyte of polyallylamine hydrochloride (PAH), were produced successfully. The fabrication process consisted of two steps. At first, completely exfoliated graphite oxide (GO) species were highly stacked on the surface of a pretreated glassy carbon electrode as a result of the sequential adsorption of the cationic layer of PAH and the anionic layer of oxygen-containing GO through electrostatic and/or hydrophobic interactions. Then, the GO species were chemically reduced by a strong reducing agent, NaBH4. The structural morphology and electrochemical properties of the as-prepared graphene-based multilayer LBL composite electrodes were thoroughly characterized by techniques such as ultraviolet visible (UV-vis) spectroscopy, high-resolution X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Raman spectroscopy, and cyclic voltammetry. Combined with differential pulse anodic stripping voltammetry (DPASV), the obtained –NH2 functional group modified nanocomposite electrodes with highly ordered multilayer superconductive graphene showed improved performance for trace detection of heavy metal ions such as Cu(II), resulting in sensitive electrochemical sensors. A linear dynamic range from 0.5 to 50 μM for Cu(II) was obtained under optimized conditions with a relatively low detection limit (S/N = 3) of around 0.35 μM. Our results provide valuable insight for the facile design of highly ordered graphene nanostructures with specific functionality of interest in a vast range, leading to a versatile nanoplatform for environmental or biomedical applications.