Direct Ink Writing of Bi₂SiO₅-Based Ferroelectric Materials

in recent years, Bi₂SiO₅ has attracted widespread attention for its excellent ferroelectric properties and has become a research hotspot for low-cost and environmentally friendly ferroelectric materials. However, traditional molding technology struggles to meet the demands for high precision and complex structures. This paper utilizes direct writing technology to rapidly prepare bulk ferroelectric materials based on Bi₂SiO₅, laying the foundation for manufacturing devices with complex structures. By studying the rheology of slurries with different PVA contents and solid contents, the optimal preparation conditions were established. A systematic study of direct writing molding process parameters and other factors was conducted, and performance tests demonstrated the ferroelectric properties and energy storage characteristics of Bi₂SiO₅-based bulk materials at different sintering temperatures. The optimal slurry formulation was determined to be: 73.9 wt.% solid content, 3.2 wt.% polyvinyl alcohol, and 0.5 wt.% each of polyethylene glycol and glycerol. The optimal direct writing molding parameters for Bi₂SiO₅ ceramic slurry were determined to be: printing nozzle inner diameter of 0.41 mm, substrate material of filter paper, printing speed of 20 mm/s, and layer height set to 0.41 mm. Bi₂SiO₅ green bodies with close-packed and wood-pile structures were formed at line spacings of 0.50 mm and 0.80 mm, respectively. The Bi₂SiO₅-based bulk ferroelectric materials prepared by direct writing molding exhibited low ρ and εr values, and slender hysteresis loops. After sintering at 620°C, the material showed high energy storage density (0.0470 J·cm^-3) and energy storage efficiency (89.59%). However, when the temperature was increased to 700°C, the material essentially lost its ferroelectricity, resulting in the lowest energy storage density, but still maintained very high energy storage efficiency (98.54%). These results provide important information for the direct writing preparation of Bi₂SiO₅ ferroelectric materials and highlight their application potential in the energy storage field.