A simple but efficient Li-doping approach for enhancing supercapacitor performance of the BiFeO3 perovskite nanostructures

The capacitive energy storage mechanism offers quick charging, an extended life span, and, far, higher power density compared to batteries. This study presents a simple and efficient lithium (Li)-doping approach for enhancing electrochemical energy storage properties of perovskite-type bismuth ferrite (BiFeO3) i.e. Bi1-xLixFeO3 (BLFs), where x = 0, 0.05, 0.10, 0.15, and 0.20. An addition of the Li results in a significant decrease in the crystallite size of the BiFeO3 from 67 nm to 26 nm, and, in addition to the surface morphology, the Bi/Fe ratio is changed. Electrochemical tests, performed in 6.0 M KOH electrolyte solutions in a half-cell system, have confirmed a significant increase in the specific capacitance (SC) and specific capacity values. After Li-doping, at a current density of 5 A g-1, the SC of the pristine BLF electrode increases to 807.5 from 175.5 F g-1 (specific capacity (Q) = 21.4-100.94 mA h g-1) for the x = 0.10 Li-doped BLF electrode. The as-manufactured BLF-C//Bi2S3 asymmetric supercapacitor device, wherein Bi2S3 acts as a negative electrode and BLF-C as a positive electrode, in addition to an energy density of 48.65 W h kg-1 and a power density of 750 W kg-1, delivers an outstanding 155.6 F g-1 SC (Q = 64.8 mA h g-1) at a current density of 5 A g-1. The 'CNED' screen, consisting of nearly 42 bright LEDs, is ignited at full brightness by connecting a twin-cell (BLF-C//Bi2S3) assembly. Even after 5000 redox cycles, the as-designed BLF-C//Bi2S3 asymmetric supercapacitor demonstrates an exceptional 92.67% cycling stability, suggesting the importance of an adopted Li-doping strategy for obtaining an enhanced energy storage performance in energy storage devices.

Impact of Nitrogen-Enriched 1T/2H-MoS2/CdS as an Electrode Material for Hybrid Supercapacitor

Transition metal chalcogenides (TMX) have attracted energy researchers due to their role as high-performance electrode materials for energy storage devices. A facile one-pot hydrothermal technique was adopted to synthesize a molybdenum disulfide/cadmium sulfide (MoS2/CdS) (MCS) composite. The as-prepared samples were subjected to characterization techniques such as XRD, FT-IR, SEM, TEM, and XPS to assess their structure, morphology, and oxidation states. The MoS2/CdS (MCS) composites were prepared in three different ratios of molybdenum and cadmium metals. Among them, the MCS 1:2 (Mo:Cd) ratio showed better electrochemical performance with a high specific capacitance of 1336 F g-1 (high specific capacity of 185.83 mAh g-1) at a specific current of 1 A g-1 for half-cell studies. Later, a hybrid supercapacitor (HSC) device was fabricated with N-doped graphene (NG) as an anode and MCS (1:2) as a cathode, delivering a high specific energy of 34 Wh kg-1 and a specific power of 7500 W kg-1. The high nitrogen content in the MoS2 structure in MCS composites alters the device's performance, where CdS supports the composite structure through its conductivity and encourages the easy accessibility of ions. The device withstands up to 10 000 cycles with a higher Coulombic efficiency of 97% and a capacitance retention of 90.25%. The high-performance NG//MCS (1:2) HSC may be a potential candidate alternative to the existing conventional material.

Exploring morphological variation in bismuth ferrite nanostructures by pulsed laser deposition: synthesis, structural and electrochemical properties

Structural and electrochemical properties of bismuth ferrite nanostructures produced by pulsed laser deposition with various morphologies are reported. The nanostructures are also explored as electrode materials for high-performance supercapacitors. Scanning electron microscopy images revealed that various bismuth ferrite morphologies were produced by varying the background pressure (10-6, 0.01, 0.10, 0.25, 0.50, 1.0, 2.0 and 4.0 Torr) in the deposition chamber and submitting them to a thermal treatment after deposition at 500◦C. The as-deposited bismuth ferrite nanostructures range from very compact thin-film (10-6, 0.01, 0.10 Torr), to clustered nanoparticles (0.25, 0.50, 1.0 Torr), to very dispersed arrangement of nanoparticles (2.0 and 4.0 Torr). The electrochemical characteristic of the electrodes was investigated through cyclic voltammetry process. The increase in the specific surface area of the nanostructures as background pressure in the chamber increases does not lead to an increase in interfacial capacitance. This is likely due to the wakening of electrical contact between nanoparticles with increasing porosity of the nanostructures. The thermal treatment increased the contact between nanoparticles, which caused an increase in the interfacial capacitance of the nanostructure deposited under high background pressure in the chamber.

Effect of metal doping (Me = Zn, Cu, Co, Mn) on the performance of bismuth ferrite as peroxymonosulfate activator for ciprofloxacin removal

In this study, a facile hydrothermal method was employed to prepare Me-doped Bi₂Fe₄O₉ (Me = Zn, Cu, Co, and Mn) as peroxymonosulfate (PMS) activator for ciprofloxacin (CIP) degradation. The characteristics of the Me-doped bismuth ferrites were investigated using various characterization instruments including SEM, TEM, FTIR and porosimeter indicating that the Me-doped Bi₂Fe₄O₉ with nanosheet-like square orthorhombic structure was successfully obtained. The catalytic activity of various Me-doped Bi₂Fe₄O₉ was compared and the results indicated that the Cu-doped Bi₂Fe₄O₉ at 0.08 wt.% (denoted as BFCuO-0.08) possessed the greatest catalytic activity (k_app = 0.085 min^-1) over other Me-doped Bi₂Fe₄O₉ under the same condition. The synergistic interaction between Cu, Fe and oxygen vacancies are the key factors which enhanced the performance of Me-doped Bi₂Fe₄O₉. The effects of catalyst loading, PMS dosage, and pH on CIP degradation were also investigated indicating that the performance increased with increasing catalyst loading, PMS dosage, and pH. Meanwhile, the dominant reactive oxygen species was identified using the chemical scavengers with SO₄^•-, ^•OH, and ¹O₂ playing a major role in CIP degradation. The performance of BFCuO-0.08 deteriorated in real water matrix (tap water, river water and secondary effluent) due to the presence of various water matrix species. Nevertheless, the BFCuO-0.08 catalyst possessed remarkable stability and can be reused for at least four successive cycles with >70% of CIP degradation efficiency indicating that it is a promising catalyst for antibiotics removal.

Recent Development Strategies for Bismuth-Driven Materials in Sustainable Energy Systems and Environmental Restoration

Bismuth(Bi)-based materials have gained considerable attention in recent decades for use in a diverse range of sustainable energy and environmental applications due to their low toxicity and eco-friendliness. Bi materials are widely employed in electrochemical energy storage and conversion devices, exhibiting excellent catalytic and non-catalytic performance, as well as CO₂ /N₂ reduction and water treatment systems. A variety of Bi materials, including its oxides, chalcogenides, oxyhalides, bismuthates, and other composites, have been developed for understanding their physicochemical properties. In this review, a comprehensive overview of the properties of individual Bi material systems and their use in a range of applications is provided. This review highlights the implementation of novel strategies to modify Bi materials based on morphological and facet control, doping/defect inclusion, and composite/heterojunction formation. The factors affecting the development of different classes of Bi materials and how their control differs between individual Bi compounds are also described. In particular, the development process for these material systems, their mass production, and related challenges are considered. Thus, the key components in Bi compounds are compared in terms of their properties, design, and applications. Finally, the future potential and challenges associated with Bi complexes are presented as a pathway for new innovations.

One-pot synthesis of TEA functionalized and NiSe embedded rGO nanocomposites for supercapacitor application

NiSe and NG-NiSe (triethanolamine functionalized and NiSe embedded rGO), as electrode materials for supercapacitor application, were prepared by a hydrothermal technique. XRD confirmed the formation of pure NiSe and NG-NiSe nanocomposites, which showed a hexagonal crystalline structure of NiSe. The structural morphology and particle size of NiSe and NG-NiSe were measured using FESEM and HRTEM analysis, respectively. The oxidation states and elemental compositions of NG-NiSe were investigated by XPS. The electrochemical behaviours of the materials were studied using CV, GCD, and EIS spectra. NG-NiSe showed higher capacitance performance compared to pure NiSe, due to the synergetic effects on the rGO/TEA/NiSe nanocomposite during one-pot synthesis. The energy density and power density of a N-rGO//NG-NiSe asymmetric cell were 28.25 W h kg^-1 and 700 W kg^-1, respectively.