Lithium metal batteries (LMBs) have the potential to deliver a greater specific capacity than any commercially used lithium battery. However, excessive dendrite growth and low Coulombic efficiencies (CEs) are major hurdles preventing the commercialization of LMBs. In this study, two different salts, lithium difluorophosphate (LiDFP) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), are chosen for use in concentrated electrolytic systems. By mixing salts with vastly different cation–anion interaction energies, the ion solvation structures in the electrolyte can be modulated to enhance the physical/electrochemical properties and suppress Li dendrite growth in LMBs. Among the investigated electrolyte systems, 2.2 m LiDFP + 1.23 m LiTFSI in 1,2‐dimethoxyethane is proposed as a highly promising electrolyte system because of its high conductivity (6.57 mS cm−1), CE (98.3%), and the formation of an extremely stable solid–electrolyte interface layer. The bisalt electrolyte presented herein, as well as the associated concepts, provide a new avenue toward commercial LMBs.

Solar-driven semiconductor-based molecular hydrogen production is an ideal protocol for converting abundant solar energy to green fuel. However, this process suffers from costly semiconductor nanostructures, low efficiency, and poor stability. Here, we design a noble-metal-free photocatalyst, CdS-NiFe layered double hydroxide (LDH) nanocomposite, which is synthesized using the liquid-phase pulsed-laser ablation and hydrothermal method. The nanocomposite has a unique morphology of 2D-NiFe LDH nanosheets on 1D-CdS nanorods. The interfacial contact of heterostructures allows the efficient carrier transport and migration due to the appropriate potentials, which greatly reduce the recombination of carriers. It also provides a significant number of catalytically active sites for the hydrogen evolution reaction due to its thin and flexible nature and high specific surface area. The CdS/NiFe nanocomposite exhibits a hydrogen evolution rate of 72 mmol g–1 h–1, which is higher than reported nanocomposites of CdS-based cocatalyst nanostructures. We expect that the demonstrated method to form noble-metal-free CdS-based cocatalyst nanostructures and the utilization in photocatalytic hydrogen evolution reactions provide novel insights into developing cost-effective photocatalysts for hydrogen production.

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The optical properties of ZnS–AgIn5S8 quantum dots (QDs) with core/shell structures are examined to clarify the enhancement mechanism of the photoluminescence (PL) quantum yield (QY). Two types of QDs are synthesized by varying the concentration of zinc precursors, with alloyed-core (ZnS–AgIn5S8, ZAIS), inner-shell (ZnIn2S4, ZIS), and outer-shell (ZnS) structures, such as ZAIS/ZIS/ZnS and ZAIS/ZnS. Upon alloying/shelling processes from the preformed AgIn5S8 QDs, the evolution of the band gap energy indicates the formation of the solid solution of ZAIS. Due to the difference in the degree of alloying between ZAIS/ZIS/ZnS and ZAIS/ZnS QDs, the blue shift of PL, Stokes shift, and QY are different. The alloying/shelling processes improve the QY of the intrinsic defect states more effectively than the QY of the surface defect states, while the time-resolved studies suggest that the enhanced radiative rate of the intrinsic states is responsible for the improvement of the QY, in addition to the reduced nonradiative rate. In ZAIS/ZIS/ZnS QDs, the QY increases to 85%, which is attributed to the existence of the ZIS layer, as well as the reduced nonradiative states and the enhanced radiative states by the alloying/shelling processes. The ZIS layer mitigates the lattice strains and provides the appropriate levels of the electronic structures in the QDs, which further reduces the nonradiative rate and enhances the radiative rate, respectively, leading to the unprecedentedly high PL QY of ZAIS/ZIS/ZnS QDs.