Morphology-Evolved Succulent-like FeCo Microarchitectures with Magnetic Configuration Regulation for Enhanced Microwave Absorption.

The regulation of magnetic configuration through diverse morphologies to achieve a rapid magnetic response has attracted considerable academic favor on account of the unique application prospects in various fields. Herein, porous FeCo alloys with morphology evolved from spheres to succulent-like microstructures are successfully constructed via a facile hydrothermal reaction-hydrogen reduction synthetic strategy. A multiple balance/competition mechanism is proposed, including the coexistence of the dissolution-precipitation balance of hydroxides and the dissociation-stability balance of coordination compounds, the Fe3+-Co2+ competition, and the precipitation-coordination reaction contest. As the morphology evolves to a succulent-like assembly, the multidomain features with a stable combination of vortex states and the violent motion of magnetic vectors contribute to the improvement of magnetic storage capacity and loss capability, which are evidenced by the off-axis electron holography and micromagnetic simulation. Consequently, the succulent-like FeCo exhibits enhanced permeability and microwave absorption performance. The effective absorption bandwidth reaches 5.68 GHz, and the maximum reflection loss is elevated to -53.81 dB. This work sheds considerable insight into the microstructure regulation with an application in microwave absorption and offers guidance in research for the topological magnetic configuration and dynamic response mechanism of magnetic alloys.

Atomic Short-Range Order in a Cation-Deficient Perovskite Anode for Fast-Charging and Long-Life Lithium-Ion Batteries.

Perovskite-type oxides are widely used for energy conversion and storage, but their rate-inhibiting phase transition and large volume change hinder the applications of most perovskite-type oxides for high-rate electrochemical energy storage. Here, it is shown that a cation-deficient perovskite CeNb3 O9 (CNO) can store a sufficient amount of lithium at a high charge/discharge rate, even when the sizes of the synthesized particles are on the order of micrometers. At 60 C (15 A g-1 ), corresponding to a 1 min charge, the CNO anode delivers over 52.8% of its capacity. In addition, the CNO anode material exhibits 96.6% capacity retention after 2000 charge-discharge cycles at 50 C (12.5 A g-1 ), indicating exceptional long-term cycling stability at high rates. The excellent cycling performance is attributed to the formation of atomic short-range order, which significantly prevents local and long-range structural rearrangements, stabilizing the host structure and being responsible for the small volume evolution. Moreover, the extremely high rate capacity can be explained by the intrinsically large interstitial sites in multiple directions, intercalation pseudocapacitance, atomic short-range order, and cation-vacancy-enhanced 3D-conduction networks for lithium ions. These structural characteristics and mechanisms can be used to design advanced perovskite electrode materials for fast-charging and long-life lithium-ion batteries.

Fluorescence-enhanced Cs4 PbBr6 /CsPbBr3 composites films synthesized by double-films solid phase reaction method.

Due to indispensable ligands, polluted organic solution, or complex vapour deposition, stable CsPbBr3 film is hard to be prepared directly using a simple and environmentally friendly method. To improve the stability of CsPbBr3 film and its synthesis methods, the double-films solid phase reaction was developed, and Cs4 PbBr6 /CsPbBr3 composites were designed. Although the synthesized particle had a size of 2-5 µm, much larger than that of quantum dots, in ambient conditions the composites films still showed good photoluminescence properties, with the highest photoluminescence quantum yield of 80%. It had good stability against air, temperature and humidity, and even had interesting fluorescence-enhanced phenomenon after about 4 days.

Eco-Friendly Strategy To Improve Durability and Stability of Zwitterionic Capping Ligand Colloidal CsPbBr3 Nanocrystals.

Long-chain zwitterionic ligands have been demonstrated to greatly improve the chemical durability of colloidal CsPbBr3 nanocrystals (NCs) by the chelate effect. However, Br sources are toxic, and the reaction is so dynamic that it is hard to control the size of the crystal. We propose an eco-friendly strategy to improve the chemical durability of colloidal CsPbBr3 NCs. Nontoxic, inexpensive, and directly available benzoyl bromine was used as the Br source, and tri-n-octylphosphine oxide was used as the adjuvant to control the reaction kinetics. Uniform, monodispersed NCs with a size of ∼11 nm were obtained. They had high photoluminescence quantum yields (PLQYs) of above 95% and, especially, showed strong stability against attack by polar solvents. The PLQY remained 80% even after 12 cycles of purification. Furthermore, after 24 h of continuous radiation by 405 nm laser, the photoluminescence (PL) intensity showed negligible decrease, and the wavelength and full width at half-maximum of PL had no significant change.