Electrochemical Energy Storage Performance Research Articles

Defect-free potassium manganese hexacyanoferrate cathode material for high-performance potassium-ion batteries

Potassium-ion batteries (KIBs) are promising electrochemical energy storage systems because of their low cost and high energy density. However, practical exploitation of KIBs is hampered by the lack of high-performance cathode materials. Here we report a potassium manganese hexacyanoferrate (K2Mn[Fe(CN)6]) material, with a negligible content of defects and water, for efficient high-voltage K-ion storage. When tested in combination with a K metal anode, the K2Mn[Fe(CN)6]-based electrode enables a cell specific energy of 609.7 Wh kg−1 and 80% capacity retention after 7800 cycles. Moreover, a K-ion full-cell consisting of graphite and K2Mn[Fe(CN)6] as anode and cathode active materials, respectively, demonstrates a specific energy of 331.5 Wh kg−1, remarkable rate capability, and negligible capacity decay for 300 cycles. The remarkable electrochemical energy storage performances of the K2Mn[Fe(CN)6] material are attributed to its stable frameworks that benefit from the defect-free structure.

Cu-Fe based oxides and selenides as advanced electrode materials for high performance symmetric supercapacitors

Copper-based chalcogenides are becoming popular as electrode materials for electrochemical energy storage. Herein, we report the electrochemical energy storage performance of CuFeO2 and CuFeSe2 synthesized via facile solvothermal method. At 1 A g−1, the symmetric supercapacitors based on CuFeO2 electrodes and CuFeSe2 electrodes exhibit specific capacitance values of 128 F g−1 and 260 F g−1, respectively. Further, CuFeO2 and CuFeSe2 electrodes demonstrate incredible specific energy values of 18 Wh kg−1 and 36 Wh kg−1, respectively, at a specific power of 1 kW kg−1. Moreover, both CuFeO2 and CuFeSe2 electroactive materials result in enhanced capacitive retention of 96% and 97%, respectively, for 10,000 charge-discharge cycles. The remarkable electrochemical energy storage performance of both CuFeO2 and CuFeSe2 materials make them potential aspirants for future energy storage systems.

Structural and stability analysis of Na4Mn4Ti5O18 for energy storage application

We report a single-phase Na4Mn4Ti5O18 oxide prepared via ceramic processing route. Rietveld refinement of X-ray diffraction results indicated orthorhombic unit cell indexed with Pbam space group. Further, structural analysis using X-ray diffraction, transmission electron microscopy and Raman spectroscopy suggested crystal structure comprising two distinct tunnel pathway, polygonal and Z-shaped tunnels with void dimensions ~ 4.07 A and ~ 3.01 A, respectively, suitable for reversible cation transport desirable for energy storage applications. X-ray photoelectron spectroscopy confirmed presence of Mn2+, Mn3+, Mn4+ and Ti4+ in Na4Mn4Ti5O18. Surface morphology in field emission scanning electron microscopy exhibited inhomogenously distributed micro-bead grains separated by well-defined boundaries in good agreement with complex impedance spectrum results. Estimated dc conductivity and surface area is ~ 1.745 × 10− 6 S cm− 1 and ~ 0.66 m2g− 1 respectively. Electrochemical energy storage performance with cell; Na || 1 M NaFSI (EC : DMC, 1:1 v/v%) || Na4Mn4Ti5O18 in voltage range 2.0–3.8 V indicated reversible redox action. Identical cell in voltage range 0.01–2.5 V, exhibited pseudo-capacitive behaviour. Results suggest energy storage possibility with Na4Mn4Ti5O18 electrode.

Three‐dimensional printing of high‐mass loading electrodes for energy storage applications

AbstractNanostructured materials afford a promising potential for many energy storage applications because of their extraordinary electrochemical properties. However, the remarkable electrochemical energy storage performance could only be harvested at a relatively low mass‐loading via the traditional electrode fabrication process, and the scale of these materials into commercial‐level mass‐loading remains a daunting challenge because the ion diffusion kinetics deteriorates rapidly along with the increased thickness of the electrodes. Very recently, three‐dimensional (3D) printing, a promising additive manufacturing technology, has been considered as an emerging method to address the aforementioned issues where the 3D printed electrodes could possess elaborately regulated architectures and rationally organized porosity. As a result, the outstanding electrochemical performance has been widely observed in energy storage devices made of 3D printed electrodes of high‐mass loading. In this review, we systemically introduce the basic working principles of various 3D printing technologies and their practical applications to manufacture high‐mass loading electrodes for energy storage devices. Challenges and perspectives in 3D printing technologies for the construction of electrodes at the current stage are also outlined, aiming to offer some useful opinions for further development for this prosperous field.image

Oxygen vacancies enriched nickel cobalt based nanoflower cathodes: Mechanism and application of the enhanced energy storage

The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo2O4 (NCO-Air) and CoNiO2 (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m2/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.

2D MXene Materials for Sodium Ion Batteries: A review on Energy Storage

The performance of electrochemical energy storage (EES) devices highly rely on the in-built properties of the material. Due to the excellent properties of 2D materials, a much of research has been conducted on 2D materials. In the past decade, a novel family of 2D carbides and nitrides materials have been successfully prepared called MXene using stripping method, from layered precursors. The accessibility of solid solutions, the control of surface terminals and the latest innovation of MXene layers provide potential for the preparation of several new structures. Multifunctional chemistry of MXene allows adjustments to the performance in the field of energy storage. In addition, some distinctive EES properties have been revealed. With the advancement in EES field, it is necessary to understand the application of MXene in the EES field in time. This review primarily emphasis the synthesis, structure and energy storage application of MXene are introduced. More importantly, the theoretical and experimental electrochemical performances are compared and criticized. Finally, the future research scope and outlook of MXene in the field of energy storage systems is prospected.

Kilogram-Scale Synthesis and Functionalization of Carbon Dots for Superior Electrochemical Potassium Storage.

Carbon dot is a type of carbon material with an ultrasmall size of less than 10 nm for all three dimensions, which has attracted more and more attention due to its useful merits. Unfortunately, the complicated synthesis method and low yield largely limit its wide large-scale application. Herein, an inexpensive and high-efficiency aldol condensation method under ambient temperature and pressure was proposed for the large-scale synthesis of CDs, which can obtain products with 1.083 kg in 2 h and realize the functionalization of carbon dots doped with nitrogen (NCDs) and sulfur/nitrogen doubly (NSCDs), and then the mechanism and structure of CDs formation were explained. Moreover, utilizing the feature of controllable assembly of carbon dots, and combined with theoretical calculations, we have designed functionalized 1D carbon fibers (CF) to construct high-performance potassium storage anode materials through the assembly of carbon dots induced by a Zn compound. Benefitting from the microstructure and surface functional groups derived from CDs, the N-doped CF (NCF700) exhibits superior electrochemical energy storage performance for potassium ion batteries (PIBs). This study provides a low-cost and high-yield method to produce CDs and promotes the practical application of CDs in electrochemical energy storage.

Pan‐Milling: Instituting an All‐Solid‐State Technique for Mechanical Metastable Oxides as High‐Performance Lithium‐Ion Battery Anodes

AbstractAll‐solid‐state mechanochemistry is experiencing an exciting period of renaissance, thanks in part to the recent discovery of its ability to realize chemical synthesis that is inaccessible to solution‐based methods. Among them, high‐energy ball‐milling is widely used in large‐scale preparation of metal oxide composites for lithium‐ion batteries (LIBs). However, ball‐milling‐induced high‐energy mechanical activation may destroy crystalline structure, and thus the electrochemical activity of many metastable oxides such as anatase titanium dioxide (TiO2). Herein, the mechanism that anatase TiO2 undergoes the crystalline‐amorphous phase transformation subject to ball‐milling is reported and a new pan‐milling mechanochemical technique for preparation of stable anatase TiO2/graphene (TiO2/GNS) composites is demonstrated. The pan‐milling technique not only preserves the original crystal structure of TiO2 but also realizes a good dispersion of TiO2 nanoparticles on graphene nanosheets through its unique 3D shear force. When used as anode for LIBs, the pan‐milled TiO2/GNS demonstrates high reversible specific capacity, excellent rate capability, and long cycle stability, in comparison to the ball‐milled TiO2/GNS that shows no capacity. By tapping into the huge potential of pan‐milling mechanochemistry, this work opens the door to large‐scale all‐solid‐state preparation of mechanical metastable oxides with desired electrochemical performance for energy storage.

Surface selenium doped hollow heterostructure/defects Co-Fe sulfide nanoboxes for enhancing oxygen evolution reaction and supercapacitors

The strategy of constructing a three-dimensional hierarchically porous architecture with heterointerface and defects to rich the electrochemically active site, and rapid electron transfer has been considered as an effective strategy to achieve the excellent electrochemical performance in electrochemical energy storage and conversion. Herein, a Se-doped hollow heterostructure/defects Co-Fe sulfide (Se-(CoFe)S2) box has been developed via a facile sulfurization-selenization treatment of hollow Co-Fe Prussian blue analogues precursor. Remarkably, the abundant hierarchical macro-mesopores of hollow Se-(CoFe)S2 nanobox with excellent structural stability and unique electrical properties can not only effectively expose the electrochemically accessible active sites but also significantly improve the electrolyte transport and electron transfer, thus boosting electrochemical performances in oxygen evolution reaction (OER) and supercapacitors in alkaline media. For OER, the Se-(CoFe)S2 electrocatalyst shows a small overpotential of 281 mV at 10 mA cm−2 and a low Tafel slope of 51.8 mV dec−1 as well as high stability. Furthermore, it also shows good performance for supercapacitors, suggesting its great potential as an efficient electrode for sustainable energy applications. Superb properties highlight the great prospects of PBA-based derivatives in applications of energy storage and conversion.

Effects of reduction method on reduced graphene oxide and its electrochemical energy storage performance

To enhance the application of reduced graphene oxide (rGO) in energy storage field, the effects of reduction method on rGO and its electrochemical energy storage performance were researched in this paper. Green and environmentally friendly reduction methods, such as l-ascorbic acid method (LAA), hydrothermal method and sodium borohydride method (NaBH4), were used to reduce the GO obtained by Hummers' method to rGO. The obtained samples were analyzed and characterized by Fourier transform Infrared spectroscopy, Ultraviolet-visible spectroscopy, X-ray diffraction, scanning electron microscope, Raman spectroscopy and N2 absorption and desorption. The obtained rGO samples were being assembled into symmetrical electrochemical super-capacitors with using organic solution as the electrolyte to characterize their electrochemical energy storage performance including cyclic voltammetry, galvanostatic charge and discharge, AC impedance and cycle life tests. The research results showed that the GO could all be changed into rGO via the reduction methods mentioned above, but the reduction degree and morphology structure of the obtained rGOs were quite different: the rGO obtained by LAA had a very smooth surface; the surface of rGO obtained by hydrothermal reduction method had wrinkles and formed a layered cross-linked structure; while the rGO obtained by NaBH4 showed severe agglomeration, forming obvious blocks. The electrochemical test results showed that the rGO obtained by hydrothermal reduction had the best electrochemical performance among the samples: its specific capacitance could reach 140 F g−1 (organic electrolyte) at a current density of 1 A g−1, moreover it had an energy density of 43.75 Wh kg−1 and a power density of 4500 W kg−1.

Recent Progress in Binder‐Free Electrodes Synthesis for Electrochemical Energy Storage Application

AbstractFabrication of binder‐free electrodes is an effective way to increase the performance of electrochemical energy storage (EES) devices, such as rechargeable batteries and supercapacitors. In traditional electrodes, the binder is usually electrochemically inert and has weak interactions and interfaces between binder and the active material, which increase “dead mass” and directly affect the performance of energy storage system. The binder‐free electrode can provide well‐designed electrode material structure enables well connection between active materials themselves and current collectors. In addition, without insulating binder, electron and electrolyte ions can transfer more efficiently within the electrode materials. Here, we reviewed research efforts in using various techniques involving chemical, physical and electrical methods to fabricate binder‐free electrodes. For every technique, we first briefly describe their principle and involved factors that influence the performance of as‐fabricated binder‐free electrodes and summarize advantages and disadvantages. Next, we reviewed several works which have used this technique to fabricate binder‐free electrodes. Further, the effect of well‐crafted structure design on the properties of energy storage performances including rate capability, and cycle stability was highlighted. Last, we offer our perspectives on the challenges and potential future research directions in this area. We hope this review can stimulate more research to design and synthesize the binder‐free materials for EES devices.

Plasma-assisted lattice oxygen vacancies engineering recipe for high-performing supercapacitors in a model of birnessite-MnO2

Defect engineering has been considered as an efficient strategy to enhance the electrochemical performance of transition metal oxides based energy storage devices. However, the electrochemical activity and stability were greatly determined by the defect located crystal and external environments, which dominate the electrochemical properties of its based electrode. Thus, regulating a defect engineering recipe becomes a vital and direct route to advance the performance of the electrode materials. Herein, a versatile recipe combining the mild H-plasma and O-plasma was demonstrated for prototypical birnessite-MnO2 to achieve the robust lattice oxygen vacancies in birnessite-MnO2 (LOV-MnO2), targeting to boost its electrochemical energy storage performance. Theoretical calculation reveals the facilitated ion intercalation and diffusion kinetics due to the lower energy barrier in the LOV-MnO2. The LOV-MnO2 demonstrates an exceptional electrochemical performance with a specific capacitance as high as 445.1 F g−1 (at the current density of 1 A g−1), and the diffusion-controlled capacitance contribution reaches unprecedented ~70% (at a scan rate of 5 mV s−1). Besides, the configured symmetrical supercapacitor device LOV-MnO2//LOV-MnO2 delivers remarkable performance with an energy density of 92.3 Wh kg−1 at a power density of 1100.3 W kg−1 with a widen working voltage of 2.2 V. An outstanding cyclic life of 92.2% capacitance retention was also achieved after 10,000 charge–discharge cycles. Such superior electrochemical performance suggests that the proposed defect engineering recipes here will aid in the future development of advanced electrode materials for electrochemical energy storage devices.

Highly Ordered TiO2 Nanotube Arrays with Engineered Electrochemical Energy Storage Performances.

Nanoscale engineering of regular structured materials is immensely demanded in various scientific areas. In this work, vertically oriented TiO2 nanotube arrays were grown by self-organizing electrochemical anodization. The effects of different fluoride ion concentrations (0.2 and 0.5 wt% NH4F) and different anodization times (2, 5, 10 and 20 h) on the morphology of nanotubes were systematically studied in an organic electrolyte (glycol). The growth mechanisms of amorphous and anatase TiO2 nanotubes were also studied. Under optimized conditions, we obtained TiO2 nanotubes with tube diameters of 70–160 nm and tube lengths of 6.5–45 μm. Serving as free-standing and binder-free electrodes, the kinetic, capacity, and stability performances of TiO2 nanotubes were tested as lithium-ion battery anodes. This work provides a facile strategy for constructing self-organized materials with optimized functionalities for applications.

Synthesis of Two-Dimensional Sr-Doped LaNiO3 Nanosheets with Improved Electrochemical Performance for Energy Storage.

Designing a novel, efficient, and cost-effective nanostructure with the advantage of robust morphology and outstanding conductivity is highly promising for the electrode materials of high-performance electrochemical storage device. In this paper, a series of honeycombed perovskite-type Sr-doped LaNiO3 nanosheets with abundant porous structure were successfully synthesized by accurately controlling the Sr-doped content. The study showed that the optimal LSNO-0.4 (La0.6Sr0.4NiO3-δ) electrode exhibited excellent electrochemical performance, which showed a high capacity of 115.88 mAh g−1 at 0.6 A g−1. Furthermore, a hybrid supercapacitor device (LSNO//AC) based on LSNO-0.4 composites and activated carbon (AC) showed a high energy density of 17.94 W h kg−1, a high power density of 1600 W kg−1, and an outstanding long-term stability with 104.4% capacity retention after 16,000 cycles, showing an excellent electrochemical performance and a promising application as an electrode for energy storage.

An enhanced electrochemical energy storage performance based on porous activated carbon and hard carbon derived from natural maple leaf

The recent development of the nanostructured electrode materials with a large porous carbon structure assures the next-generation material for the high-energy storage application. Herein, we report hard carbon (HC), and activated carbon (AC) materials from natural maple leaf derived. A facilely synthesized zinc chlorate presence and non-presence maple leaf were prepared for the pyrolysis temperature of 800 °C under the nitrogen atmosphere. Various analytical techniques investigated the as-prepared HC and AC samples. The HC and AC modified electrode performances were analyzed using cyclic voltammetry (CV) and galvanostatic charge/discharge in the presence of 6.0 M KOH electrolyte. The most efficient AC and HC performance derived from maple leaves shows the specific capacitance values of 217 F g−1 and 118 F g−1, respectively. The AC-modified electrode showed a promising candidate for high energy storage performance for a practical application.

Hierarchical Ni-Co-Mn hydroxide hollow architectures as high-performance electrodes for electrochemical energy storage.

In this study, hierarchical Ni–Co–Mn hydroxide hollow architectures were successfully achieved via an etching process. We first performed the synthesis of NiCoMn-glycerate solid spheres via a solvothermal route, and then NiCoMn-glycerate as the template was etched to convert into hierarchical Ni–Co–Mn hydroxide hollow architectures in the mixed solvents of water and 1-methyl-2-pyrrolidone. Hollow architectures and high surface area enabled Ni–Co–Mn hydroxide to manifest a specific capacitance of 1626 F g−1 at 3.0 A g−1, and it remained as large as 1380 F g−1 even at 3.0 A g−1. The Ni–Co–Mn hydroxide electrodes also displayed notable cycle performance with a decline of 1.6% over 5000 cycles at 12 A g−1. Moreover, an asymmetric supercapacitor assembled with this electrode exhibited an energy density of 44.4 W h kg−1 at 1650 W kg−1 and 28.5 W h kg−1 at 12 374 W kg−1. These attractive results demonstrate that hierarchical Ni–Co–Mn hydroxide hollow architectures have broad application prospects in supercapacitors.

Recent progress in conductive polymers for advanced fiber-shaped electrochemical energy storage devices

Conductive polymers endow fiber-shaped electrodes and devices with excellent mechanical and electrochemical performance for energy storage in future wearable electronics.

High-performance ultracapacitor electrodes realized by 3-dimensionally bicontinuous block copolymer nanostructures with enhanced ion kinetics

Exceptional electrochemical energy-storage performances are demonstrated with three-dimensionally bicontinuous carbon nanostructures with interconnected, size-tunable macro-channels derived from block copolymer self-assembly.

Coffee-derived activated carbon from second biowaste for supercapacitor applications

The electrochemical energy storage performance of activated carbons (ACs) obtained from coffee-derived biowastes was assessed. ACs were obtained from spent coffee ground second waste, after polyphenol extraction, by means of a hydrothermal process followed by physical or chemical activation. The resulting materials exhibited microporous structures with a total specific area between 585 and 2330 m2·g−1. Scanning electron microscopy (SEM) revealed a highly porous microstructure in the case of the chemically activated carbons, while physical activation led to a cracked micro-sized morphology. The electrochemical properties of the materials for supercapacitor applications were investigated in 1 M Na2SO4. After chemical activation, the coffee-derived material displayed a capacitance of 84 F·g−1 at 1 A·g−1 in a 1.9 V voltage window, with 70% capacitance retention at 10 A·g−1 and 85% retention after 5000 cycles of continuous charge-discharge. This work demonstrates how coffee secondary biowaste can be conveniently activated to perform as electrochemical energy storage material, contributing to its revalorization and reinsertion in a circular economy.

High performance Li-ion hybrid capacitors with micro-sized Nb14W3O44 as anode

Niobium tungsten oxides (Nb-W-O) have been verified as promising Li storage anodes because of their similar working voltage and cycling stability to Li4Ti5O12 but higher specific capacity than the latter. However, the phase and microstructural evolutions of a designated Nb-W-O compound during sintering as well as its possible application in Li-ion hybrid capacitors have not been reported. In this work, micro-sized phase pure Nb14W3O44 is obtained by sintering a solvothermal-derived precursor at about 1050 °C, which as a Li-ion insertion host exhibits not only high reversible specific capacity up to 226 mAh g−1 at 0.04 A g−1, but outstanding rate capability (137 mAh g−1 at 6 A g−1) and cycle stability (74.2% capacity retention at 2 A g−1 after 1000 cycles). Such an excellent rate capability enables the Nb14W3O4 anode highly matchable to the capacitive cathode and yields high energy densities of 64.6 and 29.2 Wh kg−1 at 198.9 and 14,576 W kg−1, respectively, in Li-ion hybrid capacitors, along with a high capacity retention of 83.9% after 3,000 cycles at 1 A g−1. With these excellent electrochemical energy storage performances and a high packing density, the micro-sized Nb14W3O44 can be a very promising anode material for both Li-ion batteries and Li-ion hybrid capacitors towards high energy-power outputs.