Pseudocapacitive Nature Research Articles

Micron-sized H2MoO3/PANI for superfast proton batteries in frozen electrolyte through Grotthuss mechanism

Aqueous proton battery is considered as a promising candidate for the electrochemical energy storage system with the merits of safety, environmental benignity, fast kinetics and low cost. The realization of these advantages relies on the development of suitable and easy-access electrode materials. Herein, micron-sized H2MoO3/Polyaniline (PANI) is developed as a high-rate and stable anode material in proton battery. Contrary to the pseudocapacitive nature of most anode materials, the H2MoO3/PANI presents diffusion-controlled charge storage mechanism with both high capacity and high rate-capability. The H2MoO3/PANI electrode shows a rather high capacity of 268.2 mAh g−1 at 1.0 A g−1, and a surprisingly high rate-capability with ∼50% capacity retention even at an extremely high current density of 200.0 A g−1. Detailed analyses demonstrate the Grotthuss mechanism of ultrafast proton conduction in H2MoO3/PANI. The constructed proton full cell based on H2MoO3/PANI delivers a high energy density of 42.1 Wh kg−1 at 800.0 W kg−1. Impressively, the proton full cell shows fast proton transportation even in the frozen electrolyte, and ∼70% of the room temperature capacity is retained at −20 °C. These excellent proton storage behaviors provide insights into the practical applications of micron-sized electrode materials in proton batteries at low temperatures.

Pseudocapacitive vs diffusion controlled charge storage in Fe2O3 nanosheet Na-ion battery

Despite of its high potential to be the inexpensive-sustainable replacement to lithium, practical deployment of the sodium ion batteries has been practically hindered by the lack of high performance affordable anodes. The practical use of hematite (Fe2O3) electrodes, a high capacity-earth abundant conversion type Na-ion compatible anode, is practically limited by its substantial volumetric fluctuation upon de/sodiation and constraint electronic transport. Herein, we demonstrate highly reliable pseudocapacitive type Fe2O3 nanosheet anodes for Na-ion batteries produced using a simple but largely industrially viable approach. A unique combination of two dimensional morphology and the optimum crystal perturbations collectively impart an exceptional charge transport characteristics and substancial volume fluctuation buffering. Owing to the distinct 2D morphology and structural features, this nanosheet electrode exhibited dominant pseudocapacitive nature with a maximum contribution of 95 % and delivered good reversible specific capacity and cyclability. Mechanistic investigations with the in-situ Raman analysis revealed insignificant structural changes indicating pseudocapacitive nature of the conversion reaction facilitated by the diffusion independent fast Na-ion mobility in the host lattice. The demonstrated method of producing transition metal oxide electrodes with good commercialization potential may be further exploited to achieve the goal for high performance-sustainable batteries.

Enhancing pseudo-capacitive behavior in Mn-doped Co3O4 nanostructures for supercapacitor applications

The study focused on Mn-doped Co3O4 samples, which were synthesized successfully using the coprecipitation method and subsequently annealed at 600 °C. The X-ray diffraction (XRD) patterns displayed distinct peaks corresponding to the spinel-cubic structure of Co3O4. Notably, these patterns indicated a preference for (311) plane orientations, which shifted toward lower diffraction angles as the concentration of Mn increased. The analysis of crystallite sizes for the Mn-doped Co3O4 nanoparticles revealed values of 40 nm, 38 nm, and 38 nm for Co3O4:3%Mn, Co3O4:5%Mn, and Co3O4:7%Mn, respectively. Employing X-ray photoelectron spectroscopy (XPS), the study provided insights into the chemical constituents and valence states of the samples. It revealed the presence of both Co2+ and Co3+ ions, along with different oxygen states. The investigation into the electrochemical behavior of the Mn-doped Co3O4 nanostructures highlighted their pseudo-capacitive nature. The specific capacitance and cyclic stability of these structures were found to be contingent on the concentration of Mn doping. Electrochemical impedance spectroscopy (EIS) data unveiled low interfacial charge resistance and enhanced ion diffusion rates. Notably, the most striking results were observed with the 7 wt% Mn-doped Co3O4 nanomaterials. These materials exhibited an outstanding specific capacitance of 537 F/g at a current density of 1.5 A/g. Additionally, they demonstrated remarkable capacity retention of 94% over a span of 1500 cycles. In conclusion, the Mn-doped Co3O4 nanostructures showcased promising electrochemical performance, which could render them suitable for potential applications in supercapacitors.

Multifunctional electrochromic hybrid PANI@WO3 core-shell for energy generation and storage

Materials that can be deposited easily and shows multifunctional application are always in demand. Two technologically important materials, polyaniline (PANI) and tungsten trioxide (WO3) have been amalgamated using an uncommon, yet simple, technique of deposition, chronoamperometry to obtain a hybrid core-shell structure and its application in three different areas of electrochromic display, electrocatalysis and energy storage has been investigated. Electrodepositing WO3 and PANI onto highly conducting substrates one on top of other, resulted in formation of PANI (shell), WO3 (Core) (PANI@WO3) electrode resulting in a highly uniform fibrous surface structure. Electrochemistry performed using the conventional three electrode step up suggested a very good charge storing capacity, stability also indicating a pseudo capacitive nature which was later confirmed with the help of Nyquist plot. Besides very good values of areal capacitance (855 mF/cm2), power density (6.5 kW/cm2) and energy density (1.09 kWh/cm2) established its supercapacitive performance. Next, its behaviour as an electrocatalyst was studied by duly plotting polarisation curves and their corresponding Tafel plots. The PANI@WO3 electrode deposited on a transparent electrode exhibited green-blue-yellow-transparent color switching under different bias conditions with a very small voltage of 0.5 V. A fast switching of 0.4 s and a great color contrast of ∼50 % in visible as well IR region were displayed making the electrochemically deposited core-shell a good candidate for multifunctional application in energy generation, storage with an inerrability with smart electrochromic windows.

Facile synthesis of flower-like Cu–Zn bimetallic electrodes for high-performance supercapacitors

In this work, a Cu-Zn bimetallic electrode was prepared using a facile electrodeposition technique. Structural and morphological analyses of the electrode samples showed that the explored range has a linear relationship with the composition, consistent with the formation of Cu and Zn in the electrode. The scanning electron microscope images of the fabricated Cu-Zn bimetallic electrode exhibited a cauliflower-like morphology with voids. Cyclic voltammetry studies indicated a clear pseudocapacitive nature of the electrodeposited Cu-Zn electrode material. The Cu-Zn redox electrode deposited for 30 min exhibited the highest specific capacitance of 699 F g−1 at a scan rate of 10 mV s−1. Moreover, the fabricated Cu-Zn electrode demonstrated an excellent capacitance retention of 84 % for 5000 consecutive charge–discharge cycles. The structural stability was also well maintained with an agglomerated spherical morphology filled with several nanorod-type structures. The results elucidate on the mechanisms for electrodeposition and effect of process parameters, such as applied voltage and deposition duration, on enhancing the electrode morphology and electrochemical behavior of Cu-Zn bimetallic electrodes. Our work provides an effective strategy for fabricating high-performance supercapacitor electrodes through a facile method.

Yttria activated lanthanum -barium titanate ceramic electrode for fast charging supercapacitor applications

Lanthanum oxide (La2O3) and Yttria (Y2O3) activated lanthanum-barium-titanate Ba(60-x)Ti(40-y)LaxYyO3 (BTLa10Y10), nanoceramics were investigated for structural, morphological, dielectric and electrochemical properties. These ceramics were prepared through solid-state reaction followed by calcination at 1100 °C for 8 h and sintering temperature at 1275 °C for 6 h. XRD pattern of BTLa10Y10 exposed to a change of crystal structure from rhombohedral (R) to tetragonal (T) after the doping of Y2O3. A feeble FT-IR band at 539 cm−1 was associated to La–O bending vibrations in BTLa10Y10 ceramics. Raman spectral bands at 155 and 214 cm−1 are associated with the R phase, while the modes at 528 and 729 cm−1 are related to the T phase. The clustered particles with a typical grain size of 298 nm, and the pore size of 28.72 (BTLa10) and 27.18 nm (BTLa10Y10) were attained. The Nyquist plot of BTLa10Y10 exhibited two overlapping semicircles at higher frequencies, indicating two relaxation processes. Moreover, the highest specific capacitances and energy densities were reported for BTLa10Y10 due to its pseudocapacitive nature as 3.1106 F/g and 1.5553 W h/Kg, respectively. The electrochemical impedance spectroscopy proved that the linear behaviour of the profile indicates a fast electron response of BTLa10Y10 ceramics are significant for fast charging supercapacitor applications.

MOF-derived porous NiCo2O4 nanofile arrays as an efficient anode material for rechargeable Li-ion batteries

Due to their vast surface area and superior porosity structure, metal-organic frameworks (MOFs) derived materials have recently presented a significant promise for better lithium-ion batteries (LIBs). Herein, we synthesised MOF-derived porous NiCo2O4 nanofile arrays from a simple solvothermal technique followed by calcination at 450 °C. The prepared sample was characterized by X-ray diffraction, thermogravimetric, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Brunauer-Emmett-Teller. The acquired nanofile array morphology achieved a large specific surface area of 189 m2/g can shorten the Li ions (Li+) transport and enhance the electrochemical performance. As expected, the prepared electrode reveals a discharge-specific capacity of around 1120 mAh/g at a 0.1 C rate. At 2 C rate, the electrode's specific capacity can still reach 210 mAh/g after 100 cycles. The pseudocapacitive nature of NiCo2O4 was determined by kinetic analysis, revealing the diffusion-controlled faradaic behaviour. Our prepared electrode material is considered an attractive option for the anode material in rechargeable Li-ion batteries because it has been proven to have a relatively good specific capacity and cycling stability.

Synthesis of Zn doped CrV spinel oxide nanostructures for flexible supercapacitor and hydrogen evolution reaction

Nanostructures containing mixed transition metal oxides with various architectures have been used as promising materials in supercapacitors due to their excellent capacitive contributions. The present work reports on the spinel zinc chromium vanadate ZnCrVO4 (ZCV) nanostructures fabricated via the facile hydrothermal method, for the first time. The pseudocapacitive nature and promising electrocatalytic hydrogen evolution of the prepared ZCV in activated carbon electrodes were confirmed by electrochemical tests. The maximum specific capacitance (Cs) of 448 F g−1 at 1 mA was determined for the ZCV nanostructures s which is far better than pure chromium vanadate (CrV). ZCV containing supercapacitor exhibited the specific energy of 54.5 Wh kg−1 at a power of 1350 W kg−1 and the remarkable coulombic efficiency of the device was recorded at around 99% at 10.000 cycles. In addition, excellent electrochemical hydrogen evolution reaction (HER) kinetics for ZCV were revealed by the Tafel slope (118 mV dec−1) which is quite comparable to the slope of the Pt–C electrode (54 mV dec−1) under the same operating conditions.

Supercapacitor potentiality of tellurium selenide-gadolinium tungsten oxide composite material

In this work, we used a hydrothermal route to synthesize tellurium selenide-gadolinium tungsten oxide material for supercapacitor application. Structural characterization by X-ray diffraction (XRD) revealed that the composite material consists of phases from the starting materials (i.e. Gd2(WO4)3 and Te0.39Se0.61). The composite material was amorphous up to annealing temperature of 700 °C but became crystalline at and beyond 800 °C. Energy dispersive spectroscopy (EDS) results confirmed that all the elements in Gd2(WO4)3 and Se0.61Te0.39 were present except selenium that was not detected in the composite material due to the possibility of overlap between rare earth elements (REE) with selenium. The band gap energy determined for Gd2(WO4)3 is 3.28 eV and after the incorporation of Te0.31Se0.61, it slightly increased to 3.39 eV for Gd2(WO4)3/Te0.39Se0.61. The electrochemical properties of all the materials indicated a quasi-reversible system and the current response was increasing with increasing scan rates indicating battery-type electrodes. The specific capacity obtained from GCD at a current density of 1.2 A g−1 were 64.3, 17.3 and 23.8 C g−1 for Gd2(WO4)3, Te0.39Se0.61 and Gd2(WO4)3/Te0.39Se0.61, respectively. Gd2(WO4)3 showed superior electrochemical performance compared to the composite however, the composite showed more pseudocapacitive nature.

Unravelling the structure and electrochemical performance of Mo–Cu dual-doped NiO nanorod shaped electrodes for supercapacitor application

In this report, the hydrothermal method was adopted to prepare Mo–Cu dual-doped NiO nanorods. A single phase, with the face-centered cubic geometry was confirmed by an x-ray diffraction study in all the nanostructures. A drop in crystallite size with increasing Cu concentrations has a significant impact on the electrochemical performance. Scanning Electron Microscopy (SEM) revealed one-dimensional nanostructure, and the color mapping ascertained the presence of all the incorporated dopants. The confirmation of grown nanorods was ascertained by high-resolution transmission electron microscopy (HRTEM). The electrochemical analysis revealed the pseudocapacitive nature based on the faradaic redox mechanism. A maximum specific capacitance of 1136 F/g was obtained at a 2 mV/s scan rate for Ni1·9Mo0·08Cu0·02O nanorods. The galvanostatic charge-discharge (GCD) analysis carried out at various current densities (1–8 Ag-1), established that the Ni0·9Mo0·02Cu0·08O electrode displays a maximum specific capacitance of 502 F/g at 1 A/g. The Electrochemical Impedance Spectroscopy (EIS) established the perfect capacitive nature in the low-frequency region, with non-uniform distribution of ions. In conclusion, the high specific capacitance (502 F/g) of Ni0·9Mo0·02Cu0·08O electrode at 1 A/g, with energy density (21.10 Wh/kg) and power density (3.44 kW/kg) make it a fascinating candidate for the energy storage devices.

Electrochemical performance of Yttrium doped SnO2–NiO nanocomposite for energy storage applications

Nickel Oxide, Yttrium doped SnO2 and Y:SnO2–NiO nanocomposite were prepared by facile chemical precipitation approach. The XRD investigates the crystallite size, structure and lattice parameters. The morphology of samples and confirm the interplanar spacing of 0.34 nm (1 1 0) for SnO2 and 0.24 nm (1 1 1) for NiO were studied by using HRTEM. The present of elements and oxidation states have been analyzed by FT-IR and XPS. UV–visible spectrum exhibit the red shift in energy band gap and PL spectra show the enhanced intensity of blue emission. VSM exhibit the ferromagnetism at room temperature for Y:SnO2–NiO nanocomposite. Electrochemical behaviors were investigated by EIS at room temperature. The CV curves shows pseudo capacitive nature due to quasi rectangular shape was obtained. The synthesized nanocomposite has good electrochemical performance, optical and magnetic properties and it can be suitable material for energy storage applications.

Performance optimization of Nd-doped LaNiO3 as an electrode material in supercapacitors

Here we present an electrochemically efficient, perovskite series with general formula, La1-xNdxNiO3 (x = 0, 0.05, 0.1, 0.15) for use as electrode material in supercapacitors, prepared using cost effective sol–gel auto-combustion method. X-ray diffraction confirmed the phase development and crystal structure parameters of synthesized samples were determined. Well-defined and uniformly distributed nano-spheres, nano-rods, and nano-size particles were observed using field emission scanning electrode microscopy. The at.% and wt% of the elements in the samples were verified to exist in accordance with their stoichiometric ratios. A detailed electrochemical performance of the novel composite samples was determined using cyclic voltammetry, galvanic charge/discharge, and electrochemical impedance spectroscopy. The electrochemical analysis signified that La0.85Nd0.15NiO3 has surpassed all other composite samples depicting the highest specific capacitance of 64.381 F/g at a lower scan rate of 0.01 Vs−1 through cyclic voltammetry. At the same time, galvanic/discharge, the power density and energy density values came out to be 846.56 W/kg and 20.92 Wh/kg, respectively. This detailed study validates that the composites' pseudo-capacitive nature tends to enlarge their horizon in supercapacitor-based applications.

Nanoscale Engineering of Structurally Stable Nd-Substituted LaCoO3 as An Electrode Material for Supercapacitors

Perovskite oxides have recently emerged as a novel class of electrochemical materials owing to their amazing reversible redox capabilities and enriched electrical characteristics, rich oxygen vacancies, and highly stable structure. Herein, the impact of Nd-substitution on the morphological and electrochemical features of Nd-doped LaCoO3 nanoparticles has been studied. A facile and cost-effective sol-gel process routed via auto-ignition was used for sample synthesis. The development of pure single-phase cubic LaCoO3 perovskite and its structural stability throughout the series was confirmed via X-ray diffraction. The transformation from sponge-like structure to grains-like morphology was evident by a field-emission scanning electron microscope. Cyclic voltammetry measurements revealed a surface redox and intercalation pseudo-capacitive nature of the samples. It is outcome that La0.95Nd0.05CoO3 at 6 A g−1 of current density exhibits paramount power (5788.8 W kg−1) and energy (0.975 Wh kg−1) densities. All the revealed consequences had inferred La0.95Nd0.05CoO3 (x = 0.05) as a potential candidate for electrode material in supercapacitors.

Morphology tuned electrochemical properties of CuBO2 nanostructures

Various CuBO2 nanostructures were developed using different synthesis methods like sol-gel, hydrothermal and molten salt route. The synthesis procedures include different starting materials as well as different sets of synthesis parameters. The resulting samples showed different shapes like nanoparticles, nanocubes and nanorods and exhibited different stoichiometric, crystallographic and electrical properties. The samples were thoroughly characterized by XRD diffractometer, FESEM, EDX, electrometer for structural, morphological, stoichiometric and electrical properties. The sample synthesized via sol-gel method exhibited highest aspect ratio. All samples were subjected to thorough electrochemical studies which showed that the copper boron oxide (CBO)nanoparticles synthesized via sol-gel route can act as the most efficient candidate (specific capacitance142μF) for supercapacitor applications compared to the other nanostructures of CBO. Another interesting feature involving the type of electrochemical properties was found in this work. The NP sample obtained via sol-gel method showed pseudo capacitive nature whereas it gradually expressed EDLC as the samples exhibited different nanostructures of cubes and rods. The electrochemical properties were correlated with the aspect ratio, surface area and the constituent elemental variation of the samples. This work has introduced an entirely new era of applications of CBO in addition to its green cleaning application cooled electron application and photo response efficiency.

Synergistic effect in g-C3N4/CuO nanohybrid structures as efficient electrode material for supercapacitor applications

A facile thermal decomposition and hydrothermal techniques were used to fabricate g-C3N4/CuO nanohybrid electrode material. The pure g-C3N4, CuO and g-C3N4/CuO nanohybrid composites were confirmed by powder X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and Fourier-transform infrared spectroscopy (FTIR). The g-C3N4/CuO electrode material exhibited a specific capacitance of 98F/g which is substantially higher than those using bare CuO (40F/g) and bare g-C3N4 electrodes (62F/g). Cycle-life data for over 2500 cycles reflect 19 % capacitance degradation for g-C3N4/CuO nanohybrid material. The energy density given by g-C3N4/CuO, CuO and g-C3N4 devices is 14.8 W h kg−1, 5 W h kg−1 and 6.3 W h kg−1 respectively. The enhanced electrochemical performance of the nanohybrid material is ascribed to synergistic effect and pseudo capacitive nature of the metal oxide nanoparticles incorporated in the g-C3N4 matrix.

Biogenic Synthesis of High-Performance α-MoO3 Nanoparticles from Tryptophan Derivatives for Antimicrobial Agents and Electrode Materials of Supercapacitors

Molybdenum trioxide nanoparticles (MoO3 NPs) are recognized for their applications in novel multifunctional devices. Here, a biogenic, environmentally friendly method using Lepidagathis cristata leaf extract was employed to synthesize MoO3 NPs. The as-obtained MoO3 NPs exhibited a predominant (0 k0) orientation, representing an α-MoO3 structure. The absorption band at 984 cm-1 observed in the Fourier-transform infrared spectrum corresponded to the terminal Mo = O bond, thereby confirming that the prepared MoO3 NPs were in the orthorhombic phase. Scanning and transmission electron microscopy data revealed that the MoO3 NPs were well crystallized and uniformly distributed with grain sizes in the 70-100 nm range. The biogenic MoO3 NPs demonstrated an excellent zone of inhibition against the selected Gram -ve and Gram +ve bacterial strains, thus providing an alternative to standard antibacterial agents. During electrochemical experiments conducted in a 1 M aqueous Na2SO4 solution, cyclic voltammetry (CV) curves of the MoO3 NPs showed a pseudocapacitive nature, with a high discharge specific capacitance of 294 F/g and good cyclability. These results suggest the feasibility of the proposed biogenic, environmentally friendly method for preparing MoO3 NPs for application in multifunctional devices.

Green-engineered synthesis of Bi2Zr2O7 NPs: excellent performance on electrochemical sensor and sunlight-driven photocatalytic studies.

In this rapid growing eco-friendly research world, synthesis of non-toxic, highly effective photocatalyst for potential applications is necessary. Herein, a strong ability Bi2Zr2O7 nanoparticle (BZO NP) with pyrochlore structure was fabricated by solution combustion synthesis using green (Mentha spicata) and chemical (Glycine) fuels. The X-ray diffraction analysis confirms the formation of pure phase for synthesized BZO NP using pudina extract (BZOP NP) compared to BZO NP using Glycine fuel (BZOG NP). The lower energy band gap of synthesized BZOP NP was observed than BZOG NP and its values were found to be 2.26 and 2.49eV measured by UV-visible absorbance spectral technique. The morphological analysis of pores and voids formation as examined by scanning electron microscopy (SEM) technique. The synthesized BZOP NP shows excellent photocatalytic activity for degradation of three different dyes under sunlight irradiation for about 150min with 97.9% for Rose Bengal (RB) dye with lower charge transfer resistance (Rct) value. For the very first time, the synthesized NPs can be utilized as supercapacitor with good specific capacitance (SPCcv) value of 14.3 F/g and SPCGD (12.5 F/g) for BZOP compared to BZOG indicating pseudocapacitance nature. The synthesized nanoparticles (NPs) can sense lead nitrate and dextrose at concentration 1-5mM in the potential range of - 1.0 to + 1.0V. Accordingly, the reduction potential peak at - 0.25V and oxidation potential peak found at - 0.82V confirms the presence of lead content and presence of additional potential peaks at - 0.37V and - 0.71V for detection of dextrose biochemical. Recyclability experiment showed the retainment of photocatalytic activity up to five cycles indicating the photostability.

Porous 3D columnar-sphere of NiO nanomaterials synthesized for supercapacitors via hydrothermal route: impact of thiourea concentration.

The charge storage application has witnessed a dramatic increase in terms of the short charge-discharge time of supercapacitors, specifically in highly active electrode materials. For charge storage supercapacitor applications, highly porous materials are preferable. In this research article, thiourea acts as a leaving agent in the preparation of the porous 3D spherical architecture of NiO nanomaterials. The influence of the molar concentration of thiourea on structural, morphological, and electrochemical charge storage applications has been studied. X-ray diffraction reveals a cubic structure with Fm3̄m space group for the NiO nanomaterials. The scanning electron microscopy (SEM) images show the porous 3D columnar spherical structure, and FTIR has been used for the optical analysis of the NiO materials. The 1D-3D columnar-spherical structure of the NiO flakes exhibits a high electrochemical charge storage pseudocapacitive nature. The optimized 0.40 M thiourea-NiO (Th-NiO) nanomaterial is highly hydrophilic, exhibiting a maximum specific capacity of 171.1 mA h g-1 at 5 mV s-1 by CV and 148.5 mA h g-1 at 0.2 mA cm-2 by GCD. The highest power, energy densities are 0.96 kW kg-1 and 6.66 W h kg-1 with the highest charge-discharge cycle rating of 92% up to 5000 cycles of the asymmetric NiO//rGO hybrid supercapacitor device.

Band gap and pseudocapacitance of Gd2O3 doped with Ni0.5Zn0.5Fe2O4

Herein, we present a detailed study of the structural, optical, and electrochemical responses of Gd2O3 doped with nickel zinc ferrite nanoparticles. Doping of Ni0.5Zn0.5Fe2O4 nanoparticles to Gd2O3 powder was done through thermal decomposition at 1000 °C. The average grain size of the mixture was determined to be approximately 95 nm, and phases of cubic Gd2O3, GdO, and orthorhombic prisms of GdFeO3 were identified. The focused ion beam energy dispersive x-ray spectrum (FIB-EDX) mapping results clearly show the morphology of the particles with Gd and Fe as the dominant elements. The structural data were compared with the spectroscopic measurements confirming the formation of multiple phases of oxides and ferrites. The measured optical band gap is significantly redshifted to 1.8 eV and is close to that of nitride compounds of gadolinium metal. The measured specific capacitance was almost 7 Fg−1 at a current density of 1 Ag−1, showing a small drop of 27% when the current density is increased to 10 Ag−1. Cyclic voltammetry (CV) plots of the ferrite doped Gd2O3 electrode at a scan rate of 5 to 100 mV s−1 indicate the pseudocapacitive nature of the material.

Enhanced Pseudocapacitance of the LaNiO3 Perovskite in p‐Phenylenediamine as Redox‐Active Electrolyte

AbstractPerovskite oxides are well known for their excellent properties such as catalytic activity, oxygen ion mobility and structure stability. These properties make it a most suitable material for energy storage devices like fuel cells, batteries and supercapacitors. In the present work, LaNiO3 perovskite was synthesized using the sol‐gel method and its morphological parameters were characterized by XRD, SEM and FTIR. The anion‐intercalated pseudocapacitive nature of LaNiO3 powder was studied in 2M KOH as well as in the mixture of 2M KOH with p‐phenylenediamine (PPD) as an alkaline aqueous and redox‐active electrolyte respectively. Electrochemical performance characteristics cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopy (EIS) of LaNiO3 has shown pseudocapacities of 300.60 Fg−1 at a scan rate of 5 mV s−1 and 440 F g−1 at a current density of 1 A g−1 in KOH+PPD electrolyte. Furthermore, a symmetrical pseudocapacitor has been fabricated using LaNiO3 as electrode active material with 2M KOH+PPD as an redox‐active electrolyte. The device delivered an energy density of 13.75 Wh kg−1 at the power density of 500 W kg−1 at a potential of 1 V. This excellent performance may be due to the synergic effect of both redox active electrode (LaNiO3) and electrolyte (KOH+PPD) that together demonstrated a great combination for high performance pseudocapacitors for future applications.