Search

Nanowhisker-like Cu3(HHTP)2 composed of neat arrays grown on a copper foam is rationally designed and prepared using Cu(OH)2 nanowire arrays as a self-sacrifice template. Benefiting from the good conductivity of Cu3(HHTP)2 and an ordered array structure, the optimized Cu3(HHTP)2@CF-3 electrode exhibits high area capacity, good rate performance and cyclic stability. [ABSTRACT FROM AUTHOR]

Hollow porous AuAg nanospheres (AuAg HPNSs) were obtained through a simple solvothermal synthesis, complemented by a dealloying strategy. The hollow interior, open pore voids, and integral interconnected skeleton shell in AuAg HPNSs are beneficial for providing sufficient electrolyte diffusion and contacts, abundant active sites, and efficient electron transport. This specific structure and the favorable alloy synergism contribute to the superior electrocatalytic activity toward dopamine (DA) and acetaminophen (AC). AuAg HPNSs show high sensitivity, good selectivity, excellent sensing durability, and outstanding repeatability for amperometric assays of AC and DA. In particular, the AuAg-based sensors achieve effective ultrasensitive simultaneous analyses of AC and DA, exhibiting the characteristics of the wide linear range and low detection limit. With their prominent electrocatalytic activity and simple preparation methods, AuAg HPNSs present broad application prospects for constructing a highly responsive electrochemical sensing system. [ABSTRACT FROM AUTHOR]

Zinc-ion capacitors (ZICs), combining the merits of both high-energy zinc-ion batteries and high-power supercapacitors, are known as high-potential electrochemical energy storage (EES) devices. However, the research on ZICs still faces many challenges because of the lack of appropriate cathode materials with robust crystal structures and rich channels for stable and fast Zn2+ ion transport. In this study, we synthesized a robust, conductive, two-dimensional metal–organic framework (MOF) material, zinc-benzenehexathiolate (Zn-BHT), and investigated its electrochemical performance for zinc storage. Zn2+ ions could insert into/extricate from the host structure with a high diffusion rate, enabling the Zn-BHT cathode to exhibit a surface-controlled charge storage mechanism. Due to its unique structure, Zn-BHT exhibited a good reversible discharge capacity approaching 90.4 mAh g−1 at 0.1 A g−1, as well as a desirable rate capability and good cycling performance. In addition, a ZIC device was fabricated using the Zn-BHT cathode and a polyaniline-derived porous carbon (PC) anode, which depicted a high working voltage of up to 1.8 V and a high energy density of ~37.2 Wh kg−1. This work shows that conductive MOFs are high-potential electrode materials for ZICs and provide new enlightenment for the development of electrode materials for EES devices. [ABSTRACT FROM AUTHOR]

Recently, silicon has been considered one of the preferred materials for the anodes of next-generation high-energy-density Li-ion batteries due to its advantages of high specific capacity, low working voltage, and abundant reserves. However, the huge volume change and poor electrical conductivity of silicon anodes during the lithiation and de-lithiation process seriously affect their practical application. Herein, honeycomb porous silicon is synthesized by a modified Stöber method and magnesium thermal reduction, which avoids using toxic gases (such as silane) in the traditional preparation of commercial nano-silicon. Moreover, the honeycomb porous structure can effectively alleviate the volume expansion during the charge/discharge process and agglomeration behavior of nano-silicon. Therefore, thanks to its unique structural merits, the honeycomb porous silicon anode is endowed with a reversible specific capacity of 824.1 mA h g−1 after 100 cycles at 0.5 A g−1 and 679.2 mA h g−1 even at an ultrahigh current density of 1.0 A g−1 after an extended cycling period of 200 cycles, which is almost twice that of commercial nano-silicon. More importantly, this finding offers promising advancements in designing silicon anodes in energy storage. [ABSTRACT FROM AUTHOR]

Carbonized polymer dots (CPDs) have received much attention in recent years owing to their cost‐effective synthesis, high resistance to photobleaching, environmental friendliness, and excellent biocompatibility. However, the aggregation‐induced fluorescence quenching is a great obstacle to its applications. In this work, the highly fluorescent CPDs are prepared by a facile hydrothermal method assisted by polyethylene glycol (PEG) as the surface passivation agent, where phthalic acid and ethylenediamine are used as carbon and nitrogen source, respectively. Meanwhile, five types of PEG species are applied to prepare five CPDs to investigate PEG on optical properties of the resultant CPDs, among which the best quantum yield reaches 57.0 %. The promising applications of CPDs as fluorescent inks, sensors, light emitting diodes, and UV shielding films have been demonstrated. Overall, our contribution here develops a facile and accessible route for the synthesis of CPDs and further demonstrates its versatile applications. [ABSTRACT FROM AUTHOR]

The orthorhombic CuNb2O6 (O–CNO) is established as a competitive anode for lithium‐ion capacitors (LICs) owing to its attractive compositional/structural merits. However, the high‐temperature synthesis (>900 °C) and controversial charge‐storage mechanism always limit its applications. Herein, we develop a low‐temperature strategy to fabricate a nano‐blocks‐constructed hierarchical accordional O–CNO framework by employing multilayered Nb2CTx as the niobium source. The intrinsic stress‐induced formation/transformation mechanism of the monoclinic CuNb2O6 to O–CNO is tentatively put forward. Furthermore, the integrated phase conversion and solid solution lithium‐storage mechanism is reasonably unveiled with comprehensive in(ex) situ characterizations. Thanks to its unique structural merits and lithium‐storage process, the resulted O–CNO anode is endowed with a large capacity of 150.3 mAh g−1 at 2.0 A g−1, along with long‐duration cycling behaviors. Furthermore, the constructed O–CNO‐based LICs exhibit a high energy (138.9 Wh kg−1) and power (4.0 kW kg−1) densities with a modest cycling stability (15.8% capacity degradation after 3000 consecutive cycles). More meaningfully, the in‐depth insights into the formation and charge‐storage process here can promote the extensive development of binary metal Nb‐based oxides for advanced LICs. [ABSTRACT FROM AUTHOR]

Na3V2(PO4)3 (NVP), as a great potential cathode candidate for Na-ion batteries (NIBs), has attracted enormous interest due to its three-dimensional (3D) large open framework for convenient Na+ transport, yet its practical application is still limited by its inferior electron conductivity and sluggish Na+ diffusion kinetics. Herein, the tiny Cr doped hierarchical NVP micro-flower cathodes (i.e., Na3V2−xCrx(PO4)3@C, x ≤ 0.1), which are self-assembled with single-crystal nanoflake subunits in-situ coated with carbon nano-shell, are designed and fabricated via a scalable avenue. The optimized cathode, i.e., Na3V1.94Cr0.06(PO4)3@C (NVCP-6), was endowed with more electro-active Na(2) sites and higher electronic/ionic conductivity for efficient sodium storage. Benefiting from these competitive merits, the NVCP-6, when evaluated as a cathode towards NIBs, exhibits an ultrahigh-rate capability of 99.8 mAh·g−1 at 200 C and superior stability of 82.2% over 7300 cycles at 50 C. Furthermore, the NVCP-6 based full NIBs display remarkable electrochemical properties in terms of both high-rate capacities and long-duration cycling properties at different temperatures (−20–50 °C). The contribution, i.e., the design of "four ounces can move a thousand pounds", here will promote the practical industrial application of NVP towards advanced NIBs. [ABSTRACT FROM AUTHOR]

Focused exploration of earth‐abundant and cost‐efficient non‐noble metal electrocatalysts with superior hydrogen evolution reaction (HER) performance is very important for large‐scale and efficient electrolysis of water. Herein, a sandwich composite structure (designed as MS‐Mo2C@NCNS) of β‐Mo2C hollow nanotubes (HNT) and N‐doped carbon nanosheets (NCNS) is designed and prepared using a binary NaCl–KCl molten salt (MS) strategy for HER. The temperature‐dominant Kirkendall formation mechanism is tentatively proposed for such a three‐dimensional hierarchical framework. Due to its attractive structure and componential synergism, MS‐Mo2C@NCNS exposes more effective active sites, confers robust structural stability, and shows significant electrocatalytic activity/stability in HER, with a current density of 10 mA cm−2 and an overpotential of only 98 mV in 1 M KOH. Density functional theory calculations point to the synergistic effect of Mo2C HNT and NCNS, leading to enhanced electronic transport and suitable adsorption free energies of H* (ΔGH*) on the surface of electroactive Mo2C. More significantly, the MS‐assisted synthetic methodology here provides an enormous perspective for the commercial development of highly active non‐noble metal electrocatalysts toward efficient hydrogen evolution. [ABSTRACT FROM AUTHOR]