Electrodes For Electrochemical Energy Storage Research Articles

Insights from the Physicochemical and Electrochemical Screening of the Potentiality of the Chemically Synthesized Polyaniline

Polyaniline (PANI) is a candidate for electrocatalysis, and can be combined with metal nanoparticles to fabricate high-performance electrodes for electrochemical energy conversion and storage. However, its intrinsic properties appear to be dependent on the synthesis conditions so that from the majority of the reports, it is quite difficult to establish an overall performance trend. In this contribution, we report an extensive and systematic physicochemical and electrochemical screening of the potentiality of chemically synthesized PANI as an electrode material to provide an overall understanding of the effect of the entire synthesis conditions. We have integrated different methods (TGA-DSC, XRD, SEM, EDX, FTIR, BET, CHNS, XPS, CV, and EIS) to deeply examine the as-synthesized materials and interrogate their electrocatalytic efficiency towards hydrogen evolution reaction, which was chosen as a model reaction of critical importance for H2 production from water splitting. It was found that all the synthesis parameters affect strongly the physical and electrochemical characteristics of the PANI-based materials. Specifically, XPS analysis contributed to identify the oxidation levels of the PANI samples on the basis of oxidizing agents. The outcomes provided by the study delineate a rational pathway for the further design and fabrication of PANI-based metal nanoparticles as advanced electrode materials.

Three dimensional Ni3S2 nanorod arrays as multifunctional electrodes for electrochemical energy storage and conversion applications.

The increasing demand for energy and environmental protection has stimulated intensive interest in fundamental research and practical applications. Nickel dichalcogenides (Ni3S2, NiS, Ni3Se2, NiSe, etc.) are promising materials for high-performance electrochemical energy storage and conversion applications. Herein, 3D Ni3S2 nanorod arrays are fabricated on Ni foam by a facile solvothermal route. The optimized Ni3S2/Ni foam electrode displays an areal capacity of 1602 µA h cm−2 at 5 mA cm−2, excellent rate capability and cycling stability. Besides, 3D Ni3S2 nanorod arrays as electrode materials exhibit outstanding performances for the overall water splitting reaction. In particular, the 3D Ni3S2 nanorod array electrode is shown to be a high-performance water electrolyzer with a cell voltage of 1.63 V at a current density of 10 mA cm−2 for overall water splitting. Therefore, the results demonstrate a promising multifunctional 3D electrode material for electrochemical energy storage and conversion applications.

Nanofilament array embedded tungsten oxide for highly efficient electrochromic supercapacitor electrodes

Nanofilament array embedded metal oxide for a highly efficient electrochemical electrode.

Review on Recent Progress in the Development of Tungsten Oxide Based Electrodes for Electrochemical Energy Storage.

Current progress in the advancement of energy-storage devices is the most important factor that will allow the scientific community to develop resources to meet the global energy demands of the 21st century. Nanostructured materials can be used as effective electrodes for energy-storage devices because they offer various promising features, including high surface-to-volume ratios, exceptional charge-transport features, and good physicochemical properties. Until now, the successful research frontrunners have focused on the preparation of positive electrode materials for energy-storage applications; nevertheless, the electrochemical performance of negative electrodes is less frequently reported. This review mainly focuses on the current progress in the development of tungsten oxide-based electrodes for energy-storage applications, primarily supercapacitors (SCs) and batteries. Tungsten is found in various stoichiometric and nonstoichiometric oxides. Among the different tungsten oxide materials, tungsten trioxide (WO3 ) has been intensively investigated as an electrode material for different applications because of its excellent charge-transport features, unique physicochemical properties, and good resistance to corrosion. Various WO3 composites, such as WO3 /carbon, WO3 /polymers, WO3 /metal oxides, and tungsten-based binary metal oxides, have been used for application in SCs and batteries. However, pristine WO3 suffers from a relatively low specific surface area and low energy density. Therefore, it is crucial to thoroughly summarize recent progress in utilizing WO3 -based materials from various perspectives to enhance their performance. Herein, the potential- and pH-dependent behavior of tungsten in aqueous media is discussed. Recent progress in the advancement of nanostructured WO3 and tungsten oxide-based composites, along with related charge-storage mechanisms and their electrochemical performances in SCs and batteries, is systematically summarized. Finally, remarks are made on future research challenges and the prospect of using tungsten oxide-based materials to further upgrade energy-storage devices.

Design and facile synthesis of defect-rich C-MoS2/rGO nanosheets for enhanced lithium-sulfur battery performance.

We report a simple one-step hydrothermal strategy for the fabrication of a C-MoS2/rGO composite with both large surface area and high porosity for the use as advanced electrode material in lithium–sulfur batteries. Double modified defect-rich MoS2 nanosheets are successfully prepared by introducing reduced graphene oxide (rGO) and amorphous carbon. The conductibility of the cathodes can be improved through the combination of amorphous carbon and rGO, which could also limit the dissolution of polysulfides. After annealing at different temperatures, it is found that the C-MoS2/rGO-6-S composite annealed at 600 °C yields a noticeably enhanced performance of lithium–sulfur batteries, with a high specific capacity of 572 mAh·g−1 at 0.2C after 550 cycles, and 551 mAh·g−1 even at 2C, much better than that of MoS2-S nanosheets (249 mAh·g−1 and 149 mAh·g−1) and C-MoS2/rGO-S composites (334 mAh·g−1 and 382 mAh·g−1). Our intended electrode design protocol and annealing process may pave the way for the construction of other high-performance metal disulfide electrodes for electrochemical energy storage.

The Plate-Like Hexagonal Ni-Fe-Sr Layered Double Hydroxides as Advanced Electrodes for Electrochemical Energy Storage

Some kinds of the plate-like hexagonal layered double complex hydroxides (named Ni-Fe-Sr-LDHs) materials were prepared for energy storage electrodes in this work. It showed good properties with energy densities and cycle life through the electrochemical tests. At 1 A g−1 current density, the specific capacitance of the electrode reached 311.02 F g−1 when the electrolyte was 6 M LiOH. In the long cycle test, the capacitance retention of the electrode maintained at 73.16% after 2000 cycles (current density: 1 A g−1). The morphologies of Ni-Fe-Sr-LDHs were characterized via the scanning electron microscope, transmission electron microscopy and x-ray powder diffraction. The prepared layered double hydroxides were further optimized by doping carbon nanotubes (CNTs). The optimal weight ratio of Ni-Fe-Sr-LDHs to CNTs was 3:1. The specific capacitance in the measurement of galvanostatic charge–discharge increased to 438.74 F g−1, and the stability of long-term cycling was raised to 77.45%. These results indicated that Ni-Fe-Sr-LDHs combined with CNTs would be an ideal electrode material for practical energy storage.

Natural biomass derived hard carbon and activated carbons as electrochemical supercapacitor electrodes

With every moving day, the aspect that is going to be the most important for modern science and technology is the means to supply sufficient energy for all the scientific applications. As the resource of fossil fuel is draining out fast, an alternative is always required to satisfy the needs of the future world. Limited resources also force to innovate something that can utilise the resource more efficiently. This work is based on a simple synthesis route of biomass derived hard carbon and to exploring the possibility of using it as electrochemical supercapacitors. A cheap, eco-friendly and easily synthesized carbon material is utilized as electrode for electrochemical energy-storage. Four different hard carbons were synthesized from KOH activated banana stem (KHC), phosphoric acid treated banana stem derived carbons (PHC), corn-cob derived hard carbon (CHC) and potato starch derived hard carbons (SHC) and tested as supercapacitor electrodes. KOH-activated hard carbon has provided 479.23 F/g specific capacitance as calculated from its cycle voltammograms. A detailed analysis is done to correlate the results obtained with the material property. Overall, this work provides an in depth analysis of the science behind the components of an electrochemical energy-storage system as well as why the different characterization techniques are required to assess the quality and reliability of the material for electrochemical supercapacitor applications.

High-performance layered NiCo2S4@rGO/rGO film electrode for flexible electrochemical energy storage

The rapid development of portable and wearable electronic devices requires novel energy storage devices. Flexible, high-performance electrode materials are critical for meeting the demands yet remain challenging. Here, a rationally designed flexible NiCo2S4@rGO/rGO film constructed with NiCo2S4@rGO frameworks is successfully prepared through a step-wise process (hydrothermal, freeze-drying, vacuum filtration, and then sulfurization/reduction). The NiCo2S4@rGO/rGO film as flexible electrode shows typical battery-type faradaic redox features and exhibits a high specific capacitance of 1100.0 F g−1 at 1 A g−1, a good rate performance of 89.1% capacity retention at 10 A g−1 coupled with long cycling stability of 90.2% after 5000 cycles. The good electrochemical performance is mainly attributed to the loose layered structure and strong interaction between NiCo2S4 and rGO nanosheets, which enhance the diffusion of electrolyte ions/electrons and decreases intrinsic resistance and contact resistance. A flexible hybrid supercapacitor assembled using the NiCo2S4@rGO/rGO film as cathode and the rGO film as anode shows a high energy density of 30.0 Wh kg−1 at a power density of 857.6 W kg−1 at an extended operating voltage of 1.8 V. The method can also be readily adapted for loading other bimetallic sulfides on rGO films, indicative of its feasibility and flexibility to prepare rGO-based hybrid film for high-performance flexible electrochemical energy storage.

Rational fabrication of CoS2/Co4S3@N-doped carbon microspheres as excellent cycling performance anode for half/full sodium ion batteries

Cobalt sulfides have attracted tremendous attention as promising anodes for sodium-ion batteries owing to their low cost, rich types and high theoretical specific capacity. However, the design and application of cobalt sulfides with long cycling stability and high capacity still remains a great challenge. Herein, CoS2/Co4S3@N-doped carbon (CoS2/Co4S3@NC) microspheres obtained via a simple solvothermal and subsequent annealing approach were investigated as an advanced anode material for sodium-ion batteries. It delivers excellent rate capability (650 mAh g−1 at 0.3 A g−1, and 217 mAh g−1 at 6 A g−1) and ultralong-term cycling performance (256 mAh g−1 after 1500 cycles at 4 A g−1, and 239 mAh g−1 after 3000 cycles at 6 A g−1). The extraordinary electrochemical performance of the present material as anode for SIBs was believed to arise from the unique structure advantages of the composite and the good combination as well as the synergistic effects among the components. In addition, FeFe(CN)6//CoS2/Co4S3 full cell was assembled and delivered a reversible capacity of 520 mAh g−1 at 500 mA g−1. This work may provide new directions for constructing promising high-performance SIBs electrodes for electrochemical energy storage.

NiCo2O4/MWCNT/PANI coral-like nanostructured composite for electrochemical energy-storage applications

In this work conductive polymeric polyaniline (PANI) nanofibers are prepared by a fast chemical method and in-situ assembled with electrostatic double-layer (multi-wall carbon nanotubes, MWNTs) and pseudocapacitive materials (metal oxides) to construct MWCNT/PANI, NiCo2O4/PANI and NiCo2O4/MWCNT/PANI coral-like nanostructured composites for electrochemical energy storage electrodes. X-ray diffraction, Raman spectroscopy, nitrogen adsorption isotherms, and scanning electron microscopy (SEM) are used to analyze the structure of the resulting composite materials. Afterwards, electrochemical energy storage electrodes are prepared using the obtained nanostructured composites on glassy carbon (GC), and electrochemical tests are performed. The specific capacitance of PANI nanofibers, MWCNT/PANI, NiCo2O4/PANI and NiCo2O4/MWCNT/PANI coral-like nanostructured composites are 402, 645, 617 and 725 F/g, respectively, at the current density of 1 A/g. The analysis of electrochemical impedance spectroscopy (EIS) data in this work reported perfectly by constant phase element (CPE) and provided trustable method to compare nanostructured composites.

3D metal dendrite-derived petaloid shaped NiFe2O4@ NFM as binderless electrode for oxygen evolution reaction and electrochemical energy storage

Two-dimensional nanosheets materials anchored on the surface of ordered dendritic array substrate not only realizes the multiple scale assembly of materials, but also enables the construction of self-supporting electrodes. In this work, we fabricate the Ni–Fe alloy dendritic array matrix by the facile electrodeposition process for the first time. It can provide a large number of vertical paths for electrolyte ions, electron transfer and gas overflow, which further helps to improve the electrochemical performance of electrode. Whereafter, the metal on the surface of dendrite is converted into NiFe2O4 via in situ calcination oxidation method. The NiFe2O4@NiFe dendrite matrix electrode is characterized by Field emission scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy analysis. During the oxygen evolution reaction measurement, the as-prepared NiFe2O4@NFM-3 requires a low overpotential of 234 mV (vs.RHE) to arrive 10 mA cm−2 current density. Furthermore, the NiFe2O4@NFM-3 electrode reveals the high area capacitance about 1560 mF cm−2 at current density of 1 mA cm−2. The electrochemical performances test results demonstrate that this fiber electrode can serve as the bifunctional electrode in oxygen evolution reaction (OER) and energy storage.

Chitosan-assisted synthesis of wearable textile electrodes for high-performance electrochemical energy storage

Through a facile “dipping and drying” process, reduced graphene oxide, here simply referred to as “graphene”, was successfully coated onto a commercial textile substrate, resulting in a high-performance supercapacitor electrode with excellent flexibility and stretchability. With the assistance of difunctional chitosan (for dispersing and gluing), a high graphene loading amount of 5.5 mg cm−2 was achieved on cotton textile within 10 soaking times. The graphene@cotton-10 had a low sheet resistance of 1.75 Ohm sq−1, which merely increased 0.51 and 0.78 Ohm sq−1 when being bent at 180° and stretched with 100% strain, respectively. In a three-electrode configuration, the areal specific capacitance of the graphene@cotton-10 reached up to 232 mF cm−2 at the current density of 1 mA cm−2, which was superior to most of the carbon@textile flexible electrodes reported so far. The resulting graphene@cotton-10 symmetrical supercapacitor had a decent energy density of 4.38 μWh cm−2 at 5 mW cm−2. Cycling test revealed the supercapacitor had more than 80% retention of its initial capacitance after 5000 cycles at 5 mA cm−2, demonstrating an outstanding long-term durability. Furthermore, the synthesis methodology established in this study is simple, efficient and environment-friendly, which possesses a great potential for large-scale practical applications.

(Invited) 2D MXenes As Building Blocks for Assembly of High-Performance Electrodes for Electrochemical Energy Storage

Two-dimensional (2D) transition metal carbides/nitrides (MXenes) have shown promise for a range of applications due to their unique physical and chemical properties. The high electrical conductivity, 2D and layered structure, and rich surface chemistry of MXenes have sparked great interest in their properties as electrode materials for energy storage devices. MXenes are particularly of high interest because they can store charge in the bulk of the electrode through ultrafast intercalation of ions and fast and reversible redox reactions. To date, about 30 different MXenes with a general formula of Mn+1XnTx (M is a transition metal, X is carbon and/or nitrogen, n=1,2, and 3, and Tx represents different functional groups present at their surface) are synthesized by selective etching of the A layer atoms (i.e. Al) from MAX phases (e. g. Ti2AlC), a large group of layered ternary carbides and nitrides.1 However, similar to other 2D materials, the applications of MXenes in batteries and supercapacitors is dependent on their assembly into electrode structures with high electrical and ionic conductivities. The main focus of this talk is our group’s recent research on the assembly of MXene flakes into electrode structures with high energy and power densities. We have found that the electrochemical properties of MXene electrodes are highly dependent on the size of MXene flakes used in their fabrications.2,3 Controlling the flake size in the electrode structures leads to significant improvements in their specific capacitance and rate capability. Furthermore, our recent studies on the assembly of multilayer MXenes films and particles using electrostatic assembly methods will be discussed. The electrodes fabricated by these methods show superior chemical and electrochemical stabilities as well as energy storage capability.4 Finally, our work on 3D assembly of MXenes through a versatile 3D printing process will be presented. References (1) Anasori, B.; Lukatskaya, M. R.; Gogotsi, Y. 2D Metal Carbides and Nitrides (MXenes) for Energy Storage. Nat. Rev. Mater. 2017, 2 (2), 16098. https://doi.org/10.1038/natrevmats.2016.98. (2) Kayali, E.; VahidMohammadi, A.; Orangi, J.; Beidaghi, M. Controlling the Dimensions of 2D MXenes for Ultrahigh-Rate Pseudocapacitive Energy Storage. ACS Appl. Mater. Interfaces 2018, 10 (31), 25949–25954. https://doi.org/10.1021/acsami.8b07397. (3) VahidMohammadi, A.; Moncada, J.; Chen, H.; Kayali, E.; Orangi, J.; A. Carrero, C.; Beidaghi, M. Thick and Freestanding MXene/PANI Pseudocapacitive Electrodes with Ultrahigh Specific Capacitance. J. Mater. Chem. A 2018, 6 (44), 22123–22133. https://doi.org/10.1039/C8TA05807E. (4) VahidMohammadi, A.; Mojtabavi, M.; Caffrey, N. M.; Wanunu, M.; Beidaghi, M. Assembling 2D MXenes into Highly Stable Pseudocapacitive Electrodes with High Power and Energy Densities. Adv. Mater. 2019, 31 (8), 1806931. https://doi.org/10.1002/adma.201806931.

Low-Temperature Deposition Manufacturing: A Versatile Material Extrusion-Based 3D Printing Technology for Fabricating Hierarchically Porous Materials

Low-temperature deposition manufacturing (LTDM) is a technology that combines material extrusion-based 3D printing and thermally induced phase separation (TIPS) into one process. With this feature, both the merits of 3D printing and TIPS can be incorporated including complex geometries with tailorable ordered macroporous features facilitated by 3D printing and microporous/nanoporous features endowed by TIPS. These macroporous/microporous/nanoporous combined structures are important to some important applications such as tissue engineering scaffolds, porous electrodes for electrochemical energy storage, purification, and filtering applications. However, the unique advantages and potential applications of LTDM have not been fully recognized and exploited yet. In this review, we will discuss the origin, principle, advantages, processes, and machine setup of LTDM technology with an emphasis on its unique advantages in fabricating porous materials. Then, current applications of LTDM including porous tissue engineering scaffolds and emerging porous electrodes for electrochemical storage will be described. The versatility of LTDM including its capability of processing a wide range of materials, multimaterial and gradient structures, and core-shell structures will be introduced. Finally, we will conclude with a perspective and outlook on the future development and applications of LTDM technology.

In-built template synthesis of hierarchical porous carbon microcubes from biomass toward electrochemical energy storage

Carbon materials are appealing as electrodes for electrochemical energy storage due to their high surface area and tunable pore structures. In this work, hierarchical porous carbon microcubes (PCM) are synthesized through in-built template method from renewable agaric. Cubic MnO@C composite is obtained by hydrothermal treatment of agaric and subsequent calcination with the presence of manganese source. The in-built MnO-template is sacrificed by acid etching to prepare PCM sample with high specific surface area of 1052 m2 g−1, rational pore size distribution, and self N-doped property. The refined architecture endows PCM sample with significantly improved performance including high specific capacitance, superior rate capability and long-term cyclic stability when employed as electrodes for both lithium-ion batteries and supercapacitors. We believe that this work proposes a new concept to construct carbon architecture with well-refined, hierarchical porous structure for electrochemical energy storage.

Germanium Nanowire Battery Electrodes with Engineered Surface-Binder Interactions Exhibit Improved Cycle Life and High Energy Density without Fluorinated Additives

Nanostructured Group-IV materials hold great promise as high-capacity alloying electrodes for electrochemical energy storage. However, in order to stabilize their cycling performance, it has been n...

Binary cobalt-iron oxides magnetic nanocomposites embedded porous carbon lawn with inherent [sbnd]N doping as promising electrode material for supercapacitors and Li-ion batteries

The next generation energy demands require to address the alternative energy resources and as well the energy storage technologies. The electrochemical supercapacitors and lithium ion batteries prove to be attractive devices to overcome the faced community challenges. There is a need to develop an innovative material owing high surface area with higher electrical & ionic conductivity and low diffusion distance for electrochemical energy storage electrodes. To this end, a unique electrode material is developed with these admirable properties for energy storage applications towards both directions such as, electrochemical supercapacitors and an anode material for lithium ion batteries. Nanostructured materials based on metallic binary oxides of cobalt and iron embedded in porous carbon lawn with inherent nitrogen doping are synthesized by dry-chemistry calcined process. The success of synthesis is later proved by materials characterizations. The magnetic nature of present electrode material with correlation of crystallite and morphological analysis revealed the signs of their excellence in energy storage behaviour. The testing of electrode material for electrochemical supercapacitors and lithium ion batteries depicted enhance performance with durable and long-run recycled capabilities.

Few-layer MoS2 wrapped MnCO3 on graphite paper: A hydrothermally grown hybrid negative electrode for electrochemical energy storage

This article puts forward a novel approach of combining the battery-type charge storage material, Mn(OH)2, indirectly with the two-dimensional material, MoS2, to develop the composite MnCO3@MoS2 (designated as MCMS). A single-step facile hydrothermal method is described here for the synthesis of MCMS on a low-cost graphite substrate. Furthermore, this as-synthesized binder-free electrode is utilized as the negative electrode of an all-solid state asymmetric alkaline supercapacitor, employing NiCo2O4 as the high specific energy positive electrode material. The overall asymmetric cell is shown to achieve a high specific energy of 48.97 W.h.kg−1 at 600 W.kg−1 and a high specific power of 12 kW.kg−1 at 11.33 W.h.kg−1, within a potential window of 1.2 V. Also, the composite electrode notably retains 86.5% of its gravimetric discharge capacity after 10,000 cycles with complete retention of its coulombic efficiency. The present work contributes to the development of a facile strategy for the preparation of non-carbonaceous hybrid materials suitable for high specific energy negative electrodes.

Laser-induced nitrogen-doped hierarchically porous graphene for advanced electrochemical energy storage

Development of one-step processes combining hierarchical porous architecture with heteroatom doping control has remained a challenge. This is especially important for structure-engineered graphene materials as high performance active electrodes for energy and advanced applications. Herein, we present a facile and general approach for synthesizing patternable, nitrogen-doped and hierarchical porous graphene from graphene oxide/urea mixture using high-repetition picosecond laser in ambient air. Impressively, the highest areal capacitance of laser-induced nitrogen-doped graphene (LING) is 60.7 mF/cm2, which is about 3 times that of undoped porous graphene. After 25,000 consecutive cycles of galvanostatic charge-discharge at a current density of 10 mA/cm2, the optimized LING electrode maintained 98.7% of its original capacitance. Most importantly, the as-prepared LING electrode material has high energy and power density due to the synergistic effect of hierarchical porous structure, nitrogen-doping and engineering defects. The proposed laser one-step synthesis of LING may also be applied to other heteroatom-doped hierarchical porous graphene-based electrodes for high-performance electrochemical energy storage.

Functionalized N-Doped Carbon Nanotube Arrays: Novel Binder-Free Anodes for Sodium-Ion Batteries.

Boosting electrochemical sodium storage properties is achieved by utilizing functionalized N-doped carbon nanotube arrays (NCNAs) as anode materials. The NCNA anodes are first fabricated by self-polymerization of dopamine on cobalt hydroxide nanorod arrays as the template. The NCNAs with diameters of 100-120 nm are grown vertically to Ni foam, forming self-supported nanotube arrays. Such a structure has attractive advantages including large porosity and surface area, good electrical conductivity and mechanical strength. Consequently, the NCNAs are demonstrated to achieve excellent sodium storage performances with high capacity (335 mA h g-1 at 100 mA g-1), good rate capability (140 mA h g-1 at 2 A g-1), and superior capacity retention of 90.9% after 500 cycles. Especially, high performance is verified in the assembled full cells by using an NCNA anode and Na3V2(PO4)3/C cathode. The developed synthetic strategy provides an effective approach for the fabrication of advanced heteroatom-doped carbon-based electrodes for electrochemical energy storage.