As
a promising anode for aqueous batteries, Zn metal shows a number
of attractive advantages such as low cost, low redox potential, high
capacity, and environmental benignity. Nevertheless, the quick growth
of dendrites/protrusions on the “hostless” Zn anodes
not only enlarges batteries’ internal resistance but also causes
sudden shorting failure by piercing separators. Herein, we report
a novel heterogeneous seed method to guide the morphology evolution
of plated Zn. The heterogeneous seeds are sputtering-deposited quasi-isolated
nano-Au particles (Au-NPs) that enable a uniform and stable Zn-plating/stripping
process on the anodes. Tested on Zn|Zn symmetric cells, the Au-nanoparticle
(NP) decorated Zn anodes (NA-Zn) demonstrate much better cycling stability
than the bare ones (92 vs 2000 h). In NA-Zn|CNT/MnO2 batteries,
this heterogeneous seed prolongs the lifetime of the device from ∼480
cycles up to 2000 cycles. This work offers a facile and promising
Zn dendrite/protrusion suppressing route for the achievement of long-life
Zn-ion batteries.
In this article, pure phase metastable wurtzite Cu 2 ZnSnS 4 (CZTS) nanocrystals (NCs) were synthesized by a facile one-pot method. When pure 1dodecanethiol (DDT) was used as the solvent, two coexisting CZTS phases (wurtzite and kesterite) were found. When an increased amount of oleylamine (OAm) was added to DDT, kesterite CZTS disappeared gradually, and the asobtained CZTS NCs became smaller and more uniform. When 0.5 mL of OAm was added, rice-like pure phase metastable wurtzite CZTS NCs were obtained. The factors, including amount of OAm, reaction temperature, reaction time, and concentration of precursors, which influence the morphology, size, and monodispersity of CZTS NCs, were studied in detail. The results showed OAm played an important role in the formation of the final pure phase metastable wurtzite NCs. Time-dependent experiments were performed to observe the growth of CZTS NCs. The final CZTS NCs evolved from spherical-like Cu 2 S NCs through rhombuslike intermediate shaped NCs to rice-like pure wurtzite CZTS NCs. On the basis of the detailed time-dependent shape and elemental composition evolutions, a possible asynchronous doping growth and formation mechanism was proposed. The optical and electrical properties of the pure wurtzite CZTS NCs were also investigated. The band gap of the rice-like CZTS is about 1.49 eV, which approaches the optimum value for solar photoelectric conversion. Meanwhile, the current−voltage characteristics and Hall effect measurement of the wurtzite CZTS NCs films indicated that rice-like CZTS NCs favored the electronic transmission and thus may induce the generation of photocurrent. Thus, the obtained wurtzite CZTS NCs are more suitable for using as absorber layer in low cost solar cells.
frameworks (MOFs), synthesized by assembling metal nods with organic linkers, are highly ordered crystalline materials. MOFs have attracted much attention for applications in electrochemical sensors, because of their unique chemical and physical properties including ultrahigh porosity, large surface area, tunable structure, and high thermal and chemical stability. In particular, redox and catalytic active sites introduced by use of active metal ions and/or ligands endow MOFs with the functions required in electrochemical sensing. Moreover, precise chemical modification of functional molecules and immobilization with metal nanoparticles, carbon nanostructures, and biomolecules could promote their electrochemical performances. In this Review, we focus on recent progress achieved in MOF research with respect to general sensing principles and analytical performances of electrochemical sensors. The evaluation and challenges governing the detection of the assays are also discussed.
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