Electrochemical Material Processing via Continuous Charge‐Discharge Cycling: Enhanced Performance upon Cycling for Porous LaMnO₃ Perovskite Supercapacitor Electrodes

Abstract

Creating controlled porous morphologies in smart materials offers a significant enhancement in their properties, which can not only open access to various applications, but also improve their efficiency and performance. Among smart materials, porous carbon electrodes have been receiving much attention owing to their smooth and faster ionic kinetics in regard to their electrode‐electrolyte interface, which is promising for the development of high performance devices with a prolonged lifetime. Various techniques including soft and hard templating approaches are available for controlling the pore structure and morphological control of these porous carbon nanostructures, used as negative electrodes. However, reports on stable porous positive electrodes are quite limited. Here, we report on porous LaMnO3 electrodes and their application in symmetric supercapacitors exhibiting high energy and power densities over prolonged lifetime (>110,000 cycles). We demonstrate that a simple electrochemical cycling process can be used as an efficient tool to create proper channels by interconnecting the adjacent pores of the porous electrode material to facilitate smooth and faster ionic transport or intercalation/deintercalation of electrolyte species into the electrode surface. The creation of channels and preconditioning of the electrode surface are well investigated by analysing the voltammogram at various cycles and supports the enhancement of the supercapacitance even after myriad cycles.

Sr- and Fe-substituted LaMnO3 Perovskite: Fundamental insight and possible use in asymmetric hybrid supercapacitor

“…Furthermore, the 0D exohedral structure, small diameter, high electrical conductivity, and relatively easy aqueous media dispersion, compared to the extensively used 1D nanotubes and 2D graphene, could potentially enhance the electrochemical rate-performance of other oxides/sulfide-based perovskite electrode materials. This excellent consistency is comparable to previously reported high-energy supercapacitor devices and even better than substituted and unsubstituted LMO perovskitebased devices [20,21,[37][38][39][40][41].…”

“…The bare and substituted perovskite materials, such as LaMnO 3 , Sr-substituted LaMnO 3 (LaSrMnO 3 ), and Fe-substituted LaSrMnO 3 (La 0.7 Sr 0.3 Mn (1-x) Fe x O 3 ), were prepared using a previously developed synthesis method [19,20]. Lanthanum nitrate (La(NO 3 ) 3 • 6H 2 O, 99.999%, Sigma-Aldrich), strontium nitrate (Sr(NO 3 ) 2 , 99.995%, Sigma-Aldrich), manganese sulfate (MnSO 4 • H 2 O, >99%, Sigma-Aldrich), and iron nitrate (Fe(NO 3 ) 3 • 9H 2 O, > 99.95%, Sigma-Aldrich) were used as the precursor materials.…”

Spray-Flame Synthesis of LaMnO3+δ Nanoparticles for Selective CO Oxidation (SELOX)

“…Lanthanum-containing manganites (LaMnO 3 ) are perovskite-type oxides that have been studied over the years for their diverse and interesting magnetic and electrochemical properties, e.g., colossal magnetoresistance in doped manganites , and high-energy storage and power densities in Li-ion batteries. , Recently, these compounds also attracted growing attention for their versatile catalytic properties combined with chemical stability, especially regarding their potential as low-cost substitutes of noble-metal catalysts for environmentally relevant reactions as CO oxidation and CO selective oxidation (SELOX). − They can be applied for, e.g., removing CO from enclosures and residue gases to avoid the poisoning of catalysts in proton-exchange membrane fuel cells for H 2 production. , …”

“…The formation of a specific polymorph depends on the selected synthesis technique . To produce rhombohedral/orthorhombic-LaMnO 3+δ nanoparticles, typically batch processes such as sol–gel or the citrate method are used. These processes count with a final calcination step involving temperatures usually higher than 600 °C , and long annealing periods of >2 h, making the formation of crystalline manganites with high surface area and thus low-size particles (ideally <20 nm) a challenge.…”

Symmetric/asymmetric energy storage device of reduced graphene oxide assisted LaNi0.9Co0.1O3 perovskite nanomaterials

“…The mechanism involved during electrochemical reaction is shown in Scheme 1. The pseudocapacitance cum anion intercalation mechanism is well followed by perovskite materials, i.e., LaMO 3 (M = Ni, Mn, Co, Fe, Cu), which are responsible for higher specific capacitance [14][15][16][17][18]. Also, the reported results for specific capacitance, longer life cycle and higher stability of doped perovskite oxides, i.e., LaNiO 3-ϐ , La x Sr 1-x NiO 3-ϐ , La 0.7 Sr 0.3 CoO 3-δ , etc., encourage the researchers to fabricate the working electrodes.…”