No abstract

Porous copper zinc tin sulfide (CZTS) thin film was prepared via a solvothermal approach. Compared with conventional dye-sensitized solar cells (DSSCs), double junction photoelectrochemical cells using dye-sensitized n-type TiO(2) (DS-TiO(2)) as the photoanode and porous p-type CZTS film as the photocathode shows an increased short circuit current, external quantum efficiency and power conversion efficiency.

Aqueous zinc-ion batteries (ZIBs) are low cost with a promising theoretical capacity and inherent safety, and thus have drawn increasing attention as prospective energy storage devices in large-scale energy storage systems. However, severe dendrite growth and side reaction problems hinder the practical application of ZIBs. Here, molecular sieves with ordered mesoporous channels are constructed to tailor the local electrolyte solvation structure on the zinc surface. Different high-concentration solvation structures can be realized by adjusting the pore diameter of the molecular sieve, and the optimal pore geometry is a mesoporous channel with a diameter of 2.5 nm that induces the formation of a locally concentrated electrolyte and affords a lower Zn 2+ de-solvation energy in Mobil composition of matter number 41 (MCM41). The resulting MCM41-Zn anode exhibits high cycling stability for Zn stripping/plating under different current densities (over 1800 h at 1 mA cm -2 , 1 mAh cm -2 , and 2200 h at 5 mA cm -2 , 1 mAh cm -2 ). Moreover, the CaV 8 O 20 •nH 2 O//MCM41-Zn full cell shows a high capacity of 274.2 mAh g −1 and a long lifespan (no capacity decay after 1000 cycles at 4 A g -1 ).

Pre‐intercalation of metal ions into vanadium oxide is an effective strategy for optimizing the performance of rechargeable zinc‐ion battery (ZIB) cathodes. However, the battery long‐lifespan achievement and high‐capacity retention remain a challenge. Increasing the electronic conductivity while simultaneously prompting the cathode diffusion kinetics can improve ZIB electrochemical performance. Herein, N‐doped vanadium oxide (N‐(Zn,en)VO) via defect engineering is reported as cathode for aqueous ZIBs. Positron annihilation and electron paramagnetic resonance clearly indicate oxygen vacancies in the material. Density functional theory (DFT) calculations show that N‐doping and oxygen vacancies concurrently increase the electronic conductivity and accelerate the diffusion kinetics of zinc ions. Moreover, the presence of oxygen vacancies substantially increases the storage sites of zinc ions. Therefore, N‐(Zn,en)VO exhibits excellent electrochemical performance, including a peak capacity of 420.5 mA h g−1 at 0.05 A g−1, a high power density of more than 10 000 W kg−1 at 65.3 Wh kg−1, and a long cycle life at 5 A g−1 (4500 cycles without capacity decay). The methodology adopted in our study can be applied to other cathodic materials to improve their performance and extend their practical applications.

Rechargeable aqueous zinc‐ion batteries (ZIBs) have recently been comprehensively studied because of metal zinc (Zn) unique properties. However, the problems of metal zinc anode in ZIBs, namely, dendrite formation and side reactions, seriously shorten the cycling lifetimes and limit the coulombic efficiencies. Here, the tin (Sn) layer with a three‐dimensional nano‐channeled structure is decorated on zinc metal via a facile in situ substitution reaction, constructing the Sn modified Zn (Sn‐Zn) anode for high‐performance ZIBs. Multiscale investigation techniques, especially micro‐CT, are used to investigate the inhibition of zinc dendrites. In addition, the induction mechanism of Zn by Sn is also elaborately investigated. The designed Sn‐Zn anode can alleviate zinc dendrite growth and ensure long‐life stability. This work brings exciting new possibilities for the realization of industrial aqueous zinc‐ion batteries and provides new insights for the rational deposition of the Zn metal anodes.

Mg2MnO4 nanoparticles with cubic spinel structure were synthesized by the sol-gel method using polyvinyl alcohol (PVA) as a chelating agent. X-ray powder diffraction, infrared spectrum (IR), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize the crystalline phase and particle size of as-synthesized nanoparticles. The electronic structure of Mg2MnO4 spinel was studied by X-ray photoelectron spectroscopy (XPS). The results showed that pure cubic Mg2MnO4 spinel nanoparticles were obtained when the annealing temperature was 500–700 °C. The samples had a porous-spongy structure assembled by nanoparticles. XPS studies indicated that Mg2MnO4 nanoparticles were mixed spinel structures and the degree of cation inversion decreased with increasing annealing temperature. Furthermore, the performance of Mg2MnO4 as lithium anode material was studied. The results showed that Mg2MnO4 samples had good cycle stability except for the slight decay in the capacity at 50 cycles. The coulombic efficiency (ratio of discharge and charge capacity) in most cycles was near 100%. The sample annealed at 600 °C exhibited good electrochemical properties, the first discharge capacity was 771.5 mAh/g, and the capacity remained 340 mAh/g after 100 cycles. The effect of calcination temperature on the charge–discharge performance of the samples was studied and discussed.

Lithium metal is a promising candidate for the high‐energy‐density batteries. However, the high instability of Li against air and dendrite growth during cycling are the key challenges hindering the commercial application of the Li metal battery (LMB). In this study, an organic/inorganic hybrid artificial solid electrolyte interphase (SEI) is introduced on Li surface via dipping Li into 0.1 m zinc trifluoromethanesulfonate solution for 1 min. The key components that endow stability to Li in air for 4 h are analyzed via theoretical calculations. The results confirm that LiF and Zn absorbed with CF3 organic groups can reduce the absorption energy of O2, H2O, and CO2 on Li, thereby limiting the reaction of Li with ambient air. The Li anode with an organic/inorganic hybrid SEI cycles over 600 h at 0.5 mA cm−2 in symmetric cell and 500 cycles in a Li||LiFePO4 full cell, after exposure to ambient air for 4 h. Moreover, the organic/inorganic SEI can facilitate the Li+ transformation and suppress the growth of Li dendrites. The designed air‐stable and dendrite‐free Li metal anodes are promising for practical applications of LMBs.

No abstract