<p>The dielectric glasses with efficient working in harsh conditions (at high temperatures &gt; 200&#xa0;°C) meet the growing demand for capacitive energy storage applications; furthermore, the enhancement of their energy storage performance is urgently needed. Herein, a novel glass composition (51-x)B₂O₃:7MgO:16V₂O₅:26Na₂O: xBaTiO₃; x = 0, 4, 8, 12, 16, and 20&#xa0;mol% is synthesized by the conventional melt quenching technique. The dielectric characteristics are investigated at high temperatures extending to 720&#xa0;K, and found to be enhanced by both BaTiO₃-incorporation and nanocrystallization. The nanocrystallization is performed on the glass containing 20&#xa0;mol% of BaTiO₃ at various temperatures, basing on its DSC profile. The XRD analysis confirms the amorphous nature and the crystallinity of investigated glasses and nanostructured glass-ceramics, respectively. A gradual increase is detected for the variation of glass transition temperature and crystallization temperature with the addition of barium titanate. The absorption of the studied glasses in the infrared region is attributed to the electronic transition of ions and increases with BaTiO₃ incorporation, indicating the conversion of V⁵⁺ to V⁴⁺ ions. However, the absorption coefficient of the understudy glasses is controlled by the transition of Ti³⁺ ions in the visible region and by the transition of Ti⁴⁺ and V⁵⁺ ions in the UV region. The effects of frequency, temperature, BaTiO₃ content, nanocrystallization, and annealing temperature on the dielectric parameters such as dielectric constant, dissipation factor, ac conductivity, and electric modulus are investigated. The BaTiO₃-incorporation and nanocrystallization not only improve the dielectric constant but also reduce the dielectric loss, which makes the synthesized glasses and glass-ceramics promising candidates for solid-state batteries, capacitor, and energy storage devices.</p>