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The development of high-performance solid-polymer electrolytes (SPEs) is a key to the practical application of lithium metal batteries (LMBs). The use of two-dimensional (2D) inorganic nanofiller is an efficient way to build poly(ethylene oxide) (PEO)-based SPEs with high ionic conductivity and stability. Herein, a series of 2D oxygen vacancy-rich Co3O4-y−x (x = 1, 2 and 3) with well-defined 2D nanostructures, a high surface area and controllable oxygen vacancy contents (Co3O4-y) was synthesized via a facile self-assembly method and NaBH4 reduction. When the 2D Co3O4-y−x (x = 1, 2 and 3) nanosheets are introduced as nanofillers in PEO-based SPEs, they can interact with the PEO to form a three-dimensional (3D) PEO/Co3O4-y film with uniform Li+ distribution and vertical diffusion channels, as well as strong adsorption of NO3− from LiNO3 electrolyte salt at the defective sites. As a result, the PEO/Co3O4-y−2 film reached a high ionic conductivity of 4.9 × 10−5 S cm−1, high Li+ a transference number of 0.51 and a wide electrochemical window over 4.6 V at 80 °C. The PEO/Co3O4-y−2 film enables the Li||PEO/Co3O4-y−2||LiFePO4 cell to deliver a high reversible capacity of 117.7 mAh g−1 at 2 C and to maintain 126.7 mAh g−1 at 1 C after 250 cycles with an initial capacity retention of 87.9%. [ABSTRACT FROM AUTHOR]

The FeCoS2/rGO was synthesized by a one-step hydrothermal method, which has the advantages of environmental friendliness and low cost. Dense and homogeneous FeCoS2 nanodots are dispersed in the reduced graphene oxide flakes, which is beneficial to improve catalytic activity. Compared with FeS2/rGO, FeCoS2/rGO exhibits much higher initial discharge capacity and much better capacity retention ratio. The lower activation energy and the relatively narrow peak shape and small reduction/oxidation peak spacing show that FeCoS2/rGO have better catalytic activity than FeS2/rGO. It can be also confirmed by first-principles calculation that the adsorption energy of the Fe site (− 1.8334 eV) and the Co site (− 1.7539 eV) on the FeCoS2 surface is better than that of FeS2. So, the synergistic reaction of Fe and Co will adjust microregional electron density and change binding energy to polysulfides. [ABSTRACT FROM AUTHOR]

TaS2 as transition metal dichalcogenide (TMD) two-dimensional (2D) material has sufficient unstructured bonds and large inter-layer spacing, which highly supports transporting and absorbing mercury ions. The structural characterizations and simulation data show that an SPR sensor with high sensitivity can be obtained with a TaS2 material-modified sensitive layer. In this paper, the role of TaS2 nanoparticles in an SPR sensor was explored by simulation and experiment, and the TaS2 layer in an SPR sensor was characterized by SEM, elemental mapping, XPS, and other methods. The application range of structured TaS2 nanoparticles is explored, these TaS2 based sensors were applied to detect Hg2+ ions at a detection limit approaching 1 pM, and an innovative idea for designing highly sensitive detection techniques is provided. [ABSTRACT FROM AUTHOR]