Ceramic dielectrics are reported with superior energy storage performance for applications, such as power electronics in electrical vehicles. Recoverable energy density (Wrec) of ~ 4.55 J cm-3 with η~90% is achieved in a lead-free relaxor BaTiO3-0.06Bi2/3(Mg1/3Nb2/3)O3 ceramics at ~ 520 kV cm-1. These ceramics may be co-fired with Ag/Pd, which constitutes a major step forward towards their potential use in the fabrication of commercial multilayer ceramic capacitors. Compared to stoichiometric Bi(Mg2/3Nb1/3)O3 doped BaTiO3 (BT), A-site deficient Bi2/3(Mg1/3Nb2/3)O3 reduces the electrically heterogeneity of BT. Bulk conductivity differs from grain boundary only by one order of magnitude which, coupled with a smaller volume fraction of conducting cores due to enhanced diffusion of the dopant via A-site vacancies in the A-site sublattice, results in higher breakdown strength under electric field. This strategy can be employed to develop new dielectrics with improved energy storage performance.

The lattice stability and phonon response of Ti3C2Tx MXene at high pressure are important for understanding its mechanical and thermal properties fully. Here, we use in situ high hydrostatic pressure X-ray diffraction (XRD) and Raman spectroscopy to study the lattice deformation and phonon behavior of Ti3C2Tx MXene. XRD spectra indicate that no phase transformation occurs up to the pressure of 26.7 GPa. The elastic constant along a lattice parameter was calculated to be 378 GPa. In the Raman spectra obtained at high-pressure, the out-of-plane phonon modes (A1g at ~ 210, ~ 504, and ~ 711 cm−1) exhibit monotonic blueshifts with increasing pressure. The Grüneisen parameters of these three modes were calculated to be 1.08, 1.16, and 0.29, respectively. These results enrich the basic property data of Ti3C2Tx MXene and would benefit the further understanding of this novel material.

The Y₃MgAl₃SiO₁₂ ceramics with pure phase were successfully synthesized by solid‐state sintering reaction method for the first time. Their microwave dielectric properties were investigated as a function of sintering temperature. Their microstructure characteristics and ionic occupation sites of tetrahedral and octahedral units were characterized and analyzed by SEM& energy dispersive spectrometer (EDS) and Rietveld refinement of X‐ray powder diffraction data. Crystal structure of Y₃MgAl₃SiO₁₂ is isostructural to Y₃Al₅O₁₂ with a cubic garnet structure and space group of Ia‐3d, which contains YO₈ dodecahedra, (Mg/Al_oct)O₆ octahedral, and (Si/Al_tet)O₄ tetrahedral units. The Qf and ε_r values of different samples are strongly dependent on the distribution of grain sizes, grain sizes, and porosity. The samples sintered at 1550°C exhibit optimized microwave dielectric properties with relative permittivity (ɛ_r) of 10.1, Qf values of 57 340GHz (at 9.5 GHz), and τ_f values of −32 ppm/°C. Such properties indicate potential application of Y₃MgAl₃SiO₁₂ as microwave substrates.