Search Results (19)

Zinc–manganese dioxide (Zn–MnO₂) batteries, pivotal in primary energy storage, face challenges in rechargeability due to cathode dissolution and anode corrosion. This review summarizes cathode-free designs using pH-optimized electrolytes and modified electrodes/current collectors. For electrolytes, while acidic systems with additives (PVP, HAc) enhance ion transport, dual-electrolyte configurations (ion-selective membranes/hydrogels) reduce Zn corrosion. Near-neutral strategies utilize nanomicelles/complexing agents to regulate MnO₂ deposition. Moreover, mediators (I⁻, Br⁻, Cr³⁺) reactivate MnO₂ but require shuttle-effect control. For the electrodes/current collectors, electrode innovations including SEI/CEI layers and surfactant-driven phase tuning are introduced. Electrode-free designs and integrated “supercapattery” systems combining supercapacitors with Zn–MnO₂/I₂ chemistries are also discussed. This review highlights electrolyte–electrode synergy and hybrid device potential, paving the way for sustainable, high-performance Zn–MnO₂ systems. Full article

A highly redox-active ternary nickel sulfide and cobalt-anchored carbon nanocomposite (NiS-Co@C) electrochemical electrode is synthesized by a two-step pyrolysis-hydrothermal method using biomass-derived carbon. The high-crystalline hierarchical porous nanostructure provides abundant voids and cavities, along with a large specific surface area, to improve the interfacial properties. The as-synthesized electrode achieved a specific capacity of 640 C g⁻¹ at 1 A g⁻¹, with a capacity retention of 93% over 5000 cycles, revealing outstanding electrochemical properties. Nickel sulfide nanoparticles embedded in the cobalt-anchored carbon framework improved redox activity, ion transport, and conductivity, resulting in a dominant diffusion-controlled battery-type behavior. Moreover, a hybrid supercapattery, based on battery-type NiS-Co@C as the positrode and capacitive-type activated carbon as the negatrode, achieved a maximum specific energy/power of 33 Wh kg⁻¹/7.1 kW kg⁻¹ with a 91% capacity retention after 5000 cycles. The synergistic effect of the combinatorial battery–capacitor behavior of the hybrid supercapattery has improved the specific energy–power considerably, leading the development of next-generation energy storage technologies. Full article

Achieving high energy density while maintaining high power density and long cycle life in supercapacitors, particularly in supercapatteries (SCs), through a thermally stable, greener ionic liquid approach remains a significant challenge for an advanced energy storage application. In this work, we prepared high conductive and high charge storage capability bimetallic transition metal molybdate [Ag₂Mo₂O₇ (AgM)], synergistic with reduced graphene oxide (rGO) coated on nickel foam (AgM/rGO/NF). The physio-chemical characterization revealed a ball-like cluster morphology wrapped in rGO nanosheets and a spinel-type cubic structure using scanning electron microscopy (FE-SEM) displays and X-ray diffraction (XRD) analyses. Further, the electrochemical performance of AgM/rGO/NF electrode achieved a remarkable specific C_sp value of 573.63 F/g at a current density of 1.0 A/g in 3 M KOH electrolyte. An asymmetric SCs (ASCs) device was fabricated using AgM/rGO/NF as the positive and rGO as the negative electrodes, achieving a wide potential window of 1.3 V. The ASC demonstrated an energy density of 16.71 Wh/kg at a power density of 642.98 W/kg, highlighting AgM/rGO/NF’s potential as an advanced electrode material for energy storage applications. Full article

Metal sulfide-based composites have become increasingly common as materials used for electrodes in supercapacitors because of their excellent conductivity, electrochemical activity, and redox capacity. This study synthesized a composite of NiFeS@MoS₂@rGO nanostructure using a simple hydrothermal approach. The synthesized nanocomposite consisted of the composite of nickel sulfide and iron sulfide doped with MoS₂@rGO. A three-electrode cell is employed to investigate the electrochemical properties of the NiFeS@MoS₂@rGO electrode. The results demonstrated an optimal specific capacitance of 3188 F/g at 1.4 A/g in a 1 M KOH electrolyte. Furthermore, a supercapattery is designed utilizing NiFeS@MoS₂@rGO//AC as the positive electrode and activated carbon (AC) as the negative electrode materials. The resulting supercapattery is designed at a cell voltage of 1.6 V, achieving a specific capacity value of 189 C/g at 1.4 A/g. It also demonstrated an excellent energy density of 55 Wh/kg with an enhanced power density of 3800 W/kg. Furthermore, the hybrid device demonstrated remarkable stability with a cycling stability of 95% over 30,000 charge–discharge cycles at a current density of 1.4 A/g. The supercapattery, which has excellent energy storage capabilities, is used as a power source for operating different portable electronic devices. Full article

This review article focuses on the potential of cobalt oxide composites with conducting polymers, particularly polypyrrole (PPy) and polyaniline (PANI), as advanced electrode materials for supercapacitors, batteries, and supercapatteries. Cobalt oxide, known for its high theoretical capacitance, is limited by poor conductivity and structural degradation during cycling. However, the integration of PPy and PANI has been proven to enhance the electrochemical performance through improved conductivity, increased pseudocapacitive effects, and enhanced structural integrity. This synergistic combination facilitates efficient charge transport and ion diffusion, resulting in improved cycling stability and energy storage capacity. Despite significant progress in synthesis techniques and composite design, challenges such as maintaining structural stability during prolonged cycling and scalability for mass production remain. This review highlights the synthesis methods, latest advancements, and electrochemical performance in cobalt oxide/PPy and cobalt oxide/PANI composites, emphasizing their potential to contribute to the development of next-generation energy storage devices. Further exploration into their application, especially in battery systems, is necessary to fully harness their capabilities and meet the increasing demands of energy storage technologies. Full article

The overconsumption of fossil fuels is leading to worsening environmental damage, making the generation of clean, renewable energy an absolute necessity. Two common components of electrochemical energy storage (EES) devices are batteries and supercapacitors (SCs), which are among the most promising answers to the worldwide energy issue. In this study, we introduce an exceptionally efficient electrode material for supercapacitors, composed of a hydrothermally synthesized composite known as MnNiS@MXene. We utilized XRD, SEM, and BET to analyze the material’s crystallinity, morphology, and surface area. The Qs of MnNiS@MXene was a remarkable 1189.98 C/g or 1983.3 F/g at 2 A/g under three electrode assemblies in 1 M KOH electrolyte solution. Activated carbon was used as the negative electrode, while MnNiS@MXene served as the positive electrode in the assembled supercapattery device (MnNiS@MXene//AC). This device showed exceptional performance, a specific capacity of 307.18 C/g, a power density of 1142.61 W/kg, and an energy density of 34.79 Wh/kg. Additionally, cyclic durability was evaluated through 7000 cycles of charging/discharging, demonstrating that it maintained approximately 87.57% of its original capacity. The successful integration of these materials can lead to electrodes with superior energy storage capabilities and efficient photoelectrochemical performance. The aforementioned findings suggest that MnNiS@MXene exhibits promising potential as an electrode material for forthcoming energy storage systems. Full article

Battery-type hybrid supercapacitors (HSCs) (otherwise known as supercapatteries) are novel electrochemical energy storage devices bridge the gap between rechargeable batteries and traditional SCs. Herein, we report the synthesis of layered two-dimensional (2D) nickel disulfide (NiS₂) nanosheets (NSNs) modified with poly(3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS) and their successful implementation in battery-type SCs. Initially, a layered 2D NSN is synthesized via a microwave-assisted hydrothermal method and further used as a template to coat PEDOT:PSS in order to prepare NiS₂@PEDOT:PSS nanocomposite electrodes by a facile drop-casting method. This is the first-time report on the synthesis of a hierarchical NiS₂@PEDOT:PSS nanocomposite electrode for battery-type HSC applications. An asymmetric battery-type HSC fabricated with NSN@PEDOT:PSS nanocomposite as positrode and activated carbon as negatrode delivers a maximum energy density of 52.1 Wh/kg at a current density of 1.6 A/g with a corresponding power density of 2500 W/kg. Full article

Two-dimensional (2D) sulfide-based transition metal dichalcogenides (TMDs) have shown their crucial importance in energy storage devices. In this study, the tungsten disulfide (WS₂) nanosheets were combined with hydrothermally synthesized cobalt magnesium sulfide (CoMgS) nanocomposite for use as efficient electrodes in supercapattery energy storage devices. The characteristics of the WS₂@CoMgS nanocomposite were better than those of the WS₂ and CoMgS electrodes. XRD, SEM, and BET analyses were performed on the nanocomposite to examine its structure, morphology, and surface area in depth. In three-electrode assemblies, the composite (WS₂@CoMgS) electrode showed a high specific capacity of 874.39 C g⁻¹ or 1457.31 F g⁻¹ at 1.5 A g⁻¹. The supercapattery device (WS₂@CoMgS//AC) electrode demonstrated a specific capacity of 325 C g⁻¹ with an exceptional rate capability retention of 91% and columbic efficiency of 92% over 7000 cycles, according to electrochemical studies. Additionally, the high energy storage capacity of the WS₂@CoMgS composite electrode was proved by structural and morphological investigations. Full article

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. Full article

The copper-based metal-organic framework (HKUST-1) exhibits interesting properties, such as high porosity and large specific surface area, which are useful as electrode materials for supercapattery. Herein, the HKUST-1 was synthesized through a facile hydrothermal method and exhibited a typical octahedral structure with a specific surface area of 1015.02 m² g⁻¹, which was calculated using the Barrett–Joyner–Halenda (BJH) method. From the three-electrode analysis, the HKUST-1 demonstrated a specific capacity of 126.2 C g⁻¹ in 1 M LiOH. The structural fingerprint of the HKUST-1 was confirmed with Fourier-transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction spectroscopy. A supercapattery device, i.e., the HKUST-1//N-doped graphene, revealed a maximum specific power of 300 W kg⁻¹ and a specific energy of 2.61 W h kg⁻¹ at 1 A g⁻¹ with 57% capacitance retention during continuous charging–discharging, even after 10,000 cycles. The HKUST-1 also demonstrated a low charge transfer resistance and a low equivalent series resistance of 7.86 Ω and 0.87 Ω, respectively, verifying its good conductivity. The prominent supercapattery performance of the HKUST-1//N-doped graphene suggested that the HKUST-1 is a promising positive electrode for supercapattery. Full article

To make supercapattery devices feasible, there is an urgent need to find electrode materials that exhibit a hybrid mechanism of energy storage. Herein, we provide a first report on the capability of lithium manganese sulfates to be used as supercapattery materials at elevated temperatures. Two compositions are studied: monoclinic Li₂Mn(SO₄)₂ and orthorhombic Li₂Mn₂(SO₄)₃, which are prepared by a freeze-drying method followed by heat treatment at 500 °C. The electrochemical performance of sulfate electrodes is evaluated in lithium-ion cells using two types of electrolytes: conventional carbonate-based electrolytes and ionic liquid IL ones. The electrochemical measurements are carried out in the temperature range of 20–60 °C. The stability of sulfate electrodes after cycling is monitored by in-situ Raman spectroscopy and ex-situ XRD and TEM analysis. It is found that sulfate salts store Li⁺ by a hybrid mechanism that depends on the kind of electrolyte used and the recording temperature. Li₂Mn(SO₄)₂ outperforms Li₂Mn₂(SO₄)₃ and displays excellent electrochemical properties at elevated temperatures: at 60 °C, the energy density reaches 280 Wh/kg at a power density of 11,000 W/kg. During cell cycling, there is a transformation of the Li-rich salt, Li₂Mn(SO₄)₂, into a defective Li-poor one, Li₂Mn₂(SO₄)₃, which appears to be responsible for the improved storage properties. The data reveals that Li₂Mn(SO₄)₂ is a prospective candidate for supercapacitor electrode materials at elevated temperatures. Full article

Electrolytes are one of the most influential aspects determining the efficiency of electrochemical supercapacitors. Therefore, in this paper, we investigate the effect of introducing co-solvents of ester into ethylene carbonate (EC). The use of ester co-solvents in ethylene carbonate (EC) as an electrolyte for supercapacitors improves conductivity, electrochemical properties, and stability, allowing greater energy storage capacity and increased device durability. We synthesized extremely thin nanosheets of niobium silver sulfide using a hydrothermal process and mixed them with magnesium sulfate in different wt% ratios to produce Mg(NbAgS)_x)(SO₄)_y. The synergistic effect of MgSO₄ and NbS₂ increased the storage capacity and energy density of the supercapattery. Multivalent ion storage in Mg(NbAgS)_x(SO₄)_y enables the storage of a number of ions. The Mg(NbAgS)_x)(SO₄)_y was directly deposited on a nickel foam substrate using a simple and innovative electrodeposition approach. The synthesized silver Mg(NbAgS)_x)(SO₄)_y provided a maximum specific capacity of 2087 C/g at 2.0 A/g current density because of its substantial electrochemically active surface area and linked nanosheet channels which aid in ion transportation. The supercapattery was designed with Mg(NbAgS)_x)(SO₄)_y and activated carbon (AC) achieved a high energy density of 79 Wh/kg in addition to its high power density of 420 W/kg. The supercapattery (Mg(NbAgS)_x)(SO₄)_y//AC) was subjected to 15,000 consecutive cycles. The Coulombic efficiency of the device was 81% after 15,000 consecutive cycles while retaining a 78% capacity retention. This study reveals that the use of this novel electrode material (Mg(NbAgS)_x(SO₄)_y) in ester-based electrolytes has great potential in supercapattery applications. Full article

In this work, silver (Ag) anchored over graphene (GN) wrapped polypyrrole (PPy)@ nickel hydroxide (Ni(OH)₂) nanocomposites were synthesized through a combination of oxidative polymerization and hydrothermal processes. The synthesized Ag/GN@PPy–Ni(OH)₂ nanocomposites were characterized for their morphological characteristics by field emission scanning electron microscopy (FESEM), while the structural investigations were done by X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The FESEM studies showed Ni(OH)₂ flakes and silver particles attached over the surface of PPy globules, along with the presence of GN sheets and spherical silver particles. The structural analysis also showed the presence of constituents, i.e., Ag, Ni(OH)₂, PPy, GN, and their interaction, therefore vouching that the synthesis protocol is efficacious. The electrochemical (EC) investigations were done in potassium hydroxide (1 M KOH) using a three electrode setup. The quaternary Ag/GN@PPy–Ni(OH)₂ nanocomposite electrode showed the highest specific capacity of 237.25 C g⁻¹. The highest electrochemical performance of the quaternary nanocomposite is associated with the synergistic/additional effect of PPy, Ni(OH)₂, GN, and Ag. The assembled supercapattery with Ag/GN@PPy-Ni(OH)₂ as a positive and activated carbon (AC) as a negative electrode displayed eminent energy density of 43.26 Wh kg⁻¹ with the associated power density of 750.00 W kg⁻¹ at a current density of 1.0 A g⁻¹. The cyclic stability of the supercapattery (Ag/GN@PPy–Ni(OH)₂//AC), comprising a battery-type electrode, displayed a high cyclic stability of 108.37% after 5500 cycles. Full article

Polyaniline (PANI), due to its highly reversible electrochemistry with superior energy storage and delivery characteristics, is considered as an electrode material in batteries, capacitors, and hybrid systems. We used a facile electrochemical synthesis for the formation of the PANI electrode using galvanostatic polymerization of aniline on the graphite electrode at the current density of 2.0 mA cm⁻² from the aqueous electrolyte containing 0.25 mol dm⁻³ aniline and 1.0 mol dm⁻³ H₂SO₄. Electrochemical and electrical characterization suggested excellent energy storage features of the PANI electrode in a three-electrode system with specific energy up to 53 Wh kg⁻¹ and specific power up to 7600 W kg⁻¹. After 2000 successive charge/discharge cycles at 9.5 Ag⁻¹, the PANI electrode retained 95% of the initial capacity, with practically unaltered Coulombic efficiency of nearly 98%, providing a good base for future studies and practical applications. Full article

In this work, NiCo₂S₄–graphene hybrids (NCS@G) with high electrochemical performance were prepared using a hydrothermal method. The response surface methodology (RSM), along with a central composite design (CCD), was used to investigate the effect of independent variables (G/NCS, hydrothermal time, and S/Ni) on the specific capacitances of the NCS@G/Ni composite electrodes. RSM analysis revealed that the developed quadratic model with regression coefficient values of more than 0.95 could be well adapted to represent experimental results. Optimized preparation conditions for NCS@G were G/NCS = 6.0%, hydrothermal time = 10.0, and S/Ni = 6.0 of NCS@G (111) sample. The maximum specific capacitance of NCS@G (111)/Ni fabricated at the optimal condition is about 216% higher than the best result obtained using the conventional experimental method. The enhanced capacitive performance of the NCS@G (111) sample can be attributed to the synergistic effect between NCS nanoparticles and graphene, which has the meso/macropores conductive network and low diffusion resistance. Notably, the NCS@G (111) could not only provide numerous reaction sites but also prevent the restacking of graphene layers. Furthermore, a supercapattery cell was fabricated with an (G + AC)/Ni anode, a NCS@G (111)/Ni cathode, and a carboxymethyl cellulose–potassium hydroxide (CMC-KOH) gel electrolyte. The NCS@G (111)//(G + AC) demonstrates an outstanding energy density of 80 Wh kg⁻¹ at a power density of 4 kW kg⁻¹, and a good cycling performance of 75% after 5000 cycles at 2 A g⁻¹. Applying the synthesis strategy of RSM endows remarkable capacitive performance of the hybrid materials, providing an economical pathway to design promising composite electrode material and fabricate high-performance energy storage devices. Full article