Materials For Electrochemical Energy Storage Research Articles

Cu1.5Mn1.5O4 hollow sphere decorated Ti3C2Tx MXene for flexible all-solid-state supercapacitor and electromagnetic wave absorber

Flexible energy storage systems and electromagnetic pollution have become issues that need to be resolved in equipment research and development due to the widespread use of portable electronic devices and 5G networks. MXene is competent for supercapacitors and electromagnetic wave absorbers through sensible composite and microstructure design. Herein, Cu1.5Mn1.5O4 Hollow Nanosphere Decorated Ti3C2Tx MXene (CuMnHS@MX) was prepared by simple electrostatic self-assembly. Hybrid membranes can be quickly prepared by vacuum-assisted filtration. CuMnHS@MX exhibits excellent electromagnetic wave absorption performance and electrochemical energy storage properties. High specific capacitance (2089 mF/cm2 at 2.5 mA/cm2) and excellent cycle stability (99.89% after 8000 cycles) are achieved, which are attributed to the increased interlayer spacing and improved interlayer ion transport efficiency. When assembled into symmetrical flexible all-solid-state supercapacitor (SC), the device has a specific capacitance of 382.9 mF/cm2 and an energy density of 53.18 μWh/cm2 at a power density of 277.8 μW/cm2. Meanwhile, CuMnHS@MX has advantageous absorbing properties. When the thickness is 4 mm, the minimum reflection loss (RLmin) is −53.42 dB at 6.08 GHz. Adjustable absorbing property is achieved, and the absorbing energy efficiency can cover X and most C, Ku bands. These excellent EMA properties are derived from the 3D structure and rich dipole/interface polarization. CuMnHS@MX is a promising bifunctional material for electrochemical energy storage and electromagnetic wave absorption.

The HER performance of 2D materials is underestimated without morphology correction

2D transition metal dichalcogenides (2D-TMDs) are considered promising materials for electrochemical catalysis and energy storage. However, large differences in electrochemical performance have been reported for 2D-TMD electrodes with different morphology, such as thickness, edge density, and porosity. We here demonstrate that limitations in the homogeneous charge transfer of 2D-TMDs are responsible for the significant observed variations in hydrogen evolution reactions (HER). Statistical electrochemical characterization was conducted on microscopic MoS2 and WS2 devices with compositional uniformity and controllable morphology by localized HER measurements. Detailed analysis establishes the dominating effect of the uncompensated resistance on overpotential and Tafel slope, which are commonly utilized as HER figures of merit. A correction scheme is presented that reveals the intrinsic electrocatalytic properties of 2D materials electrodes, independent of morphology. This approach was applied to previously reported polarization data and revealed differences between extracted and intrinsic Tafel slopes of up to 400% leading to potentially erroneous assignments of the HER mechanism. Finally, the correlation of two-terminal carrier transport measurements and electrochemical characterization demonstrates the in-plane conduction as the origin of the low electrochemical activity in 2D-TMDs. Our results highlight the impact of morphology-dependent carrier transport on the electrochemical properties of 2D materials.

Reduced graphene oxides prepared via explosive and non-explosive thermal reduction: Structural evolution, functional properties and reinforcing efficacy

The present study reveals the influences of heating rate, as employed during thermal reduction of graphene oxide (GO) to reduced graphene oxide (rGO), on the degree of exfoliation and defect structure of the resulting rGO, and, in turn, the effects of the same on the physical properties, electronic properties, performances as electrode material for electrochemical energy storage and efficacy as mechanical reinforcement in brittle materials. Faster heating (@ 10 °C/min) of GO to 350 °C has been found to result in efficient thermal exfoliation, yielding rGO (R10) with ∼400% increase in specific surface area, but with a highly disordered structure. By contrast, slower heating (@ 1 °C/min; as for R01) causes reduction in surface area by ∼30% (w.r.t. GO) due to failure of exfoliation. However, both the rGOs exhibit high defect density (viz., distance between defect sites; Ld ∼1.12–1.3 nm), corresponding to stage 2 of disorder (as per analysis based on Raman spectra). Higher sp2 C fraction in R01 results in higher electronic conductivity, whereas significantly larger specific surface area, along with relatively lower crystallite size and Ld, bestows R10 with higher capacity and rate-capability in the context of electrochemical Li-/Na-storage. As reinforcement in alumino-borosilicate glass-ceramic, while GO and R10 have been found to improve the resistances towards crack propagation and abrasive wear damage (w.r.t. unreinforced alumino-borosilicate), incorporation of R01 deteriorates both these aspects primarily due to inefficient exfoliation of R01, concomitant poor dispersion, failure of reinforcing mechanisms and presence of thicker flakes acting as sites of excessive material damage.

Hierarchical porous carbon nanoarchitectonics with honeycomb-like and N, P co-doped features for flexible symmetric supercapacitors and high-efficiency dye removal

In this study, we prepared a variety of hierarchical porous carbon (NPy-HPC) nanoarchitectonics with honeycomb-like and nitrogen‑phosphorus co-doping features utilizing a combination of self-doping and external doping ways to maximally improve the properties of biomass-derived porous carbon. The as-obtained NP1.0-HPC possesses an appropriate heteroatom content (3.15 at.% for nitrogen and 0.3 at.% for phosphorous), high specific surface area of 2141 m2 g−1 and total pore volume of 1.04 cm3 g−1, making it a potentially bifunctional material for electrochemical energy storage and dye removal applications. The free-standing NP1.0-HPC electrode exhibits excellent electrochemical performance with a high specific capacitance of 378.8 F g−1 at 1 A g−1 and a good rate capability of 271.6 F g−1 when increasing the current density to 20 A g−1. The NP1.0-HPC//NP1.0-HPC symmetrical supercapacitor as well displays a desirable energy density of 17.7 Wh kg−1 at a power density of 440 W kg−1. Besides, NP1.0-HPC shows well removal capability for various kinds of dyes, among which the cationic dye methylene blue and the anionic dye methyl orange with the uptake of 666.9 and 360.9 mg g−1, respectively. Our work proposes a facile and cost-effective strategy for the exploration and development of superior performance controllable three-dimensional (3D) laminated porous carbon nanoarchitectonics.

Biocarbon Derived from Seeds of Palmyra Palm Tree for a Supercapacitor Application

Carbon-based materials are among the most promising materials for future electrochemical energy storage and conversion. Eco-friendly Palmyra palm seed derived microporous biocarbon was fabricated on the graphitic sheet. Palm seed derived carbon was carbonized by using 0.5 M H2S04 without any activating agent. Morphological characterization of PSDC investigated through SEM (Scanning Electron Microscopy). It shows PSDC is microporous with carbon network like structure. Physiochemical characterization performed through XRD, FT-IR and Raman studies. Raman studies confirm the PSDC having carbon based material. Electrochemical performance by using Cyclic voltammetry (CV), Galvanostatic charge discharge (GCD) and Electrochemical Impedance spectroscopy (EIS). PSDC exhibits the specific capacitance of 220 F/g at 5 A and 276.5 F/g at 1 A current as well as remarkable capacitance retention after 500 cycles is 63.1%. It shows PSDC having remarkable electrochemical storage application.

Research on integrated micro-energy storage technology based on multi-type electrochemistry

Electrochemical energy storage is a process that utilizes chemical reactions to store and release electrical energy in the form of chemical energy. These include lead-acid, lithium-ion, flow, sodium-sulfur batteries, etc., while electrochemical energy storage materials and technologies are the keys to solving the utilization, conversion, and storage of clean energy. In order to solve the problem that the current energy storage technology has an extensive range of energy storage frequency fluctuations in the application process, this paper conducts research on a comprehensive micro-energy storage technology based on multi-type electrochemistry, which improves the stability of energy storage. Based on the introduction of multi-type electrochemical technology, MXene (Ti3C2) was selected as the dispersion liquid, and PVA was used as the gel electrolyte to complete both preparations. The device’s fabrication and assembly are completed based on calculating the rated power, rated capacity, and other parameters of the micro energy storage capacitor. Aiming at the ultra-low frequency oscillation problem that may exist in the energy storage process, this paper develops a micro energy storage control method that participates in primary frequency modulation. The comparison experiment proves that the frequency fluctuation of the new energy storage technology is within the controllable range in practical application, which can effectively improve the stability of energy storage.

Special Section on 2D Materials for Electrochemical Energy Storage and Conversion

Electrochemical energy storage and conversion are currently one of the most critical challenges due to the increasing energy demand. Therefore, discovering novel materials to develop low-cost and more efficient energy storage technologies is urgently necessary. Among various novel materials, two-dimensional (2D) materials have attracted intensive research activities in multiple fields due to their fascinating physical and chemical properties. The 2D materials having a higher surface-to-volume ratio are beneficial to developing low-cost and large-scale energy storage systems for practical applications. There have been many promising concepts of 2D material-based real-life energy applications recently in batteries, supercapacitors, fuel cells, solar cells, thermoelectric, triboelectric generators, etc. Despite recent progress, significant efforts are still needed to investigate the fundamentals of 2D materials for electrochemical energy storage and conversion. Over the past few years, there has been substantial progress in modeling, theories, and experimental characterizations of 2D materials for energy storage and conversion. This timely Special Section issue addressed some recent advances in this critical area. We have selected eight papers covering a gamut of electrochemical-centric research in 2D materials for energy storage and conversion.In this issue, Qu et al. reported the electrochemical evaluation of helical carbon nanofibers (HCNFs) prepared by the ethanol flame method as anode materials of lithium-ion batteries. Their results show that HCNFs possess high reversible capacity, good rate performance, and excellent cycling stability. Farma et al. investigated a simple and cost-effective method to generate porous carbon activation from Palmae plant waste biomass, namely, areca leaf midrib (ALM). They showed that the electrochemical properties of activated carbon supercapacitor cells derived from ALM biomass have the highest specific capacitance value and scan rate in a two-electrode system. Arumugam et al. discussed a ternary composite made up of graphene oxide, polyaniline, and zinc oxide as an electrode material for supercapacitors with its structural and electrochemical properties. The ternary composite exhibited the highest specific capacitance. Metzger et al. focused on using graphene-coated proton exchange membrane (PEM) to reduce fuel crossover. They found that the adhesion of graphene on PEMs is insufficient for prolonging fuel cell operation, resulting in graphene delamination at high temperatures and higher fuel crossover values compared to lower temperature testing. Zaidi et al. reported the superior performance of graphene nanosheet (GNS) materials over Vulcan XC incorporated as a cathode catalyst in Li-O2 battery. The GNS catalysts demonstrated promising performance at higher current densities and with various organic electrolytes. Pandey et al. synthesized a mechanically stable, proton-conducting, and very cost-effective nanocomposite membrane using a simple and scalable phase-inversion approach. The synthesized proton-conducting nanocomposite membrane was demonstrated as a potential advanced functional solid electrolyte for possible application in proton exchange membrane fuel cells. Fauzi et al. reported the thermophysical properties of N,N-diethylethanolammonium chloride/ethylene glycol-DES (deep eutectic solvent) for the replacement of ionic liquid. They studied the physical properties of DES, which are thermal conductivity, viscosity, and surface tension. Finally, the review article by Zeng et al. provided an overview of the application of conductive diamond in electrocatalytic reduction and outlined the improvement of electrochemical properties by employing metal particles to modify the surface.We believe that this Special Section issue will be a valuable contribution to the energy storage and conversion literature and open new frontiers for researchers. The interdisciplinary field of 2D material-based energy storage is rapidly evolving. Our Special Section issue will motivate many researchers to implement novel techniques, such as artificial intelligence, digital twins, and automated advanced manufacturing, in this field and initiate new collaborations between experimentalists, theorists, and modelers. We would like to thank all contributors to this Special Section issue for submitting their latest high-impact work. Also, special thanks would go out to the invited reviewers for helping us further enhance the quality of the articles.

Partial Oxidation to Extend the Lifetime of Nanoporous Carbon in an Ultracapacitor with Li2SO4 Electrolyte

A TiC-derived carbon (CDC) and its partially oxidized derivative (ox-red-CDC), oxidized by a modified Hummers method, were studied as promising electrode materials for electrochemical energy storage. To evaluate the electrochemical properties of the carbon materials, cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy measurements were performed in 1 M Li2SO4 using 2- and 3-electrode cells. A partially oxidized surface was shown to improve the capacitance and electrochemical stability of a nanoporous CDC at positive potential values. The respective anodic capacitance of 80 F cm-3 reveals a 15% improvement over the non-oxidized CDC. At negative potential values, the capacitance of two carbon materials is almost equal, 97 vs. 93 F cm-3, for the non-oxidized and partially oxidized CDC materials, respectively. An asymmetric 2-electrode ultracapacitor containing ox-red-CDC as the anode and pristine CDC as the cathode demonstrated an excellent cycle life. The temporary repolarization of the 2-electrode cell after thousands of charge-discharge cycles increased the capacitance and improved the cycling characteristics, likely due to regeneration and cleaning of the electrode surface.

Editorial: Interface and structure designs of electrode materials for advanced electrochemical energy storage

The increasing demand for mobile power supplies in electric vehicles has motivated intense research 18 efforts in developing high-performance electrochemical energy storage (EES) devices. However, 19 current EES technologies have not met the requirements for various applications to improve 20 performance and safety, and reduce cost and environmental footprint. Advanced materials, including 21 active anode and cathode materials, inactive carbon and binding additives, metal current collectors, 22 separators, and electrolytes, play the essential role in supporting battery operations. Particularly, the 23 interface engineering of distinct phases or components in composite electrodes and electrolytes, as well 24 as the hierarchical structure design for each component or multi-component device, can address many 25 fundamental issues associated with the charge transport kinetics, electrochemical characteristics, and 26 chemical/physical/mechanical properties. Therefore, it is possible to improve the energy storage 27 performance, reliability, and safety by investigating the interface and structure. 28

Metal-Organic Framework Composites and Their Derivatives as Efficient Electrodes for Energy Storage Applications: Recent Progress and Future Perspectives.

Metal-organic frameworks (MOFs) have been important electrochemical energy storage (EES) materials because of their rich species, large specific surface area, high porosity and rich active sites. Nevertheless, the poor conductivity, low mechanical and electrochemical stability of pristine MOFs have hindered their further applications. Although single component MOF derivatives have higher conductivity, self-aggregation often occurs during preparation. Composite design can overcome the shortcomings of MOFs and derivatives and create synergistic effects, resulting in improved electrochemical properties for EES. In this review, recent applications of MOF composites and derivatives as electrodes in different types of batteries and supercapacitors are critically discussed. The advantages, challenges, and future perspectives of MOF composites and derivatives have been given. This review may guide the development of high-performance MOF composites and derivatives in the field of EES.

A High-Entropy Oxide as High-Activity Electrocatalyst for Water Oxidation.

High-entropy materials are an emerging pathway in the development of high-activity (electro)catalysts because of the inherent tunability and coexistence of multiple potential active sites, which may lead to earth-abundant catalyst materials for energy-efficient electrochemical energy storage. In this report, we identify how the multication composition in high-entropy perovskite oxides (HEO) contributes to high catalytic activity for the oxygen evolution reaction (OER), i.e., the key kinetically limiting half-reaction in several electrochemical energy conversion technologies, including green hydrogen generation. We compare the activity of the (001) facet of LaCr0.2Mn0.2Fe0.2Co0.2Ni0.2O3-δ with the parent compounds (single B-site in the ABO3 perovskite). While the single B-site perovskites roughly follow the expected volcano-type activity trends, the HEO clearly outperforms all of its parent compounds with 17 to 680 times higher currents at a fixed overpotential. As all samples were grown as an epitaxial layer, our results indicate an intrinsic composition-function relationship, avoiding the effects of complex geometries or unknown surface composition. In-depth X-ray photoemission studies reveal a synergistic effect of simultaneous oxidation and reduction of different transition metal cations during the adsorption of reaction intermediates. The surprisingly high OER activity demonstrates that HEOs are a highly attractive, earth-abundant material class for high-activity OER electrocatalysts, possibly allowing the activity to be fine-tuned beyond the scaling limits of mono- or bimetallic oxides.

Enhanced energy storage performance of the three-dimensional nickel nitride mesh with mesoporous structure derived from nickel hydroxide nanowires for advanced hybrid supercapacitors

Nickel nitrides are considered to be promising for hybrid supercapacitors (HSCs) as electrochemical energy storage materials, owing to their good electrical conductivity. However, nickel nitride is prone to agglomeration in high-temperature preparation process, resulting in lower specific surface area and higher porosity, further inhibiting its energy storage performance in HSCs. Consequently, a three-dimensional Ni3N mesh with a mesoporous structure (3D Ni3N Mesh) was constructed as the electrode material for HSCs via a facile hydrothermal reaction and nitrogenization treatment in this work. The as-prepared 3D Ni3N Mesh was built from Ni3N nanoparticles as the bricks that employed the nickel hydroxide nanowires as the precursors. The electrochemical tests demonstrated that the specific capacity of the as-prepared 3D Ni3N mesh could reach 254.2 mAh g−1 at 1 A g−1 in the three-electrode cell. The specific capacity of the 3D Ni3N mesh is still up to 108.3 mAh g−1, even at a high current density of 30 A g−1. The changes of the micro-nano structure, chemical composition and energy storage mechanism of the 3D Ni3N mesh electrode materials in the charge-discharge process were also analyzed and discussed. To further demonstrate its potential applications, a HSCs was also assembled with the 3D Ni3N mesh and the activated carbon (AC) as the positive and negative electrode respectively. It is worth mentioning that the specific capacity of the 3D Ni3N mesh//AC HSCs is 59.3 mAh g−1 at 0.5 A g−1, while the energy density also reaches 56.2 Wh kg−1 at a power density of 468 W kg−1. In addition, the 3D Ni3N Mesh//AC HSCs still maintains 77.4 % capacity along with an average coulombic efficiency of 98.7 % after 5000 continuous cycles, demonstrating good cyclic reversibility.

Research Progress of Cathode Materials for Rechargeable Aluminum Batteries in AlCl3/[EMIm]Cl and Other Electrolyte Systems

AbstractThe development of safe, cheap, and environmentally friendly advanced rechargeable batteries with high energy density are one of the most pressing tasks for today‘s energy crisis. With the advantages of low cost, abundant reserves, and high‐level safety, rechargeable aluminum ion batteries are considered ideal candidates for next‐generation energy storage batteries in the context of large‐scale energy applications. Relevant knowledge of energy storage materials and electrolytes, which possess close connection in between, is undeniably crucial for such research, while ironically, most attention is attracted to merely one element alone, especially the energy storage materials involving micro/nanomaterials. In this review, we focus on cathode materials matching with various electrolyte systems for rechargeable aluminum batteries and manage to provide new ideas for the preparation methods of high‐efficiency electrochemical energy storage materials, with future outlooks in this field.

On the rising extra storage capacity of ultra-small Fe[formula omitted]O[formula omitted] particles functionalized with HCS and their potential as high-performance anode material for electrochemical energy storage

We report a nanocomposite material exhibiting ultra-small Fe3O4 nanoparticles uniformly decorated on hollow carbon spheres (Fe3O4@HCS). The unique hierarchically-structured material displays excellent electrochemical cycling performance that exceeds the theoretical bulk capacity of Fe3O4 when used as an anode in lithium-ion batteries. In particular, it features increasing reversible capacity upon cycling yielding 1050 mAh g−1at 0.1 A g−1 in cycle 250. Comprehensive scanning and transmission electron microscopy images combined with detailed electrochemical analysis demonstrate that the outstanding electrochemical performance can be traced back to the formation and decomposition of a capacitative surface layer during dis/charging.

Hydrogen-bonded organic frameworks and their derived materials for electrochemical energy storage and conversion

Hydrogen-bonded organic frameworks and their derived materials for electrochemical energy storage and conversion

Amorphous Electrode: From Synthesis to Electrochemical Energy Storage

Electrochemical batteries and supercapacitors are considered ideal rechargeable technologies for next‐generation energy storage systems. The key to further commercial applications of electrochemical energy storage devices is the design and investigation of electrode materials with high energy density and significant cycling stability. Recently, amorphous materials have attracted a lot of attention due to their more defects and structure flexibility, opening up a new way for electrochemical energy storage. In this perspective, we summarize the recent research regarding amorphous materials for electrochemical energy storage. This review covers the advantages and features of amorphous materials, the synthesis strategies to prepare amorphous materials, as well as the application and modification of amorphous electrodes in energy storage fields. Finally, the challenges and prospective remarks for future development in amorphous materials for electrochemical energy storage are concluded.

Molten salt electrosynthesis of Cr2GeC nanoparticles as anode materials for lithium-ion batteries.

The two-dimensional MAX phases with compositional diversity are promising functional materials for electrochemical energy storage. Herein, we report the facile preparation of the Cr2GeC MAX phase from oxides/C precursors by the molten salt electrolysis method at a moderate temperature of 700°C. The electrosynthesis mechanism has been systematically investigated, and the results show that the synthesis of the Cr2GeC MAX phase involves electro-separation and in situ alloying processes. The as-prepared Cr2GeC MAX phase with a typical layered structure shows the uniform morphology of nanoparticles. As a proof of concept, Cr2GeC nanoparticles are investigated as anode materials for lithium-ion batteries, which deliver a good capacity of 177.4mAhg-1 at 0.2 C and excellent cycling performance. The lithium-storage mechanism of the Cr2GeC MAX phase has been discussed based on density functional theory (DFT) calculations. This study may provide important support and complement to the tailored electrosynthesis of MAX phases toward high-performance energy storage applications.

Highly Cross-Linked 3D ε-Fe2O3 Networks Organized by Ultrathin Nanosheets as High-Performance Anode Materials for Lithium-Ion Storage

The rational design and engineering of three-dimensional (3D) micro-/nano-architectures still remains a technological challenge for electrochemical energy storage materials. In the current work, a facile and scalable structural engineering strategy is described for the synthesis of highly cross-linked 3D ε-Fe2O3 networks via an in situ manipulation of the molecular framework-engaged reactions. The as-obtained ε-Fe2O3 with a large specific surface area and abundant mesopores possesses a 3D interlocked architecture organized by ultrathin nanosheets. The formation mechanism of this unique structure is explored, which is shown to be Fe(CN)64–-mediated molecular-level template action leading to the self-assembly of a 3D framework. As a conversion-type anode for LIBs, the optimized ε-Fe2O3 networks exhibit a high reversible specific capacity, good rate capability, as well as long-term stability, with a reversible capacity of 953.8 mAh g–1 that is retained beyond 600 cycles at 1.0 A g–1. In addition, the excellent Li storage performance can be ascribed to the microarchitectured ε-Fe2O3 networks, which provide multiscale dimensions, mesoporous structure, some oxygen deficiencies, as well as good structural integrity upon prolonged cycling. Furthermore, the experimental results and DFT calculations showed that ε-Fe2O3 was able to form a key Li5Fe5O8–x phase during the lithiation/delithiation process, in which the structural properties of ε-Fe2O3 inherently favor the intercalation of Li+ ions within ε-Fe2O3, thus leading to the experimentally observed high performance rates.

LiFePO4@C/graphene composite and in situ prepared NaFePO4@C/graphene composite as high-performance cathode materials for electrochemical energy storage

LiFePO4@C/graphene composite and in situ prepared NaFePO4@C/graphene composite as high-performance cathode materials for electrochemical energy storage

Acid-Base Chemistry Provides a Simple and Cost-Effective Route to New Redox-Active Ionic Liquids.

Redox-active ionic liquids (RAILs) hold great promise as high density electrochemical energy storage materials, but are hampered by high costs and low bulk conductivities. In this work, we introduce and electrochemically characterise novel redox-active protic ionic liquids (RAPILs) formed by acid-base neutralisation from cheap and plentiful starting materials. We also demonstrate a novel RAIL-in-IL solvent system for electrochemical characterisation of RAPILs, which enables efficient and cost-effective determination of redox potentials and screening for electrochemical reversibility. Of the redox-active ionic liquids tested in this work, only propylammonium 4-nitrophenylacetate demonstrates completely reversible electrochemistry and preservation of ionic character upon redox cycling under acidic or neutral conditions. Propylammonium 2,5-dihydroxyphenyl-carboxylate also demonstrates two reversible redox processes, but is unstable to oxidation at 0.27 V vs Ag (-0.14 V vs Fc), most likely forming an uncharged benzoquinone species. Using the lessons learned from this prototypical set of RAPILs, we propose design criteria to guide future experimental and computational work.