Supercapatteries as Hybrid Electrochemical Energy Storage Devices: Current Status and Future Prospects

Among electrochemical energy storage (EES) technologies, rechargeable batteries (RBs) and supercapacitors (SCs) are the two most desired candidates for powering a range of electrical and electronic devices. The RB operates on Faradaic processes, whereas the underlying mechanisms of SCs vary, as non-Faradaic in electrical double-layer capacitors (EDLCs), Faradaic at the surface of the electrodes in pseudo-capacitors (PCs), and a combination of both non-Faradaic and Faradaic in hybrid supercapacitors (HSCs). EDLCs offer high power density but low energy density. HSCs take advantage of the Faradaic process without compromising their capacitive nature. Unlike batteries, supercapacitors provide high power density and numerous charge-discharge cycles; however, their energy density lags that of batteries. Supercapatteries, a generic term that refers to hybrid EES devices that combine the merits of EDLCs and RBs, have emerged, bridging the gap between SCs and RBs. There are numerous articles and reviews on EES, and many of those articles have emphasized various aspects of HSCs and supercapatteries. However, there are no recent reviews that dealt with supercapatteries in general. Here, we review recently published critically selected articles on supercapatteries. The review discusses different EES devices and how supercapatteries are different from others. Also discussed are properties, design strategies, and future perspectives on supercapatteries.

Hierarchical bismuthyl bromide microspheres assembled by laminas as efficient negative material for aqueous alkali battery

Bismuth (Bi) based compounds are promising negative materials in aqueous alkali batteries (AABs) for the 3-electron redox chemistry of Bi element within low potentials, the exploration of new Bi-based negative materials is still a meaningful work in this field. Herein, a hierarchical bismuthyl bromide (BiOBr) microspheres material assembled by laminas was prepared via solvothermal reaction and attempted as negative battery material for AAB. The pronounced redox reactions of Bi species in low potential enable high battery capacity, and the porous texture with high hydrophilicity facilitates diffusion of OH- and participation in faradaic reactions. When used as negative battery electrode, the BiOBr could offer decent specific capacity (Cs, 190 mAh g-1 at 1 A g-1), rate capability (Cs remained to 163 mAh g-1 at 8 A g-1) and cycleability (85% Cs retention after 1000 charge-discharge cycles). The AAB based on BiOBr negative electrode could export an energy density (Ecell) of 61.5 Wh kg-1 at power density (Pcell) of 558 W kg-1 and good cycleability. The current work showcases valuable application expansion of a traditional BiOBr photocatalyst in battery typed charge storage.

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.

Microwave-Assisted Hierarchically Grown Flake-like NiCo Layered Double Hydroxide Nanosheets on Transitioned Polystyrene towards Triboelectricity-Driven Self-Charging Hybrid Supercapacitors

Recently, there is a need to explore the utilization of various heterostructures using the designed nanocomposites and tuning the surfaces of electrodes for improving the electrochemical performance of supercapacitors (SC). In this work, a novel approach is successfully employed through a facile two-step synthetic route with the assistance of a microwave for only 1 min. Depending on the glass transition of a polystyrene (PS) substrate and electrochemical deposition (ECD) of electroactive Ni-Co layered double hydroxides (LDHs), a hierarchically designed flake-like morphology can be readily prepared to enhance the surface-active sites, which allows a rhombohedral Ni-Co LDHs electrode to obtain superior electrochemical properties. Further, the interactions between electrode and electrolyte during the diffusion of ions are highly simplified using multiple enhanced electroactive sites and shorter pathways for electron transfer. The unique surface architecture of the PS substrate and the synergistic effect of the bimetallic components in Ni-Co LDHs enable this substrate to obtain desired electrochemical activity in charge storage systems. The optimized MWC Co_0.5Ni_0.5 electrode exhibited an areal capacity of 100 µAh/cm² at a current density of 1 mA/cm² and a remarkable capacity retention of 91.2% over 5000 continuous charging and discharging cycles due to its remarkable synergistic effect of abundant faradaic redox reaction kinetics. The HSC device is assembled with the combination of optimized MWC Co_0.5Ni_0.5 and activated carbon as a positive and negative electrode, respectively. Further, the electrochemical test results demonstrated that MWC Co_0.5Ni_0.5 //AC HSC device showed a high areal capacitance of 531.25 mF/cm² at a current density of 5 mA/cm². In addition, the fabricated an aqueous HSC device showed a power density of 16 mW/cm² at an energy density of 0.058 mWh/cm², along with the remarkable capacity retention of 82.8% even after 10,000 continuous charging and discharging cycles. Moreover, the assembled hybrid supercapacitor (HSC) device is integrated with a triboelectric nanogenerator (TENG) for the development of energy conversion and storage systems. Not only an extensive survey of materials but also an innovative solution for recent progress can confirm the wide range of potential SC applications. Remarkably, this study is a new way of constructing self-powered energy storage systems in the field of sustainable wearable electronics and future smart sensing systems.

High-performance aqueous rechargeable nickel//bismuth batteries with Bi2MoO6@rGO and Co0.5Ni0.5MoO4@rGO as electrode materials

Aqueous rechargeable nickel–bismuth batteries have surfaced as a prospective energy storage and conversion system because of their merits of good safety, high power density, and low cost.

New bismuth oxyiodide/chitosan nanocomposite for ultrasonic waves expedited adsorptive removal of amoxicillin from aqueous medium: kinetic, isotherm and thermodynamic investigations

Amoxicillin (AMX) is a widely used antibiotic, which induces harmful effects to nature via bioaccumulation and persistence in the environment if discharged untreated into water bodies. In the current study, a novel bionanocomposite, bismuth oxyiodide-chitosan (BiOI-Ch), was synthesized by a facile precipitation method and its amoxicillin (AMX) adsorption capacity in the presence of ultrasonic waves has been explored. Multiple batch experiments were performed to achieve the optimum operational parameters for maximum adsorption of AMX and the obtained results were as follows: pH 3, 80 mg g^-1 AMX concentration, 1.7 g L^-1 adsorbent dose, temperature 298 K and ultrasonication time 20 min. Composite removed approximately 90% AMX from the solution under optimized conditions, while the maximal adsorption capacity was determined to be 81.01 mg g^-1. BiOI-Ch exhibited superior adsorption capacity as compared to pure BiOI (33.78 mg g^-1). To understand the dynamics of reaction, several kinetic and isotherm models were also examined. The adsorption process obeyed pseudo-second-order kinetic model (R² = 0.98) and was well fitted to Freundlich isotherm (R² = 0.99). The addition of biowaste chitosan to non-toxic bismuth-based nanoparticles coupled with ultrasonication led to enhanced functional groups as well as surface area of the nanocomposite resulting in superior adsorption capacity, fast adsorption kinetics and improved mass transfer for the removal of AMX molecules. Thus, this study demonstrates the synergistic effect of ultrasonication in improved performance of novel BiOI-Ch for potential application in the elimination of persistent and detrimental pollutants from industrial effluent after necessary optimization for large-scale operation.

Bi-Fe chalcogenides anchored carbon matrix and structured core-shell Bi-Fe-P@Ni-P nanoarchitectures with appealing performances for supercapacitors

Pseudocapacitive materials based on multi-active components are attractive platforms for future portable energy devices due to their excellent redox processes and low cost. In this study, nanostructured bismuth-iron chalcogenide anchored on multiwalled carbon nanotube framework (Bi-Fe chalcogenide/C)-based electrode materials were fabricated via a simple solvothermal protocol with enhanced electrochemical performances. The obtained Bi-Fe chalcogenide/C nanocomposites combining the improved electroconductivity of carbonic frameworks and high pseudocapacitive properties of Bi/Fe reversible redox processes were employed as negative electrodes for asymmetric supercapacitor (ASC) devices. Systematic investigation of the synthesized materials and capacitive performance indicated that the Bi-Fe-P/C electrode simultaneously achieved an intrinsically appreciable specific capacitance of 532 F g^-1 at a current density of 1 A g^-1, high-rate capability, and cyclic stability, profiting from the structural and amorphous merits as well as the collaborative effect of multiple components. Besides, we employed an effective strategy to graft Bi-Fe-P film on a self-standing nickel phosphide (Ni-P) to manufacture a cathode with superior capacitive performances. The as-prepared core-shell Bi-Fe-P@Ni-P was used as a high-performance positive electrode and displayed a large specific capacitance of 230.6 mAh g^-1 at 1 A g^-1. Additionally, we also assembled an ASC system using the core-shell Bi-Fe-P@Ni-P as a positive electrode and amorphous Bi-Fe-P/C as a negative electrode with an expanded operational potential of 1.6 V. The hybrid device delivered a high specific energy density of 81.5 Wh kg^-1 at a power density of 890.2 W kg^-1 together with good cyclic characteristics (85.6% capacitance retention after 8000 consecutive cycles). The obtained findings offer new insights into the design of advanced energy storage materials at relatively low costs and underscore the proficiency of heterostructured multicomponent electrodes as a practical option for enhancing the electrochemical performance of ASC.

Self-templating Scheme for the Synthesis of NiCo2Se4 and BiSe Hollow Microspheres for High-energy Density Asymmetric Supercapacitors

Porous hollow structure of the electrode materials can enlarge the surface area in contact with the electrolyte, accelerating the transport of ions and electrons during redox reaction to enhance electrochemical...