Structures and dielectric properties of La 1.5 Sr 0.5 NiO 4 ceramics with different contents of SiO 2 additives were investigated. The La 1.5 Sr 0.5 NiO 4 particles were dispersed into SiO 2 matrixes via a sol-gel process, while the homogeneous distribution was destroyed by the reaction between La 1.5 Sr 0.5 NiO 4 and SiO 2 during the sintering process, so the composite ceramics consisted of La 1.5 Sr 0.5 NiO 4 , La 9.33 Si 6 O 26 and NiO phases. The dielectric constants at room temperature varied slightly, while the dielectric losses could be suppressed with a moderate amount of SiO 2 additive. Temperature-independent giant dielectric constant with low loss was achieved in the ceramics with nominal composition of La 1.5 Sr 0.5 NiO 4 -0.80SiO 2 . Based on the analysis of impedance spectra, the giant dielectric response in the composite ceramics was attributed to the combination of the small polaronic hopping and Maxwell-Wagner effect.

The combustion process of GOA, and the specific surface area and pore size distribution of P-RGO are shown in the images.