**Abstract**

An overview of ferroelectric glass ceramics, some literature review and some of the important previous studies were focused in this chapter. Nanocrystalline glass–ceramics containing ferroelectric perovskite-structured phases have been included. All modified glasses having ferroelectric ceramics which prepared by different methods are discussed, that producing nanocrystalline glass–ceramics. Then particular tested to their use as dielectric energy storage materials. These materials exhibit promising dielectric properties, indicating good potential for high energy density capacitors as a result of their nanocrystalline microstructures. The results of the analysis are summarised in this chapter to provide an overview of the energy storage characteristics of the different materials produced during the study.

**Keywords:** ferroelectric, glass-ceramics, BaTiO3, KNN, energy storage, crystallisation
