Metallic lithium (Li) is a promising anode material for next-generation rechargeable batteries. However, the dendrite growth of Li and repeated formation of solid electrolyte interface during Li plating and stripping result in low Coulombic efficiency, internal short circuits, and capacity decay, hampering its practical application. In the development of stable Li metal anode, the current collector is recognized as a critical component to regulate Li plating. In this work, a lithiophilic Cu-CuO-Ni hybrid structure is synthesized as a current collector for Li metal anodes. The low overpotential of CuO for Li nucleation and the uniform Li ion flux induced by the formation of Cu nanowire arrays enable effective suppression of the growth of Li dendrites. Moreover, the surface Cu layer can act as a protective layer to enhance structural durability of the hybrid structure in long-term running. As a result, the Cu-CuO-Ni hybrid structure achieves a Coulombic efficiency above 95% for more than 250 cycles at a current density of 1 mA cm and 580 h (290 cycles) stable repeated Li plating and stripping in a symmetric cell.
Herein, we present a multifunctional chip based on surface-enhanced Raman scattering (SERS) that effectively captures, discriminates, and inactivates pathogenic bacteria. The developed SERS chip is made of a silicon wafer decorated with silver nanoparticles and modified with 4-mercaptophenylboronic acid (4-MPBA). It was prepared in a straightforward manner by chemical reduction assisted by hydrogen fluoride etching, followed by the conjugation of 4-MPBA through AgS bonds. The dominant merits of the fabricated SERS chip include excellent reproducibility with a relative standard deviation (RSD) value smaller than 11.0 %, adaptable bacterial-capture efficiency (ca. 60 %) at low concentrations (500-2000 CFU mL(-1) ), a low detection limit (down to a concentration of 1.0×10(2) cells mL(-1) ), and high antibacterial activity (an antibacterial rate of ca. 97 %). The SERS chip enabled sensitive and specific discrimination of Escherichia coli and Staphylococcus aureus from human blood.
Nickel foam supported hierarchical mesoporous Zn-Ni-Co ternary oxide (ZNCO) nanowire arrays are synthesized by a simple two-step approach including a hydrothermal method and subsequent calcination process and directly utilized for supercapacitive investigation for the first time. The nickel foam supported hierarchical mesoporous ZNCO nanowire arrays possess an ultrahigh specific capacitance value of 2481.8 F g(-1) at 1 A g(-1) and excellent rate capability of about 91.9% capacitance retention at 5 A g(-1). More importantly, an asymmetric supercapacitor with a high energy density (35.6 Wh kg(-1)) and remarkable cycle stability performance (94% capacitance retention over 3000 cycles) is assembled successfully by employing the ZNCO electrode as positive electrode and activated carbon as negative electrode. The remarkable electrochemical behaviors demonstrate that the nickel foam supported hierarchical mesoporous ZNCO nanowire array electrodes are highly desirable for application as advanced supercapacitor electrodes.
Mesoporous Ni–Co–Mn hydroxide nanoflakes (NCMH) with excellent supercapacitive performance have been firstly prepared by facile and cost effective seed-assisted methods.
It is of essential importance to precisely probe mercury(II) (Hg(2+)) ions for environment-protection analysis and detection. To date, there still remain major challenges for accurate, specific, and reliable detection of Hg(2+) ions at subppt level. We herein employ gold nanoparticles (AuNPs) decorated silicon nanowire array (SiNWAr) as active surface-enhanced Raman scattering (SERS) substrates to construct a high-performance sensing platform assisted by DNA technology, enabling ultrasensitive detection of trace Hg(2+) in ∼64 min and with low sample consumption (∼30 μL). Typically, strong SERS signals could be detected when the single-stranded DNA structure converts to the hairpin structure in the presence of Hg(2+) ions, due to the formation of thymine (T)-Hg(2+)-T. As a result, Hg(2+) ions with a low concentration of 1 pM (0.2 ppt) can be readily discriminated, much lower than those (∼nM) reported for conventional analytical strategies. Water samples spiked with various Hg(2+) concentrations are further tested, exhibiting a good linear relationship between the normalized Raman intensities and the logarithmic concentrations of Hg(2+) ranging from 1 pM to 100 nM, with a correlation coefficient of R(2) = 0.998. In addition, such SERS sensor features excellent selectivity, facilely distinguishing Hg(2+) ions from various interfering substances. Moreover, this presented SERS sensor possesses good recyclability, preserving adaptable reproducibility during 5-time cyclic detection of Hg(2+). Furthermore, unknown Hg(2+) concentration in river water can be readily determined through our sensing strategy in accurate and reliable manners, with the RSD value of ∼9%.
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