Class Of Energy Storage Devices Research Articles

V2O5 coral microspheres: High performance electrode material for Li-ion supercapacitor

Energy storage devices forms lifeline for most modern devices. The short life cycle and lower power density of batteries has prompted development of supercapacitors as potential alternatives. Li-ion supercapacitors, is an emerging class of energy storage devices. Natural abundance and availability of variable oxidation states make V2O5 an attractive electrode material. Here, we report synthesis of coral microspheres of V2O5 using low temperature solvothermal technique, as electrode material for Li-ion supercapacitor. The annealing temperature plays a cucial role in formation of microspherical aggregates, dictates their surface area and hence the energy storage performance. Samples annealed at 400 °C showed specific capacitance of ∼360 F/g at current density of 0.5 A/g. Our studies suggest that V2O5 based nanostructures holds significant potential for development of hybrid Li-ion supercapacitors.

Understanding the Diffusion‐Dominated Properties of MOF‐Derived Ni–Co–Se/C on CuO Scaffold Electrode using Experimental and First Principle Study

AbstractBatteries and supercapacitors continue to be one of the most researched topics in the class of energy storage devices. The continuous development of battery and supercapacitor cell components has shown promising development throughout the years—from slabs of pure metal to porous and tailored structures of metal‐based active materials. In this direction, metal–organic frameworks (MOFs) serve great advantages in improving the properties and structure of the derived metal‐based active materials. This research provides a novel electrode material, Ni–Co–Se/C@CuO, derived from Ni–Co‐MOF integrated with pre‐oxidized Cu mesh. The superior electrochemical performance of Ni–Co–Se/C@CuO over Ni–Co‐MOF@CuO is evident through its higher specific capacity, lower resistivity, richer redox activity, and more favorable diffusion‐dominated storage mechanism. When assembled as a hybrid supercapacitor (HSC), the hybrid device using rGO and Ni–Co–Se/C@CuO as electrodes exhibits a high energy density of 42 W h kg−1 at a power density of 2 kW kg−1, and maintains its capacity retention even after 20 000 cycles. The improved capacity performance is also evaluated using first‐principle investigations, revealing that the unique and preserved heterostructure of Ni–Co–Se/C@CuO portrays enhanced metallic properties. Such evaluation of novel electrodes with superior properties may benefit next‐generation electrodes for supercapacitor devices.

(Digital Presentation) Ionic Liquid-Based Electrolytes for Evaluation of Anthraquinone Derivative As Cathode in Zinc Ion Battery

Aqueous zinc ion batteries are a very promisingly emerging class of energy storage devices. They are brought to the attention of the researchers owing to the abundant resourcefulness, user and environmental friendliness, and excellent water compatibility unlike the alkaline and alkaline earth metals. Unfortunately, their research and development are still in the unmatured stage. Few of the inorganic materials, such as oxides of manganese, vanadium, Prussian blue, etc., are some of the inorganic materials evaluated as cathode for zinc batteries. Even though inorganic materials offer high energy density which directly affects the size of the battery, they face some serious constraints of being used for real practical applications. They undergo irreversible structural lattice changes during the cycling process which ultimately deteriorate the battery performance over prolonged cycling. In addition, they face serious dissolution problems, lack of resourcefulness, and environmental non-benignity. In this regard, organic cathodes are interesting candidates because of their flexibility, simple charge storage mechanism, numerous choices of molecular engineering, and high resourcefulness. Herein, we studied the anthraquinone derivative as an organic cathode in ionic liquid electrolytes. Even though aqueous electrolytes are user-friendly, excessive water evaporation occurs with subsequent salt crystallization on the electrode which deteriorates the battery performance. We previously reported on addressing the restriction of water evaporation by choosing ethylene glycol as an electrolyte additive. Since ionic liquid exists as a liquid at room temperature, we selected different types of ILs, ie., imidazole containing different types of alkyl and functionalized alkyl chains as shown in the figure.This work essentially emphasizes the aqueous zinc battery performance using functionalized ionic liquids as electrolytes with a newly designed anthraquinone-based organic cathode. It has been observed that the zwitterionic electrolyte exhibited comparatively good capacity performance of 156.2 mAhg-1 at 50 mAg-1 current density. The cycling stability, as well as coulombic efficiency, were also found to be much promising. On the whole, user-friendly organic-based electrolyte, as well as organic cathode, converge a new integrated electrode-electrolyte system for zinc ion battery. The detailed battery performance and post-mortem analysis have also been performed which reinvigorate the battery research, for zinc-like multivalent ion-based batteries in particular. Figure 1

A reign of bio-mass derived carbon with the synergy of energy storage and biomedical applications

The high specific surface area and suitable pore size distribution of carbon based electrodes significantly improves the energy and power density of energy storage devices. The present study details the development of eco-friendly and low-cost carbon material containing fluorine (F) atoms prepared from biomass Ipomoea carnea flower (IC). The favourably developed carbon material is used as electrode for lithium‑sulfur batteries (LSBs), supercapacitors and biomedical application of the same is explored. Owing to its high theoretical specific capacity, high energy density and low production cost, LSBs are recognised as propitious class of energy storage devices. The detriments like fast capacity fading arising due to insulating nature, shuttle effect and volume expansion of sulfur electrode is surmount by employing ternary composite of sulfur/silicon dioxide/IC (SSIC) as cathode for LSBs. The outcome of this work reveals that polysulfides are confined both physically and chemically by highly electronegative F atoms present in IC along with SiO2, thereby alleviating shuttle effect and demonstrates better electrochemical performance. SIC electrode exhibited a coulombic efficiency of 95%, whereas SSIC electrode delivered efficiency of 99.5% after entire cycling life. Here, IC carbon matrix is also employed as electrode material for supercapacitor device which delivered specific capacitance up to 382 F g−1 which is outstanding when compared to capacitances from other reported carbon supercapacitors. The cytotoxicity of IC carbon is analysed by co-culturing IC carbon with human breast cancer cells (MCF-7 cell line). The cell death is observed in the IC50 concentration of 56.23 μg/ mL.

Emergence of Novel 2D Materials for High-Performance Supercapacitor Electrode Applications: A Brief Review

Energy storage and production is one of the significant issues of the 21st century, motivating the search for new materials for energy storage devices. Supercapacitors (SCs) play a prominent role among the class of energy storage devices and conversion systems since they provide greater specific capacitance, high power density, longer life span, fast charge–discharge rate, excellent circulation feature, low cost, and are safe to use. The selection of electrode material has great importance in the performance of the supercapacitor. Two-dimensional (2D) layered nanomaterials gained much interest in the fabrication of electrode materials due to their unique physicochemical properties. The current review explores the synthesis and application of novel 2D materials, such as graphene, MXene, transition metal dichalcogenides (TMDs), hexagonal boron nitride (h-BN), carbon nitrides, metal oxides/hydroxides, and black phosphorus (BP), as supercapacitor electrodes in detail.

A novel flexible wire-shaped supercapacitor with enhanced electrochemical performance based on hierarchical Co(OH)2@Ni(OH)2 decorated porous dendritic Ni film/Ni wire

Wire-shaped supercapacitors, a new class of energy storage devices, have recently received enormous attention advantages of miniature size, lightweight and high flexibility. However, most of the reported wire-shaped supercapacitors are still suffered from low specific capacitance and limited energy densities as well as the relatively poor electrochemical performance. In this research, Co(OH)2@Ni(OH)2 nanosheets were successfully synthesized on the 3D-Ni film-coated Ni wire (NW) by electrochemical methods. The electrochemical tests of Co(OH)2@Ni(OH)2/3D-Ni/NW electrode confirmed the outstanding supercapacitive behavior of nanostructures with excellent cycling stability. This behavior could be attributed to 3D network structure of Ni film and the nanosheets which allow facile electrolyte and electrons transportation. Detailed electrochemical characterization shows that the Co(OH)2@Ni(OH)2/3D-Ni/NW exhibits a high specific capacitance of 355.2 C g–1 at current density of 1 Ag–1 and excellent cycle performance (80.0% retention after 3000 CD cycles). Also, the maximum energy density of 27.24 W h kg–1 at the power density of 234.99 W kg–1 was measured. The obtained results reveal that the Co(OH)2@Ni(OH)2 core-shell can be a promising electroactive material for supercapacitors. This unique supercapacitor opens up a new path in the development of fiber-shaped energy storage apparatuses.

Unraveling the Charge-Storage Mechanism in High-Performance Zinc-Ion Hybrid Supercapacitors

The crucial request for alternative clean energy technologies to replace conventional fossil fuels and drive technological advancement in consumer and wearable electronics, electric vehicles etc. has led to great advancement in electrochemical energy storage systems research. The lithium-ion battery possesses high energy density while the supercapacitor can guarantee high power density. However, modern technologies such as integrated solar and wind energy solutions require a blend of high energy and power density devices, which is a great challenge. Presently, there is increased research interest in aqueous hybrid supercapacitors, a device capable of combining the high energy density of rechargeable batteries and the high-power density of electric-double layer capacitors.The current hotspot of the hybrid supercapacitor research is the zinc-ion hybrid supercapacitor owing to its several advantages such as the abundance of Zinc resource over lithium, high theoretical capacity of Zn, double charge transfer compared to univalent Lithium, environmental safety and high energy/power density. Wang et al first reported the carbon zinc-ion hybrid supercapacitor in 2018 by directly using zinc foil as anode and bio-carbon as cathode to realize long stability up to 20000 cycles. Next, Dong et al also developed an activated carbon-based zinc-ion hybrid supercapacitor which achieved a high energy density of ~84 Wh kg-1 and power density of 14.9 kW kg-1 in a potential window of 0.2 – 1.8 V. Despite the rapid advances over a short period in this class of energy storage devices, some problems still exist. The coulombic efficiency of Zinc-ion hybrid supercapacitors is inferior in low-cost ZnSO4 electrolytes owing to side reactions between the electrolyte and the Zn anode, while the mass loading of commonly used carbon cathode is extremely low (less than 2 mg cm-2). Importantly, the charge storage mechanism in zinc-ion hybrid supercapacitors is unclear.In this work, we developed high performance zinc-ion hybrid supercapacitors with superior charge storage, improved rate capability, and high power and energy density using a high mass density carbon anode with superior capacitive/pseudocapacitive storage. We successfully reveal that the charge storage of zinc-ion hybrid supercapacitors is extensively limited in zinc sulfate electrolytes and successfully address the coulombic efficiency problem using by modifying the electrolyte. Finally, using techniques such as in-situ Raman spectroscopy and X-ray diffraction analysis, we probe the charge storage mechanism and unravel a double cation charge storage mechanism, resulting in high energy density and extended potential window. Finally, our work provides crucial insights into understanding the charge storage process of zinc-ion hybrid supercapacitors and designing hybrid supercapacitors with new material chemistries.

Advanced Electrode Materials Comprising of Structure‐Engineered Quantum Dots for High‐Performance Asymmetric Micro‐Supercapacitors

AbstractMicro‐supercapacitors (MSCs) as a new class of energy storage devices have attracted great attention due to their unique merits. However, the narrow operating voltage, slow frequency response, and relatively low energy density of MSCs are still insufficient. Therefore, an effective strategy to improve their electrochemical performance by innovating upon the design from various aspects remains a huge challenge. Here, surface and structural engineering by downsizing to quantum dot scale, doping heteroatoms, creating more structural defects, and introducing rich functional groups to two dimensional (2D) materials is employed to tailor their physicochemical properties. The resulting nitrogen‐doped graphene quantum dots (N‐GQDs) and molybdenum disulfide quantum dots (MoS2‐QDs) show outstanding electrochemical performance as negative and positive electrode materials, respectively. Importantly, the obtained N‐GQDs//MoS2‐QDs asymmetric MSCs device exhibits a large operating voltage up to 1.5 V (far exceeding that of most reported MSCs), an ultrafast frequency response (with a short time constant of 0.087 ms), a high energy density of 0.55 mWh cm−3, and long‐term cycling stability. This work not only provides a novel concept for the design of MSCs with enhanced performance but also may have broad application in other energy storage and conversion devices based on QDs materials.

Environmental Gating and Galvanic Effects in Single Crystals of Organic-Inorganic Halide Perovskites.

Understanding the impact of environmental gaseous on the surface of organometal halide perovskites (OMHPs) couples to the electronic and ionic transport is critically important. Here, we explore the transport behavior and origins of the gas sensitivity in MAPbBr3 single crystals (SCs) devices using impedance spectroscopy and current relaxation measurements. Strong resistive response occurs when crystals are exposed to different environments. It was shown that SC response to the environment is extremely different at the surface as compared to the bulk due to the disorder surface chemistry. The nonlinear transport properties studied using ultrafast Kelvin probe force microscopy (G-KPFM) to unravel spatio-temporal charge dynamics at SC/electrode interface. The relaxation processes observed in pulse relaxation and G-KPFM measurements along with gas sensitivity of crystals suggest the presence of a triple-phase boundary between environment, electrode, and crystal. Results indicate that the environment is a nontrivial component in the operation of OMHP devices which is reminiscent of fuel cell systems. Furthermore, the triple-phase boundary can play a significant role in the transport properties of OMHPs due to the possibility of the redox processes coupled to the concentration of bulk ionic species. Although instrumental for understanding the device characteristics of perovskites, our studies suggest a new opportunity of coupling the redox chemistry of the Br2-Br- pair that defines the bulk ionic conductivity of MAPbBr3 with the redox chemistry of gaseous (or liquid) environment via a suitable electrocatalytic system to enable new class of energy storage devices and gas sensors.

Hetero-Atom Doped Highly Conductive Porous Carbon for Exceptional Electrochemical Performance

In response to the growing global energy needs, the dependency on fossil fuels can lead to the harsh effects on the environment. Thus, it is crucial to recognize continuously growing energy demand by expanding the energy conversion and storage technologies, which exploit clean and renewable energy resources. In this concern, the progress of new energy conversion and storage devices are detected as one of the most important topics in clean energy applications. To efficiently use the produced energy in automobiles, portable applications, it must be stored absolutely so that it can be reproduced when required. Supercapacitors are new class of energy storage devices, in which carbon nanomaterials with controlled porous structure and unique physicochemical properties are among the crucial components. Supercapacitors have the benefit of rapid recharge ability, greater stability, and long cycle life. However, further enhancement of the electrochemical performance, particularly improving the energy density, is a quite challenging. To deal this difficulty, several approaches such as the utilization of carbon materials with high active surface area and studies in various non-aqueous electrolytes also have been attempted. Further, electrochemically energetic materials such as conducting polymers have been developed to enhance the specific capacitance. But they found limited practical applications due to the deterioration of the rate capability and cycle stability. Hetero-atom doping is another productive approach to modify the properties of the carbon nanomaterials and their electrochemical performance. Conductive polymers specifically, polypyrrole is ideal precursor for preparation of hetero-atom doped carbon nanomaterials. However, there is a demand to develop highly conductive porous carbon nanomaterials with high active surface area and hetero-atom doping using a simple method. Here, we present a simple yet productive method for synthesizing hetero-atom doped highly conductive porous carbon with high specific surface area and unique hierarchical pore structure. We prepared the large-scale synthesis of nitrogen-doped porous carbon wrapped reduced graphene oxide-partially exfoliated carbon nanotubes (NP-(rGO-PECNT)) with interconnected hierarchical porous structure. Here, the polypyrrole conductive polymer acts as both nitrogen and carbon source, thereby contributing to pseudocapacitance while, rGO-PECNT conductive matrix provides a high specific surface area for ion and charge transportation. The derived porous (NP-(rGO-PECNT)) displays 7 at % nitrogen content with a specific surface area 2400 m2 g-1, and pore volume 1.81 cm3 g-1. The fabricated supercapacitor using (NP-(rGO-PECNT)) as an electrode material exhibits excellent specific capacitance of 800 F g-1 at 2 A g-1, with high cycling stability of 96 % over 10000 cycles.

All Solid State Supercapacitors Based on Ionic Liquid/Crosslinked PEO-PPO Tetrablock Copolymer Electrolytes

Supercapacitors are widely recognized as an important class of energy storage devices, because they can provide a high specific power, long cycle life. Compared with the conventional supercapacitors using liquid electrolyte, all-solid state supercapacitors have many advantages such as lightweight, high flexibility, high safety and environmentally benign nature, which are suitable for flexible and portable electronics. The realization of high performance all solid state supercapacitors strongly depends on the electrical properties and mechanical integrity of constitutive materials and their controlled assembly of electrode and solid electrolyte. In this work, we designed and prepared novel ionic liquid (IL)-doped crosslinked PEO-PPO tetrablock copolymer electrolytes. Triethoxysilane-endcapped precursors were first prepared by reacting the terminal hydroxyl groups of the corresponding Tetronic® (BASF) copolymers with 3-isocyanatopropyl triethoxysilane. Then, the IL-doped and crosslinked electrolytes were fabricated via in situ sol-gel reactions of the triethoxysilane end groups of the precursors and subsequent solution casting process in the presence of IL. Despite large IL doping up to 200 wt%, solid and transparent film could be obtained mainly due to the crosslinked structure. The resulting electrolytes were denoted as cTPL-TPE-A-B, where A and B indicate the codename of Tetronic® and the content of IL doped, respectively. It was confirmed that cTPL-TPE-A-Bs possessed completely amorphous structure and non-fusible property from the XRD and DSC experiments. The Ionic conductivity of a cTPL-TPE-90R4-200 with 200 wt% BMIM-BF4 reached 3.65×10-3 S/cm at room temperature and 2.73×10-2 S/cm at 80 °C (see Figure 1). These values were more than 10 times higher than those of the PEO electrolyte with the same range of BMIM-BF4 content thanks to the entirely amorphous structure of cTPL-TPE-A-Bs. All-solid-state supercapacitors were fabricated assembling cTPL-TPE-A-Bs as electrolytes with graphene sheets (prepared from a kneading method) as electrodes. Consequently, the device exhibited high electrochemical performance such as high operating voltage of 3.7 V, high specific capacitance of 157.4 F/g, and an energy density of 55.3 Wh/kg (@ 10 mA/g). Figure 1

Effect of Anodic Deposition Parameters on Electrochemical Behavior and Microstructure of Mn-Ni Oxide As a Pseudocapacitive Electrode

Hybrid supercapacitors, or briefly pseudocapacitors, are an emerging class of energy storage devices, with the capability of providing both high power and energy density. In contrast to conventional electric double layer capacitors, which accumulate charge mostly through an electrostatic mechanism, pseudocapacitors utilize the pseudocapacitance arising from reversible Faradic reactions occurring at the electrode surface [1]. Although various metal oxides have been investigated as active material for pseudocapacitors, greater attention has been given to manganese oxides. In recent years, also Mn-based binary oxides have been studied for pseudocapacitance, in particular, mixed oxides comprising Ni or Co as the other component [2-4] In the present work, Mn-Ni oxide thin films were deposited potentiodynamically at scan rate of 100 mVs-1, pH=7 and room temperature, on a stainless steel substrate. Undoubtedly, a survey of the literature shows that a systematic study on the effect of operating parameters on the properties of the mixed oxide thin films is still lacking. Accordingly, this work was undertaken with the aim of exploring the processing space for these oxides studying in particular the effects of the electrolyte Ni to Mn molar ratio, the deposition peak potential and the deposited mass on chemical composition, microstructure and capacitance behavior of Mn-Ni oxide thin films. The binary oxide deposits were characterized by energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). The electrochemical behavior of the Mn-Ni oxide electrodes was studied by cyclic voltammetry (CV) at 5, 20, 50 and 100 mVs-1 and electrochemical impedance spectroscopy (EIS) in 1 M Na2SO4electrolyte. Expectedly, with increasing the Ni to Mn molar ratio in solution (from 0.1 to 10), the molar fraction of Ni in the oxide film was found to increase, resulting, on the one hand, in smoothing of the surface morphology and, on the other hand, in a change of the specific capacitance through a maximum of 145 Fg-1 at approximately 12% at Ni fraction and CV scan rate of 20 mVs-1. With further increase of the Ni fraction in the oxide to about 19% at, the specific capacitance started to decrease gradually. Changing the peak potential in the potentiodynamic deposition from +1.2 to +1.6 V vs. Ag/AgCl, the CV curves revealed a box-like shape for all values of the peak potential, while the capacitance showed a decreasing trend. EIS results revealed that charge transfer resistance increased with increasing peak potential and the lowest Rct was found for sample prepared at peak potential of 1.2 V vs. Ag/AgCl. The mass load per unit area of the film was controlled by the number of cycles. Finally, specific capacitance of 196 Fg-1 was obtained at scan rate of 5 mVs-1 for the Mn-Ni oxide film deposited potentiodynamically (5 cycles, 100 mVs-1, pH=7 and RT) in solution with Ni to Mn molar ratio of 2. At the high scan rate of 100 mVs-1, the specific capacitance was 135 Fg-1 showing good retention of the capacitance at high rate.

Asymmetric electrochemical capacitors—Stretching the limits of aqueous electrolytes

Abstract