Layered transition metal oxides are the most important cathode materials for Li/Na/K ion batteries. Suppressing undesirable phase transformations during charge-discharge processes is a critical and fundamental challenge towards the rational design of high-performance layered oxide cathodes. Here we report a shale-like Na_xMnO₂ (S-NMO) electrode that is derived from a simple but effective water-mediated strategy. This strategy expands the Na⁺ layer spacings of P2-type Na_0.67MnO₂ and transforms the particles into accordion-like morphology. Therefore, the S-NMO electrode exhibits improved Na⁺ mobility and near-zero-strain property during charge-discharge processes, which leads to outstanding rate capability (100 mAh g⁻¹ at the operation time of 6 min) and cycling stability (>3000 cycles). In addition, the water-mediated strategy is feasible to other layered sodium oxides and the obtained S-NMO electrode has an excellent tolerance to humidity. This work demonstrates that engineering the spacings of alkali-metal layer is an effective strategy to stabilize the structure of layered transition metal oxides.

Atomically thin ferromagnetic (FM) films were recently prepared by mechanical exfoliation of bulk FM semiconductor ${\mathrm{Cr}}_2{\mathrm{Ge}}_2{\mathrm{Te}}_6$. They provide a platform to explore novel two-dimensional (2D) magnetic phenomena, and they offer exciting prospects for new technologies. By performing systematic ab initio density functional calculations, here we study two relativity-induced properties of these 2D materials (monolayer, bilayer, and trilayer as well as bulk), namely magnetic anisotropy energy (MAE) and magneto-optical (MO) effects. Competing contributions of both magnetocrystalline anisotropy energy (C-MAE) and magnetic dipolar anisotropy energy (D-MAE) to the MAE are computed. The calculated MAEs of these materials are large, being on the order of $\sim 0.1$ meV/Cr. Interestingly, we find that out-of-plane magnetic anisotropy is preferred in all the systems except the monolayer, where in-plane magnetization is favored because here the D-MAE is larger than the C-MAE. Crucially, this explains why long-range FM order was observed in all the few-layer ${\mathrm{Cr}}_2{\mathrm{Ge}}_2{\mathrm{Te}}_6$ except the monolayer because the out-of-plane magnetic anisotropy would open a spin-wave gap and thus suppress magnetic fluctuations so that long-range FM order could be stabilized at finite temperature. In the visible frequency range, large Kerr rotations up to $\sim 2.2^{\circ }$ in these materials are predicted, and they are comparable to that observed in famous MO materials such as PtMnSb and ${\mathrm{Y}}_3{\mathrm{Fe}}_5{\mathrm{O}}_{12}$. Moreover, they are $\sim 100$ times larger than that of $3d$ transition metal monolayers deposited on Au surfaces. Faraday rotation angles in these 2D materials are also large, being up to $\sim {120}^{\circ }/\mu \mathrm{m}$, and they are thus comparable to the best-known MO semiconductor ${\mathrm{Bi}}_3{\mathrm{Fe}}_5{\mathrm{O}}_{12}$. These findings thus suggest that with large MAE and MO effects, atomically thin ${\mathrm{Cr}}_2{\mathrm{Ge}}_2{\mathrm{Te}}_6$ films would have potential applications in novel magnetic, MO, and spintronic nanodevices.

It is demonstrated that Sr ₅ (PO ₄ ) ₃ Cl:Eu ²⁺ blue-emitting phosphor features good thermal ability, high color purity and is a suitable blue-emitting candidate for the application in near-UV w-LEDs.

Ru _0.01 Ti _0.99 Nb ₂ O ₇ , with a much larger capacity than Li ₄ Ti ₅ O ₁₂ , fulfils the requirements of high power and energy density for electric vehicles.

A Li₂FeSiO₄/C composite material has been prepared via a solution-polymerization approach. The composite is characterized by X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and superconducting quantum interference device (SQUID). The electrochemical performance of the Li₂FeSiO₄ is greatly enhanced and the initial discharge capacity is ∼220 mA h g⁻¹, when it is cycled between 1.5–4.8 V. This indicates that more than one lithium ion can be extracted out of the Li₂FeSiO₄ lattice. At high current densities, the Li₂FeSiO₄/C also exhibits excellent rate capability and cycling stability. This indicates that it is a very promising cathode material for next generation lithium-ion batteries.