BaTiO3-(Bi0.5Na0.5)TiO3 (BTBNT)-based multilayer ceramic capacitor (MLCC) chips with the inner electrodes being Ag0.6/Pd0.4 are prepared by a roll-to-roll casting method. The BTBNT-based MLCC chips with ten-dielectric layers can be sintered very well at a low temperature of 1130 degrees C via two-step sintering (TSS). X-ray diffraction (XRD) and transmission electron microscope (TEM) results show that MLCC chips are a core-shell structure with two phases coexistence. The core exhibits a tetragonal phase at room temperature and then gradually changes into a cubic phase when the temperature increases above T-c (175 degrees C). While, the shell exhibits a pseudocubic phase at all tested temperature from 25 degrees C to 500 degrees C. BTBNT-based MLCC chips exhibit a broad temperature stability and meet the requirement of Electronic Industries Association (EIA) X9R specifications. In terms of energy storage performance, a large discharge energy density of 3.33J/cm(3) can be obtained at 175 degrees C under the applied electric field of 480kV/cm. Among all tested temperature ranging from -50 degrees C to 200 degrees C, the energy efficiency of all chips is higher than 80%, even under a high applied electric field. The experimental results indicate that this novel BTBNT-based X9R MLCCs can be one of the most promising candidates for energy storage applications, especially operated in high temperature.