Ultrafine FeF₃·0.33H₂O Nanocrystal-Doped Graphene Aerogel Cathode Materials for Advanced Lithium-Ion Batteries

FeF3 has been extensively studied as an alternative positive material owing to its superior specific capacity and low cost, but the low conductivity, large volume variation, and slow kinetics seriously hinder its commercialization. Here, we propose the in situ growth of ultrafine FeF3·0.33H2O NPs on a three-dimensional reduced graphene oxide (3D RGO) aerogel with abundant pores by a facile freeze drying process followed by thermal annealing and fluorination. Within the FeF3·0.33H2O/RGO composites, the three-dimensional (3D) RGO aerogel and hierarchical porous structure ensure rapid diffusion of electrons/ions within the cathode, enabling good reversibility of FeF3. Benefiting from these advantages, a superior cycle behavior of 232 mAh g–1 under 0.1C over 100 cycles as well as outstanding rate performance is achieved. These results provide a promising approach for advanced cathode materials for Li-ion batteries

Mo-Doped Ni₃S₂ Nanosheet Arrays for Overall Water Splitting

Designing effective and low-cost bifunctional electrocatalysts for the alkaline hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is essential to achieve green development of the hydrogen economy. Herein, we have developed Mo-doped Ni3S2 nanosheet array catalysts with excellent electrochemical properties. Only 85 mV (HER) and 230 mV (OER) overpotentials are required under alkaline conditions at 10 mA cm–2 and remain undegraded for 100 h. In addition, it only required 1.52 V at 10 mA cm–2 in an alkaline electrolyzer, and it remained unchanged for more than 100 h in stability tests, outperforming most reported electrocatalysts. Experiments and density functional theory (DFT) calculations confirmed that the doping of Mo could expose more active sites of Ni3S2 and optimize the adsorption free energy of the intermediate, which in turn improves its intrinsic activity. This work reveals the key role of Mo in Ni3S2 electrocatalytic performance enhancement at the atomic scale

Mapping the Radiative and the Apparent Nonradiative Local Density of States in the Near Field of a Metallic Nanoantenna

We present a novel method to extract the various contributions to the photonic local density of states from near-field fluorescence maps. The approach is based on the simultaneous mapping of the fluorescence intensity and decay rate and on the rigorous application of the reciprocity theorem. It allows us to separate the contributions of the radiative and the apparent nonradiative local density of states to the change in the decay rate. The apparent nonradiative contribution accounts for losses due to radiation out of the detection solid angle and to absorption in the environment. Data analysis relies on a new analytical calculation, and does not require the use of numerical simulations. One of the most relevant applications of the method is the characterization of nanostructures aimed at maximizing the number of photons emitted in the detection solid angle, which is a crucial issue in modern nanophotonics

Mapping the Radiative and the Apparent Nonradiative Local Density of States in the Near Field of a Metallic Nanoantenna

We present a novel method to extract the various contributions to the photonic local density of states from near-field fluorescence maps. The approach is based on the simultaneous mapping of the fluorescence intensity and decay rate and on the rigorous application of the reciprocity theorem. It allows us to separate the contributions of the radiative and the apparent nonradiative local density of states to the change in the decay rate. The apparent nonradiative contribution accounts for losses due to radiation out of the detection solid angle and to absorption in the environment. Data analysis relies on a new analytical calculation, and does not require the use of numerical simulations. One of the most relevant applications of the method is the characterization of nanostructures aimed at maximizing the number of photons emitted in the detection solid angle, which is a crucial issue in modern nanophotonics