Effects of Calcium Substitution for La on the Electrochemical Performance of LaMnO₃ Nanoparticles

Abstract

With the advantages of short charging and discharging times, high power density, and long cycle life, supercapacitors are regarded as one of the most promising energy storage devices and have garnered massive attention in the field of energy storage. This paper prepared La1−xCaxMnO3 (x=0, 0.05, 0.1, 0.15, and 0.2) nanoparticles by the sol‐gel method. The microstructure, morphology, and electrochemical performance of the samples were characterized. The results depict that La0.85Ca0.15MnO3 has a low charge transfer resistance (0.19 Ω) and a large specific surface area (38.79 m2 g−1). The maximum specific capacitance of the La0.85Ca0.15MnO3 sample reached 248 F/g at a current density of 0.5 A/g, which is ascribable to its large specific surface area and high oxygen vacancy concentration. The anion‐intercalation mechanism was investigated by the charging and discharging process. The above results depict that Ca‐doping significantly enhances the electrochemical performance of LaMnO3 system.

Enhanced Electrochemical Performance of LaMnO3 Nanoparticles by Ca/Sr Doping

“…Doping causes a reduction in the average ionic radius at point A due to the larger ionic radius of La 3+ (1.06 Å) compared to Ca 2+ (0.99 Å). The presence of alternating long and short A-site cation radii can lead to a significant mismatch in the MnO 6 octahedra and a pronounced bending of the Mn-O-Mn bond angles [21,22,29]. This mismatch exerts a considerable influence on the orthorhombic structure, causing elongation along the c-axis due to the Jahn-Teller effect and amplifying the lattice distortion of the compounds [21,22,29].…”

“…The presence of alternating long and short A-site cation radii can lead to a significant mismatch in the MnO 6 octahedra and a pronounced bending of the Mn-O-Mn bond angles [21,22,29]. This mismatch exerts a considerable influence on the orthorhombic structure, causing elongation along the c-axis due to the Jahn-Teller effect and amplifying the lattice distortion of the compounds [21,22,29]. It is clear that replacing La 3+ with a smaller Ca 2+ reduces the lattice volume and thus increases the diffraction angle.…”

“…Pseudocapacitance relies on oxygen vacancies within perovskite as locations for storing charges [18]. The oxygen vacancies can be determined using neutron powder diffraction and X-ray photoelectron spectrometry [19][20][21][22]. According to the findings, it is primarily the pseudocapacitance resulting from the intercalation of oxygen anion that contributes significantly to the high specific capacitance of perovskite materials [1].…”

Electrochemical Properties of LaMO3(M=Cr, Mn, and Co) Perovskite Materials

“…Tyler Mefford et al proposed an oxygen-embedding mechanism to provide a theoretical basis for the energy storage of perovskite materials [17]. Subsequently, the researchers reported some perovskite oxide materials as electrode materials for supercapacitors, such as strontium-based materials [18][19][20], nickel-based materials [21,22], ceriumbased materials [23][24][25], and lanthanum-based materials [26][27][28][29][30]. Lanthanide perovskite oxides have attracted significant attention because they have a stable crystal structure, high thermal stability, fantastic electrical conductivity, low cost, and excellent thermal stability.…”