The exploration of high-performance dielectric ceramics with dielectric constants lower than 10 is of great significance for the next generation of wireless communication. In this study, we reported the Yb₂Si₂O₇ (YSO) dielectric ceramics synthesized using a facile solid-state reaction technique. X-ray diffraction (XRD) and transmission electron microscopy (TEM) characterization confirmed that YSO ceramics had a monoclinic structure. At a sintering temperature of 1500 °C, the sintered sample reached a maximum relative density of 96% and demonstrated the best dielectric properties: dielectric constant (ε_r) = 7.57, Q×f = 78,645 GHz (Q is quality factor, and f is the resonant frequency of 13.5 GHz), andtemperature coefficient of the resonant frequency (τ_f) = −13.5 ppm/°C. Moreover, Raman analysis revealed that the Si–O bond dominated the lattice vibration, and the full width at half maximum (FWHM) of the strong peak at 922 cm⁻¹ was inversely proportional to the Q×f value. According to the Phillips–van Vechten–Levine (P–V–L) theory, the values of Q×f and τ_f are affected primarily by the Si–O bond, while ε_r is influenced mainly by the Yb–O bond. YSO ceramics demonstrated excellent dielectric properties in the terahertz band (ε_r = 8.13, Q×f = 112,758 GHz), making them promising candidates for future applications in the terahertz band.

Garnet-type Li₇La₃Zr₂O₁₂ (LLZO) is one of the most promising solid-state electrolytes (SSEs). However, the application of LLZO is limited by structural instability, low ionic conductivity, and poor lithium stability. To obtain a garnet-type solid electrolyte with a stable structure and high ionic conductivity, a series of TaCe co-doping cubic Li_6·4La₃ZrTa_0.6CeO₁₂ (LLZTCO, x = 0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, 0.30) electrolytes were successfully synthesized through conventional solid-phase method. The Ta⁵⁺ doping can introduce more lithium vacancies and effectively maintain the stability of the cubic phase. The Ce⁴⁺ with a larger ionic radius is introduced into the lattice to widen the Li⁺ migration bottleneck size, which significantly increased the ionic conductivity to 1.05 × 10⁻³ S/cm. It also shows excellent stability to lithium metal by the optimization of Li⁺ transport channel. Li||LLZTCO||Li symmetric cells can cycle stably for more than 6 000 h at a current density of 0.1 mA/cm² without any surface modifications. The commercialization potential of LLZTCO samples in all solid-state lithium batteries (ASSLBs) is confirmed by the prepared LiFePO₄||LLZTCO||Li cells with a capacity retention rate of 98% after 100 cycles at 0.5C. This new co-doping method presents a practical solution for the realization of high-performance ASSLBs.

Sr_0.7Bi_0.2TiO₃ (SBT) by increasing the proportion and size of polar nano-region. Meanwhile, the BDS remains a high level with x ≤ 0.38 attributed to the addition of KBT with a large band gap. As a result, the 0.62SBT-0.38KBT exhibits a high energy storage density of 2.21 J/cm³ with high η of 91.4% at 220 kV/cm and superior temperature stability (−55 ~ 150 °C), frequency stability (10 ~ 500 Hz) and fatigue resistance (10⁵ cycles). Moreover, high pulsed discharge energy density (1.81 J/cm³), high power density (49.5 MW/cm³) and great thermal stability (20 ~ 160 °C) are achieved in 0.62SBT-0.38KBT. Based on these excellent properties, the 0.62SBT-0.38KBT are suitable for pulsed power systems. This work provides a novel strategy and systematic study for improving energy storage properties of SBT.