Supercapacitors are attractive as a major energy storage device due to their high coulombic efficiency and semi-permanent life cycle. Transition metal oxides are used as electrode material in supercapacitors due to their high conductivity, capacitance, and multiple oxidation states. Nanopowder transition metal oxides exhibit low specific surface area, ion diffusion, electrical conductivity, and structural stability compared with the three-dimensional (3D) structure. Furthermore, unstable performance during long-term testing can occur via structural transition. Therefore, it is necessary to synthesize a transition metal oxide with a high specific surface area and a stable structure for supercapacitor application. Transition metal oxides with a perovskite structure control structural transition and improve conductivity. In this study, a NiMnO₃ perovskite oxide with a high specific surface area and electrochemical properties was obtained via hydrothermal synthesis at low temperature. Hydrothermal synthesis was used to fabricate materials with an aqueous solution under high temperature and pressure. The shape and composition were regulated by controlling the hydrothermal synthesis reaction temperature and time. The synthesis of NiMnO₃ was controlled by the reaction time to alter the specific surface area and morphology. The prepared perovskite NiMnO₃ oxide with a three-dimensional structure can be used as an active electrode material for supercapacitors and electrochemical catalysts. The prepared NiMnO₃ perovskite oxide showed a high specific capacitance of 99.03 F·g⁻¹ and excellent cycle stability with a coulombic efficiency of 77% even after 7000 cycles.

Layered perovskite oxides are considered as promising cathode materials for the solid oxide fuel cell (SOFC) due to their high electronic/ionic conductivity and fast oxygen kinetics at low temperature. Many researchers have focused on further improving the electrochemical performance of the layered perovskite material by doping various metal ions into the B-site. Herein, we report that Sc³⁺ doping into the layered perovskite material, PrBaCo₂O_5+δ (PBCO), shows a positive effect of increasing electrochemical performances. We confirmed that Sc³⁺ doping could provide a favorable crystalline structure of layered perovskite for oxygen ion transfer in the lattice with improved Goldschmidt tolerance factor and specific free volume. Consequently, the Sc³⁺ doped PBCO exhibits a maximum power density of 0.73 W cm⁻² at 500 °C, 1.3 times higher than that of PBCO. These results indicate that Sc³⁺ doping could effectively improve the electrochemical properties of the layered perovskite material, PBCO.

In this study, sulfur tolerance of a conventional Ni-yttria stabilized zirconia (Ni-YSZ) anode for solid oxide fuel cells is significantly improved by surface modification. The Ni-YSZ anode modified by the infiltration of BaZr_0.1Ce_0.7Y_0.1Yb_0.1O_3−δ (BZCYYb) demonstrates stable performance in a sulfur-containing H₂ fuel over 500 hours. In contrast, the bare Ni-YSZ anode without surface modification degrades drastically when exposed to the sulfur-containing H₂ fuel. This implies that the BZCYYb coating is an excellent catalyst for surface modification of the conventional Ni-YSZ anode. A single step infiltration of BZCYYb into the Ni-YSZ anode was sufficient to provide good sulfur tolerance.

Supercapacitors are promising energy storage devices with high charging/discharging speeds and power densities. To improve their poor stability, we fabricated electrodes by integrating perovskite materials (La_0.8Sr_0.2Mn_0.5Co_0.5O_3-δ, LSMCO) possessing redox reaction ability with graphene nanoplatelets exhibiting good electronic properties. One of the resultant composites (L25G70) demonstrated high capacitance and excellent capacitance retention (95% after 5000 cycles). These results are superior to other electrodes (L50G45 and L75G20) containing a larger ratio of LSMCO, even L75G20 did not exhibit supercapacitor behavior after 3000 cycles. GN can induce structural distortion in LSMCO, thereby the high amount of adsorbed oxygen per lattice oxygen can explain the best electrochemical performance of L25G70, while structural collapse rationalized the failure of L75G20. The findings of this study demonstrated that the use of LSMCO can improve the cycling stability of supercapacitors.