Emerging Electrode Materials Research Articles

3D Ternary Hybrid of VSe2/e‐MXene/CNT with a Promising Energy Storage Performance for High Performance Asymmetric Supercapacitor

AbstractMXene and TMDs are two of the emerging electrode materials for supercapacitors owing to their unique physicochemical properties such as high conductivity, large surface area, and rich redox active sites. However, sheet restacking, volume expansion and oxidation hinder these materials from being used in practical applications. In this work, a 3D ternary hybrid structure of metallic VSe2, Ti3C2Tx MXene and carbon nanotube was designed to address some of the challenges in 2D materials‐based electrodes for supercapacitor application. The exfoliated MXene and CNT decorated VSe2 3D structure showed excellent synergy between each component to deliver promising energy storage and cycling performance. The ternary hybrid structure also can suppress the surface oxidation of MXene sheets during the hydrothermal reaction. Furthermore, an asymmetric supercapacitor fabricated with VSe2/e‐MXene/CNT and MoS2/MXene delivered the highest energy density of 35.91 Wh/kg at a power density of 1280 W/kg and a remarkable cycle life.

Electrochemical performance of V2O5/TiO2 nanocomposite: As an emerging electrode material for supercapacitor application

This scrutiny encounters the hydrothermal approach of binary nanocomposites V2O5/TiO2 (VT). The XRD pattern substantiated the formation of the binary composites with 18 nm of the crystallite size without any extraneous impurities. Whereas, HR-SEM implies the efficient bonding and homogeneous distribution between V2O5 and TiO2 nanoparticles, which provokes high electrochemical performances. Additionally, the BET analysis exposes the specific surface area to be 251 m2 g−1 with an average pore size of 3.14 nm for the VT nanocomposite. The electrochemical performances of the binary VT nanocomposite exhibit high specific capacitance of 443.7 Fg−1 at a current density of 1 Ag−1 with an excellent cyclic retention of 90 % even after successive 5000 cycles at 5 Ag−1. Therefore, the results obtained in this study clearly demonstrates that the binary nanocomposite VT would be a favorable electrode material for the commercial energy storage applications.

Zn doping induces rich oxygen vacancies in δ-MnO2 flower-like nanostructures for impressive energy density coin cell supercapacitor

In this work, Zn-doped δ-MnO2 (ZnMO) flower-like nanostructures on carbon fibers are synthesized by one-pot hydrothermal method. It is found that insertion of Zn ions induces oxygen vacancy defects, increase in active sites and conductivity of δ-MnO2 (MO) structure. These features making ZnMO structure an excellent candidate for the fabrication of electrode material for supercapacitors. It has been revealed that ZnMO@CC electrode delivered an enhanced specific capacitance of 667 F g−1 at a current density of 1 A g−1 as compared to the pristine δ-MnO2 and previously reported nanostructures. The developed asymmetric coin cell supercapacitor (ZnMO//AC) obtained a specific capacitance of 116 F g−1 at 1 A g−1 and achieved an outstanding energy density of 71.5 Wh kg−1 at a power density of 1067.1 W kg−1. Moreover, the device retains its initial capacitance of 92 % after 8000 cycles at 8 A g−1. These results suggest that ZnMO could be an emerging electrode material for the fabrication of high-performance supercapacitors for practical applications. This research hunts for new visions for the preparation of MnO2-based material by doping strategy for energy storage applications, especially supercapacitor.

Battery-like supercapacitor electrodes utilizing porous hierarchical bush-like ZnO/SnS on nickel foam framework

This paper reports the electrochemical activity of mesoporous bush like ZnO/SnS nanocomposites, with a specific capacity of 523.60 C g−1, at a current density of 1 A g−1, which is higher than the specific capacities offered by pristine SnS (301.15 C g−1) and ZnO (32.67 C g−1) electrodes. The ZnO/SnS composite electrode exhibits a greater energy density of ~36.36 Wh kg−1with a power density of 250 W kg−1. The composite electrode has a cyclic stability with 56 % capacity retention for over 3500 cycles. The enhanced electrochemical performance of ZnO/SnS composite structure is attributed to its bush like morphology with a large surface area (204.4 m2 g−1) which provides a greater number of electro-active sites for the absorption of ions that leads to efficient charge transportation pathways. This type of morphology is attained only when the orthorhombic SnS nanoflakes are grown over hexagonal ZnO nanoparticles, by surfactant free homogenous precipitation method. These results demonstrate that ZnO/SnS composite is an emerging electrode material for supercapacitor application.

A sustainable bio-based char as emerging electrode material for energy storage applications

In the last few years, extensive research efforts have been made to develop novel bio-char-based electrodes using different strategies starting from a variety of biomass precursors as well as applying different thermochemical conversion paths. In this regard, hydrothermal carbonization method is becoming a more prevalent option among conversion procedures even if pyrolysis remains crucial in converting biomass into carbonaceous materials. The main aim of this study is to develop an innovative supercapacitor electrode from spruce bark waste through a unique low-temperature technique approach, which proved to effectively eliminate the pyrolysis step. Consequently, a hybrid spruce-bark-graphene oxide compound (HySB) was obtained as electrode material for supercapacitors. When compared to a regularly used commercial electrode material, SLC1512P graphite (reference) with 150.3 µF cm−2 capacitance, the HySB has a substantially higher capacitive performance of 530.5 µF cm−2. In contrast to the reference, the HySB polarization resistance increases by two orders of magnitude at the stationary potential and by three orders of magnitude at the optimum potential, underlying that the superior performances of HySB extend beyond static conditions. The synthesis strategy provides an appropriate energy-efficient option for converting biomass into carbonaceous materials with meaningful properties suitable for energy storage applications.

Renewable biopolymer-derived carbon–nickel oxide nanocomposite as an emerging electrode material for energy storage applications

The high capacity electrode material design with rapid charging/discharging and long life capability have become critical issue and main concern in recent years. Nickel oxide (NiO) has received much attention in the field of energy storage as a cathode electrode materials owing to its layered structure with large spacing, crystal structure, and high specific surface area. In this study the chitosan derived carbon–nickel oxide ([email protected]) nanocomposite was synthesized from a NiO nanoparticle precursor using a precipitation approach, and chitosan (a renewable biopolymer) was used as a carbon resource. The formation mechanism, structural behavior, and morphological properties were examined using various types of microscopic and spectroscopic characterization techniques. The design material tested further as electrode material in an electrochemical half-cell and full cell symmetric assembly. In three electrode system the [email protected] nanocomposite exhibited satisfactory electrochemical performance with a high specific capacitance around 1011.10 Fg-1 and better cyclic stability 94.20% after 3000 cycles. In two electrode symmetric supercapacitive system the fabricated [email protected] delivered maximum Cs 88.30 Fg-1, stability with higher power density 7.84 Whkg-1 at energy density of 133.05 Wkg-1. The fabricated [email protected] electrode material retain the cyclic stability around 90% after 3500 consecutive charge/discharge cycles.

A Cost-Effective, Nanoporous, High-Entropy Oxide Electrode for Electrocatalytic Water Splitting

High-entropy materials have attracted extensive attention as emerging electrode materials in various energy applications due to their flexible tunability, unusual outstanding activities, and cost-effectiveness using multiple earth-abundant elements. We introduce a novel high-entropy composite oxide with the five elements of Cu, Ni, Co, Fe, and Cr (HEO-3CNF) for use in the oxygen evolution reaction (OER) in electrocatalytic water splitting. HEO-3CNF is composed of two phases with a non-equimolar, deficient high-entropy spinel oxide of (Cu0.2−xNi0.2Co0.2Fe0.2Cr0.2)3O4 and monoclinic copper oxide (CuO). Electrochemical impedance spectroscopy (EIS) with distribution of relaxation times (DRT) analysis validates that the HEO-3CNF-based electrode exhibits faster charge transfer than benchmark CuO. It results in improved OER performance with a lower overpotential at 10 mA/cm2 and a Tafel slope than CuO (518.1 mV and 119.7 mV/dec versus 615.9 mV and 131.7 mV/dec, respectively) in alkaline conditions. This work may provide a general strategy for preparing novel, cost-effective, high-entropy electrodes for water splitting.

Interface Engineering of Nickel Selenide and Graphene Nanocomposite for Hybrid Supercapacitor

Nickel selenide is an emerging electrode material for high‐performance hybrid supercapacitors; however, poor electrical conductivity and sluggish ion kinetics limit its application. Herein, a unique architecture by decorating NiSe nanoparticles on reduced graphene oxides (rGO) is developed. The synergistic effect of NiSe and rGO facilitated by the optimized addition of rGO results in significant improvement in the electrochemical performance. The physicochemical characterizations suggest that the enhancement can be attributed to increased interfacial interaction and access to the electrochemically active sites. The NiSe/rGO hybrid delivers a specific capacity of 351 mAh g−1 at 1 A g−1, which is significantly higher than that for bare NiSe. Later, the hybrid supercapacitor based on NiSe/rGO hybrid as positive and activated carbon as negative electrode delivers a maximum energy density of 49.6 Wh kg−1 at a power density of 748.37 W kg−1. In addition, the device shows good cyclic stability of 83.3% over 5000 cycles. Thus, an innovative approach to the development of high‐performance hybrid supercapacitors is offered.

Polyoxometalates (POMs) with Ion/Electron‐Sponge Properties and Abundant Active Sites as Emerging Electrode Materials for Secondary Batteries: A Review

AbstractFaced with the increasingly severe energy and environment issues, eco‐friendly and efficient energy storage/transformation technology has become a research hotspot. Due to the ion/electron‐sponge properties and superior catalytic performance, polyoxometalates (POMs) have broad prospects in improving the performance of electrodes and batteries. In this paper, the structural characteristics and physical/chemical properties of POMs are introduced, and the recent research progresses of POM‐electrodes for various battery systems are reviewed. By analyzing the relationship between the composition, structure and electrochemical performance of POMs, the advantages and challenges of applying POMs as electrode materials are explained, and the practical modification strategies for improving the performance of POM‐electrode are proposed, aiming to provide reference for the further investigation and application of POMs in energy storage field.

Efficient Reformulation of Linear and Nonlinear Solid-Phase Diffusion in Lithium-ion Battery Models using Symmetric Polynomials: Mass Conservation and Computational Efficiency

Lithium-ion batteries are typically modeled using porous electrode theory coupled with various transport and reaction mechanisms, along with suitable discretization or approximations for the solid-phase diffusion equation. The solid-phase diffusion equation represents the main computational burden for typical pseudo-2-dimensional (p2D) models since these equations in the pseudo r-dimension must be solved at each point in the computational grid. This substantially increases the complexity of the model as well as the computational time. Traditional approaches towards simplifying solid-phase diffusion possess certain significant limitations, especially in modeling emerging electrode materials which involve phase changes and variable diffusivities. A computationally efficient representation for solid-phase diffusion is discussed in this paper based on symmetric polynomials using Orthogonal Collocation and Galerkin formulation (weak form). A systematic approach is provided to increase the accuracy of the approximation (p form in finite element methods) to enable efficient simulation with a minimal number of semi-discretized equations, ensuring mass conservation even for non-linear diffusion problems involving variable diffusivities. These methods are then demonstrated by incorporation into the full p2D model, illustrating their advantages in simulating high C-rates and short-time dynamic operation of Lithium-ion batteries.

Highly Crystalline Polyimide Covalent Organic Framework as Dual-Active-Center Cathode for High-Performance Lithium-Ion Batteries

Polyimide covalent organic framework (PI-COF) materials that can realize intrinsic redox reactions by changing the charge state of their electroactive sites are considered as emerging electrode materials for rechargeable devices. However, the highly crystalline PI-COFs with hierarchical porosity are less reported due to the rapid reaction between monomers and the poor reversibility of the polyimidization reaction. Here, we developed a water-assistant synthetic strategy to adjust the reaction rate of polyimidization, and PI-COF (COFTPDA-PMDA) with kgm topology consisting of dual active centers of N,N,N',N'-tetrakis(4-aminophenyl)-1,4-benzenediamine (TPDA) and pyromellitic dianhydride (PMDA) ligands was successfully synthesized with high crystallinity and porosity. The COFTPDA-PMDA possesses hierarchical micro-/mesoporous channels with the largest surface area (2669 m2/g) in PI-COFs, which can promote the Li+ ions and bulky bis(trifluoromethanesulfonyl)imide (TFSI-) ions in organic electrolyte to sufficiently interact with the dual active sites on COF skeleton to increase the specific capacity of cathode materials. As a cathode material for lithium-ion batteries, COFTPDA-PMDA@50%CNT which integrated high surface area and dual active center of COFTPDA-PMDA with carbon nanotubes via π-π interactions gave a high initial charge capacity of 233 mAh/g (0.5 A/g) and maintains at 80 mAh/g even at a high current density of 5.0 A/g after 1800 cycles.

Improved electrochemical performance for alkali and alkaline metal doped nanostructures as electrode material for energy storage applications

Bismuth phosphate is one of the emerging electrode materials for various energy storage applications. Here we analyzed the electrochemical behavior of pure as well as alkali and alkaline metal (Na, K, and Mg) doped bismuth phosphate nanostructures synthesized using the microwave method. The phase and crystal structure of all the synthesized samples was confirmed through XRD. FESEM and High-resolution transmission electron spectroscopy (HRTEM) confirm the morphology and planes of prepared samples. Various oxidation states of the best-performed material were analyzed through X-ray photoelectron spectroscopy (XPS). Different doping elements play a significant role in tuning the electrochemical property of working electrodes for supercappetry/energy storage applications. All the pure and alkali doped working electrodes exhibited the high potential window of 1.4 V in an aqueous electrolyte which is an important parameter to enhance the energy density for the device applications. The specific capacity calculated from GCD is found to be maximum for Na-doped bismuth phosphate nanostructures, i.e., 1020 Cg−1 at the current density of 2 Ag−1. The cycle stability test was performed for the Na-doped bismuth phosphate sample for 3000 cycles with 86 % retention.

Multiscale Polymeric Materials for Advanced Lithium Battery Applications.

Riding on the rapid growth in electric vehicles and the stationary energy storage market, high-energy-density lithium-ion batteries and next-generation rechargeable batteries (i.e., advanced batteries) have been long-accepted as essential building blocks for future technology reaching the specific energy density of 400Wh kg-1 at the cell-level. Such progress, mainly driven by the emerging electrode materials or electrolytes, necessitates the development of polymeric materials with advanced functionalities in the battery to address new challenges. Therefore, it is urgently required to understand the basic chemistry and essential research directions in polymeric materials and establish a library for the polymeric materials that enables the development of advanced batteries. Herein, based on indispensable polymeric materials in advanced high-energy-density lithium-ion, lithium-sulfur, lithium-metal, and dual-ion battery chemistry, the key research directions of polymeric materials for achieving high-energy-density and safety are summarized and design strategies for further improving performance are examined. Furthermore, the challenges of polymeric materials for advanced battery technologies are discussed.

Improved electrochemical performance of rare earth doped Bi1−xMxPO4 (x = 0, 0.15; M = La, Ce, Sm) Nanostructures as electrode material for energy storage applications

Bismuth phosphate is one of the emerging electrode materials for various energy storage applications. Here we analyzed the electrochemical behavior of doped bismuth phosphate nanostructures with La, Ce, and Sm synthesized using a hydrothermal route. The electrochemical performance of these rare earth-doped bismuth phosphate nanostructures has never been reported earlier. The structural and morphological analysis confirms the hexagonal and monoclinic phases. High–resolution X-ray photoelectron spectroscopy (XPS) spectra confirm the oxidation states of the synthesized samples. Various doping elements play a significant role in tuning the electrochemical property of working electrodes for super cappetry/energy storage applications. All the pure and doped working electrodes exhibited the high potential window of 1.4 V in an aqueous electrolyte which is an important parameter to enhance the energy density for the device applications. The specific capacity is found to be maximum for Sm-doped bismuth phosphate nanostructures, i.e., 1135 Cg−1at the current density of 1 Ag−1. The cycle stability test was performed for the Sm-doped bismuth phosphate sample for 4000 cycles with 92 % retention. The results analysis revealed that Sm doped bismuth phosphate nanostructures as a electrode material has great potential for practical utility in energy storage applications.

Fabrication of robust Fe2O3@NiCo2O4 core-shell composite with spikey surface for high-performance asymmetric solid-state supercapacitor

The need for a cost-effective and efficient energy storage system instigates researchers to develop emerging electrode materials for energy storage devices. The α-Fe2O3-based electrode material for supercapacitor application has received interest due to its good electrochemical performance, high mechanical strength, corrosion resistance, low cost, and abundant availability. This work develops a cost-effective, robust Fe2O3@NiCo2O4 core-shell composite with spikey surface via a facile hydrothermal strategy for high-performance electrode material for supercapacitors. The spikes of Fe2O3 are developed on NiCo2O4 to collaborate in a more accessible surface area, with robust morphological stability throughout electrochemical performances. The Fe2O3@NiCo2O4 core-shell composite exhibits a high specific capacity of 364 C g−1 at the scan rate of 5 mV s−1 and 81% cycling stability up to 10,000 successive charge-discharge cycles at the current density of 15 A g−1. Moreover, an asymmetric solid-state supercapacitor (ASSC) device was fabricated using Fe2O3@NiCo2O4 composite as a positive electrode and commercially purchased activated carbon as a negative electrode assembled via PVA/KOH gel electrolyte. The fabricated device offers a significant energy density of 31.7 W h Kg−1 at a power density of 700 W Kg−1. The ASSC exhibits excellent capacitance retention of 90% with ultra-high coulombic efficiency of 99.7% up to 10,000 GCD cycles. The ASSC can illuminate the red and yellow LED light. This work indicates that a robust Fe2O3@NiCo2O4 core-shell composite can be an economic strategy for fabricating high-performance practical supercapacitor applications.

Recent Progress of Electrode Architecture for MXene/MoS2 Supercapacitor: Preparation Methods and Characterizations.

Since their discovery, MXenes have conferred various intriguing features because of their distinctive structures. Focus has been placed on using MXenes in electrochemical energy storage including a supercapacitor showing significant and promising development. However, like other 2D materials, MXene layers unavoidably experience stacking agglomeration because of its great van der Waals forces, which causes a significant loss of electrochemically active sites. With the help of MoS2, a better MXene-based electrodecan is planned to fabricate supercapacitors with the remarkable electrochemical performance. The synthesis of MXene/MoS2 and the ground effects of supercapacitors are currently being analysed by many researchers internationally. The performance of commercial supercapacitors might be improved via electrode architecture. This analysis will support the design of MXene and MoS2 hybrid electrodes for highly effective supercapacitors. Improved electrode capacitance, voltage window and energy density are discussed in this literature study. With a focus on the most recent electrochemical performance of both MXene and MoS2-based electrodes and devices, this review summarises recent developments in materials synthesis and its characterisation. It also helps to identify the difficulties and fresh possibilities MXenes MoS2 and its hybrid heterostructure in this developing field of energy storage. Future choices for constructing supercapacitors will benefit from this review. This review examines the newest developments in MXene/MoS2 supercapacitors, primarily focusing on compiling literature from 2017 through 2022. This review also presents an overview of the design (structures), recent developments, and challenges of the emerging electrode materials, with thoughts on how well such materials function electrochemically in supercapacitors.

Application of deep learning for informatics aided design of electrode materials in metal-ion batteries

To develop emerging electrode materials and improve the performances of batteries, the machine learning techniques can provide insights to discover, design and develop battery new materials in high-throughput way. In this paper, two deep learning models are developed and trained with two feature groups extracted from the Materials Project datasets to predict the battery electrochemical performances including average voltage, specific capacity and specific energy. The deep learning models are trained with the multilayer perceptron as the core. The Bayesian optimization and Monte Carlo methods are applied to improve the prediction accuracy of models. Based on 10 types of ion batteries, the correlation coefficients are maintained above 0.9 compared to DFT calculation results and the mean absolute error of the prediction results for voltages of two models can reach 0.41 V and 0.20 V, respectively. The electrochemical performance prediction times for the two trained models on thousands of batteries are only 72.9 ms and 75.7 ms. Besides, the two deep learning models are applied to approach the screening of emerging electrode materials for sodium-ion and potassium-ion batteries. This work can contribute to a high-throughput computational method to accelerate the rational and fast materials discovery and design.

Rational material design of Li-excess metal oxides with disordered rock salt structure

This review article summarizes recent research development on a new class of electrode materials with a cation-disordered rock salt structure for energy storage applications. Historically, oxide-based electrode materials with the disordered rock salt structure are regarded as “electrochemically inactive.” However, recent experimental and theoretical research reveals that many oxides with the disordered rock salt structure can be utilized as high-capacity electrode materials, which deliver a much larger reversible capacity compared with traditional and cation ordered layered materials used for practical battery applications. For these emerging electrode materials, higher energy density is achieved relying on anionic and/or cationic redox as multi-electron reactions. Moreover, this anionic/cationic redox for Li-excess materials with the rock salt structure is effectively activated for nano-sized materials. These new trends for the material design on high-capacity electrode materials are highlighted and the future direction to design Li/Na insertion materials for energy storage applications is outlooked.

Graphene decorated LiMn2O4 electrode material for hybrid type energy storage devices

AbstractLithium‐ion capacitors (LICs) are becoming useful owing to their high energy and power densities. LICs show enhance capacitance than electric double‐layer capacitance (EDLC) and pseudocapacitors, due to their battery electrode material, which can operate over a higher voltage window. LiMn2O4 is fast emerging electrode material for energy storage devices. The major limitation associated with it is the low conductivity. Therefore, to simultaneously improve the electrical conductivity as well as the electrochemical performance, a novel strategy of decoration LiMn2O4 with graphene is being proposed. Graphene will improve electrical conductivity while contributing to EDLC and pseudocapacitance values. A cost‐effective synthesis protocol is utilized to obtain conical pyramid‐type particles. These particles were thoroughly characterized using a large number of experimental techniques. Cyclic voltammetry and charge‐discharge measurements were used to evaluate the electrochemical characteristics, in 0.0 to 1.2 V stable window, using 1M LiOH electrolyte. Graphene decorated LiMn2O4 electrode show improved cyclic stability and higher specific capacitances 250 F/g in comparison to LiMn2O4 electrode. The cycling stability of the electrode was above 90% up to 3000 cycles at a higher current density.

Recent advances in solid‐state supercapacitors: From emerging materials to advanced applications

Solid-state supercapacitors (SSCs) hold great promise for next-generation energy storage applications, particularly portable and wearable electronics, implementable medical devices, the Internet of Things (IoT), and smart textiles. This review is intended to present the broad picture of SSC technology by covering various kinds of all-solid-state and flexible solid-state supercapacitors. The review begins with introducing a brief history of the development of supercapacitors and then discusses the fundamentals, charge storage mechanisms, and the performance evaluation methods of SSCs. The next chapter provides an overview of the solid-state electrolytes, notably solid polymer electrolytes, inorganic electrolytes, and redox-active solid electrolytes. In this study, a particular focus is given to the electrode fabrication methods and some emerging electrode materials, such as covalent organic frameworks (COFs), metal-organic frameworks (MOFs), metal nitrides (MNs), MXenes, polyoxometalates (POMs), and black phosphorus (BP). Subsequently, the performance of SSCs with different configurations based on the cell design (ie, symmetric, asymmetric) and the electrode type (ie, freestanding, fiber, interdigitated, flexible) is discussed. This review also presents a comprehensive summary of the latest innovations and state-of-the-art applications of SSCs, including electrochromic, self-healing, shape memory, thermally chargeable, piezoelectric-, photo-SSCs. The final section highlights the future directions and critical technological challenges in the field of SSCs.