Impact of Sr Content on the Morphology and Electrochemical Properties of La1−xSrxMnO3 Perovskites for High-Performance Supercapacitors

Electroconversion synthesis of Ni/Co layered nanomaterials for high-performance supercapacitors

Acid-treated waste sisal fiber derived activated carbon as efficient electrode material for solid-state supercapacitor

Low-dimensional hybrid lead-halide perovskites with broadband white-light emission upon near-UV excitation have attracted immense scientific interest due to their potential application for the next...

Machine Learning for Perovskites' Reap-Rest-Recovery Cycle

This paper reports the studies on the effect of A-site substitution by strontium on the structural properties and magnetic ordering in polycrystalline perovskite Sm0.5Ca0.5−xSrxMnO3 (x = 0.1, 0.2 and 0.3). The investigated samples are prepared by conventional solid-state reaction technique. XRD analysis at room temperature has confirmed orthorhombic structure of the sample with space group Pnma. The dependence of structural parameter, Curie temperature and coercivity on Sr doping content has been thoroughly investigated. It is observed that substitution of Sr2+ for Ca2+ increases lattice parameter, tolerance factor and the Curie temperature. However, the coercivity (Hc) decreases with increasing Sr content while the charge ordering process is weakened with increasing Sr content. Field cooled (FC) and zero-field cooled (ZFC) dc magnetizations measurements at low field and low temperature indicate that there is a spin-glass (SG) like state occurred. Temperature dependent ac susceptibility at different frequency indicates a spin-glass-like transition of the sample.

Biomass-based controllable morphology of carbon microspheres with multi-layer hollow structure for superior performance in supercapacitors

Preparation of electrospun Co3O4 nanofibers as electrode material for high performance asymmetric supercapacitors

In this work, novel phosphate materials based on bimetallic character (Fe and Ni) were introduced by different chemical fabrication methods, the reflux method (FeNiP-R) and the sol–gel technique (FeNiP-S), and evaluated as non-precious electrodes for methanol electrooxidation in KOH electrolytes. The designed FeNiP-R and FeNiP-S samples were investigated using different characterization techniques, namely TEM, SEM, XPS, BET, DLS, and FT-IR, to describe the impact of the fabrication technique on the chemistry, morphology, and surface area. The characterization techniques indicate the successful fabrication of nanoscale-sized particles with higher agglomeration by the sol–gel technique compared with the reflux strategy. After that, the electrochemical efficiency of the fabricated FeNiP-R and FeNiP-S as electrodes for electrocatalytic methanol oxidation was studied through cyclic voltammetry (CV) at different methanol concentrations and scan rates in addition to impedance analysis and chronoamperometric techniques. From electrochemical analyses, a sharp improvement in the obtained current values was observed in both electrodes, FeNiP-R and FeNiP-S. During the MeOH electrooxidation over FeNiP-S, the current value was improved from 0.14 mA/cm2 at 0.402 V to 2.67 mA/cm2 at 0.619 V, which is around 109 times the current density value (0.0243 mA/cm2 at 0.62 V) found in the absence of MeOH. The designed FeNiP-R electrode showed an improved electrocatalytic character compared with FeNiP-S at different methanol concentrations up to 80 mmol/L. The enhancement of the anodic current density and charge transfer resistance indicates the methanol electrooxidation over the designed bimetallic Fe/Ni-phosphates.

Halide Perovskites – Optoelectronic and Structural Characterization Methods

Hierarchical structured Sm2O3 modified CuO nanoflowers as electrode materials for high performance supercapacitors

Engineering large active surface area, fast ion transfer, and wide work voltage are indispensable for using porous carbon as an electrode material for high energy density and high rate capability supercapacitors. Here, a method is proposed to fabricate N/O/P/S heteroatom co-doped hierarchical porous carbon materials via zinc carbonate hydroxide ([ZnCO3]2∙[Zn(OH)2]3) assisted activation of the biomass-based ternary complex. By adjusting the pH of the ternary complex and the mass ratio of [ZnCO3]2∙[Zn(OH)2]3, it is demonstrated that TCPC-7-0.5 with high specific surface area (1360 m2 g−1), appropriate micropore surface area (672 m2 g−1), and micropore volume (0.3 cm3 g−1) possesses excellent electrochemical performance. The unique pore structure accelerates the transport of electrolyte ions and provides more effective active sites for their adsorption. As a result, as an electrode material for supercapacitors, it maintains excellent frequency response at a larger scan rate of 1 V s−1. The working voltage range of the assembled symmetrical supercapacitor TCPC-7-0.5//TCPC-7-0.5 in 6 M KOH electrolyte can be effectively expanded to 1.2 V. Most importantly, it can simultaneously achieve an energy density of 7.01 W h kg−1 at a high-power density of 15 kW kg−1.

This research presents a simple method for preparing poly Schiff base ligand (L) and its metal complex (M–L, M = Al3+, Cr3+, Zn2+) as electrode materials for supercapacitors, which is derived from mixing terephthalaldehyde, m-phenylenediamine and metal nitrate in ethanol at room temperature. Compared with L, M–L combine the advantages of larger surface area, appropriate mesopore diameter, unique morphology and suitable conductivity. The electrochemical properties of the materials are assessed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) analysis in 6 M KOH electrolyte. The results show that the electrochemical performance of M–L significantly improve compared with L, especially when the current density is 0.5 A g−1, Al–L displays a superior specific capacitance of 608.6 F g−1. Moreover, the specific capacitance of Al–L still reaches 299.1 F g−1 after 1000 GCD cycles at 10 A g−1, which is higher than the initial capacitance of Cr–L and Zn–L. Moreover, the electrochemical resistance of Al–L is smaller than that of others. Therefore, Al–L will become an attractive material in supercapacitors, and opens the door for further research on various poly Schiff base metal complexes (poly[M(Schiff)]) as electrode materials for supercapacitors.

High-surface area-activated carbons (ACs) are successfully prepared by coal-tar pitch (CTP)/sawdust (SD) co-carbonization followed by simple KOH activation. The ACs inherit the tubular morphology of the biomass and possess a hierarchical porous structure, a high specific surface area of 2224 m2/g, and a considerable amount of oxygen-containing species on the surface. The AC obtained from the co-carbonization of 67 % CTP and 33 % SD has a 25 wt% higher oxygen content than the AC (0.17 wt%) from 100 % CTP, and has a 27.50 wt% higher carbon yield than the AC (14.42 wt%) from SD. As an electrode material for supercapacitors, the prepared electrode from 67 % CTP and 33 % SD exhibits a favorable specific capacitance of 251 F/g at a current density of 0.5 A/g in 6 mol/L KOH electrolyte. The electrode also demonstrates excellent cycling stability with a retention rate of 93 % over 7000 cycles at 2 A/g and a favorable rate capability with a retention rate of 74 % when the current density increases from 0.5 to 5 A/g. Therefore, the ACs obtained by co-carbonizing CTP and SD have high potential as electrode materials. This route not only enhances the benefit from agricultural wastes, but also reduces the cost of producing electrode materials for supercapacitors.

Dinuclear cobalt-based pillar-layered-like MOF as an electrode material for supercapacitor and photocatalysis activity

Hierarchical NiCo2O4 nanowalls composed of ultrathin nanosheets as electrode materials for supercapacitor and Li ion battery applications