Achieving high pulse charge–discharge energy storage properties and temperature stability of (Ba0.98-Li0.02La )(Mg0.04Ti0.96)O3 lead-free ceramics via bandgap and defect engineering

A novel dual priority strategy of strengthening charge compensation in A-site of perovskite structure and widening bandgap width was designed to prepare (Ba0.98-xLi0.02Lax)(Mg0.04Ti0.96)O3 (BLLMTx) ceramics, which can solve the conflict between polarization and breakdown strength, and improve the pulse energy storage performance of the BaTiO3-based system. As a result, ultrahigh discharge energy density of 3.98 J/cm3 and giant pulse power density of 321.6 MW/cm3 with current density of 2786.4 A/cm2 are obtained at 360 kV/cm for the (Ba0.94Li0.02La0.04)(Mg0.04Ti0.96)O3 (BLLMT0.04) ceramics with considerable fast discharge rate and outstanding temperature stability as well as cycle life, correlating with multi-ferroelectric phases coexistence, increasing bandgap width, strengthening charge compensation and establishing small size of the polar nano-regions (PNRs), which exceeds the great mass of reported lead-free ceramics. The comprehensive properties indicate that the BLLMT0.04 ceramics present potential application in pulse energy storage system. The concept of composition design via increasing bandgap width and strengthening charge compensation provides a new idea for developing lead-free dielectric ceramic capacitors.