Electrodes For Energy Storage Applications Research Articles

Design and fabrication of interconnected 2D/3D NiS/Ni3S4 composites supercapacitor electrodes for energy storage applications

Design and fabrication of interconnected 2D/3D NiS/Ni3S4 composites supercapacitor electrodes for energy storage applications

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.

Treatment of Biowaste for Electrodes in Energy Storage Applications: A Brief Review

Proper and innovative waste management methods still pose a major concern in our present world. Continuous accumulation of biowaste from bio-processing industries, household, organic residues and so on makes the environment polluted and endangers the health of man and other animals. The common waste management methods which include direct dumping into water bodies, open-air combustion, and as land fillers are obsolete and are the major causes of environmental pollution. Conversion of biowastes into valuable materials aids proper waste management, and helps to attain a cleaner environment, in addition to the fact that wastes are turned into wealth. Biowastes are rich in carbon and can serve as excellent precursors for the synthesis of important carbon materials such as activated carbon, graphene, carbon nanotubes etc. Three important methods of converting biowastes into carbon materials are discussed in this review. The electrochemical, adsorption, and electrocatalytic properties of the materials and the applications in electrochemical energy storage devices are also discussed in brief. This review focuses on the synthesis of carbon materials from biowaste residues and their use in developing electrode materials for batteries and supercapacitors. Future perspectives on the need to exploit greener technology for the conversion of biowastes into important carbon materials should be considered.

MXene/PPy nanocomposite as an electrode material for high-capacity Na-ion batteries investigated from first principle calculation

Mxene/Polypyrrole (Mxene/PPy) nanocomposite films are gaining importance for designing electrodes for energy storage applications. In this work, density functional theory (DFT) simulation is used to investigate the energy storage properties of PPy-based nanocomposite. The adsorption sites, adsorption energies, and electronic structures of Na storage abilities of Ti2CO2−MXene/PPy nanocomposite are all thoroughly investigated. The findings show that Na ion in Ti2CO2−MXene/PPy nanocomposite has high adsorption energy of −0.44 eV and a narrow energy bandgap of 0.02. The adsorption distance of the Na atom on the nanocomposite is relatively high. And according to charge transfer analysis from the electron density difference study, physisorption is the dominating adsorption mechanism for the Na-ion in the substrate. The Na-ion adsorbs onto the nanocomposite at 2.95 Å from the surface of the Ti2CO2−MXene and at a distance of 2.60 Å from the PPy. The projected density of state (PDOS) reveals the ability of the electrode to transmit electrons during the electrochemical process. This suggests that the Ti2CO2−MXene/PPy nanocomposite might be a promising Na-ion electrode material for battery use. As such, based on the nanocomposite's metallicity, chemical stability, and capacity to absorb sodium ions with low adsorption energy, which can result in effective Na release. It may be recommended for use as an anode.

Gel combustion synthesized NiMoO4 anchored polymer nanocomposites as a flexible electrode material for solid state asymmetric supercapacitors

Recent research has focused on the search for new electrode materials to improve the specific capacitance of supercapacitors. Conductive polymers and metal oxides have been extensively tested as electrode materials for supercapacitors. Incorporating both conductive polymers and metal oxides into a composite provides excellent results for the electrochemical performance of supercapacitors. In this present work, we have fabricated the nanoscale α-NiMoO4 particles that enwrapped on electronically conducting polymer nanocomposites (PNCs) based on Polyvinyl alcohol (PVA)/Poly(vinyl) pyrrolidone (PVP) for supercapacitor applications. The different concentrations of PVA/PVP with α-NiMoO4 loaded polymer nanocomposites were developed by using a solution casting method. All the polymer nanocomposites have been subjected to Scanning Electron Microscopy (SEM), Fourier Transforms Infrared (FTIR), X-ray diffraction (XRD), and electrochemical studies. The prepared PNCs surface morphology has been acquired as a non-uniform rod-like structure. The electrochemical performances of the prepared PNCs have been investigated and the resultant value of the maximum specific capacitance is 15.56 F g−1 for 1 wt % of α-NiMoO4 nanoparticles(NPs) loaded polymer blended electrode at a scan rate of 5 mVs−1. The prepared PNCs exhibit 97.12% of columbic efficiency studied by using two electrode systems at room temperature in an aqueous electrolyte solution of 3 M KOH. From these investigation, it has been revealed that the PVA/PVP/α-NiMoO4 composites could be portable and flexible electrodes for energy storage applications.

Design and additive manufacturing of optimized electrodes for energy storage applications

Supercapacitors exhibit fast charging/discharging ability and have attracted considerable attention within the automotive, aerospace, and telecommunication industries. Porous carbons, prized for their high electrical conductivity and high surface area, have been attractive candidates for supercapacitor electrodes. Moving to thick electrodes is one strategy to further increase energy density due to a higher volume fraction of active material. However, thick electrodes suffer from sluggish charged species transport, which is why thin electrodes are currently favored. In this work, we investigate the use of computational optimization and additive manufacturing to design and fabricate thick porous electrodes with improved performance. Electrode performance was maximized by designing their morphologies via topology optimization and printing by projection micro stereolithography (PμSL) using commercial resin (PR48). The PR48 resin was then pyrolyzed (PR48-P) to create the final conductive electrode. The optimized PR48-P electrodes exhibited 99% improvement in capacitance compared to control electrodes printed with cubic lattice morphologies. To further improve performance, we formulated a resin combining graphene oxide (GO) and trimethylolpropane triacrylate (TMPTA). Electrodes printed with 3 wt% GO in TMPTA exhibited improved capacitance retention after pyrolysis compared to the PR48-P electrodes. This work demonstrates the benefits of using topology optimization to design electrodes and material development to improve functional properties of 3D printable electrodes.

Novel macaroni‐sponge‐like pore structure biomass (Zingiber officinale Rosc. leaves)‐based electrode material for excellent energy gravimetric supercapacitor

AbstractBACKGROUNDBiomass‐based porous carbon as the basic component of electrodes has received wide interest as a renewable energy storage device with high chemical–physical stability and environmental friendliness. Therefore, novel biomass waste based on Zingiber officinale Rosc./red ginger leaves was synthesized as an electrode‐based carbon material with an abundance of unique macaroni‐sponge‐like hierarchical pore structure, as well as good chemical, physical and economic performance. Template/metal–organic framework‐free red ginger leaf‐based hierarchical porous carbon (RGPC) was prepared using a facile and zero‐residue technique as electrode material for supercapacitor application.RESULTSAdditionally, ZnCl2 impregnation with concentrations of 0.1, 0.3 and 0.5 mol L−1 was utilized for increasing the active sites between electrode and electrolyte ions through interconnecting microchannels. The combination of macaroni‐sponge‐like structure, amorphous nature, optimum specific surface area and availability of oxygen functional groups as a self‐doping heteroatom of RGPC‐0.3 greatly optimized the electrochemical performance of symmetric supercapacitor cells. The RGPC‐0.3 electrode had an ideal specific capacitance of 215.76 F g−1 with a specific energy of 29.966 Wh kg−1 and maximum specific power of 108 W kg−1 at 1 mV s−1 in a symmetric supercapacitor system. Furthermore, a relatively good coulombic efficiency of 71.01% was obtained with a low equivalent series resistance of 0.098 Ω.CONCLUSIONSThis study provides insight into the generation of unique hierarchical porous carbon as a basic component of electrodes for energy storage applications with high electrochemical performance through the utilization of waste red ginger biomass with a simple, facile and cost‐effective strategy. © 2022 Society of Chemical Industry (SCI).

Exploring the redox characteristics of porous ZnCoS@rGO grown on nickel foam as a high-performance electrode for energy storage applications.

A supercapattery is a device that combines the properties of batteries and supercapacitors, such as power density and energy density. A binary composite (zinc cobalt sulfide) and rGO are synthesized using a simple hydrothermal method and modified Hummers' method. A notable specific capacity (Cs) of 1254 C g-1 is obtained in the ZnCoS@rGO case, which is higher than individual Cs of ZnS (975 C g-1) and CoS (400 C g-1). For the asymmetric (ASC) device (ZnCoS@rGO//PANI@AC), the PANI-doped activated carbon and ZnCoS@rGO are used as the cathode and anode respectively. A high Cm of 141 C g-1 is achieved at 1.4 A g-1. The ASC is exhibited an extraordinary energy density of 45 W h kg-1 with a power density 5000 W kg-1 at 1.4 A g-1. To check the stability of the device, the ASC device is measured for 2000 charging/discharging cycles. The device showed improved coulombic efficiency of 94%. These findings confirmed that the two-dimensional materials provide the opportunities to design battery and supercapacitor hybrid devices.

In-Situ Assembly of MoS2 Nanostructures on EHD-Printed Microscale PVDF Fibrous Films for Potential Energy Storage Applications.

Three-dimensional (3D) printing has been widely utilized to fabricate free-standing electrodes in energy-related fields. In terms of fabrication, the two most challenging limitations of 3D printed electrodes are the poor printing resolution and simple structural dimension. Here we proposed a novel process to fabricate molybdenum disulfide-polyvinylidene fluoride (MoS2-PVDF) hierarchical electrodes for energy storage applications. The 20-layer microscale PVDF films with a stable fiber width of 8.3 ± 1.2 μm were fabricated by using electrohydrodynamic (EHD) printing. MoS2 nanostructures were synthesized and assembled on the microscale PVDF fibers by using hydrothermal crystal growth. The structural and material investigations were conducted to demonstrate the geometrical morphology and materials component of the composite structure. The electrochemical measurements indicated that the MoS2-PVDF electrodes exhibited the typical charge-discharge performance with a mass specific capacitance of 60.2 ± 4.5 F/g. The proposed method offers a facile and scalable approach for the fabrication of high-resolution electrodes, which might be further developed with enhanced specific capacitance in energy storage fields.

Facile synthesis of ultrathin Bi(OH)SO4·H2O nanosheets and battery-like electrode for symmetric supercapacitors

The phase engineering of Bi(OH)SO4·H2O nanosheets is proposed as a simple, adaptable, and cost-effective solution for the combustion of Bi2O3 using H2SO4. This study revealed that the formation of Bi(OH)SO4·H2O with a nanosheet-like morphology. The synthesized nanosheets were employed as electrode materials for electrochemical storage devices. The estimated capacity of the Bi(OH)SO4·H2O electrode is 327.69 mAh g–1 at 1 A g–1. Solid-state coin-cell-type symmetric supercapacitor devices (CSSDs) were developed. The fabricated CSSDs exhibit a high specific capacity (33 mAh g–1 at 1.1 A g–1), energy density (62.23 Wh kg–1), and power density (2074.11 W kg–1) with a significant retained energy density of up to 32.98 Wh kg–1 at 10794.51 W kg–1. Furthermore, they exhibited cycling stability at 5.5 A g–1, maintaining 76.65% of its initial capacity after 10,000 cycles. In addition, to investigate the device performance in real time, two CSSDs were connected in series to power a red LED. The obtained results provide insights into bismuth-based electrodes for energy storage applications.

Low-tortuosity carbon electrode derived from Wood@ZIF-67 for supercapacitor applications

Constructing a thick electrode with excellent electrochemical performance using carbon materials remains a significant challenge. The crucial factor is that traditional thick electrodes typically result in poor ion transport and conductivity. As a result, a low-tortuous, hierarchically porous, aligned channels, and high-performance thick electrode was constructed without the need for the electrode's additional complex structural design. ZIF-67 increases the number of ion storage sites and pore structure of carbon materials, whereas Co metal improves the degree of graphitization and electrical conductivity of carbon materials during the carbonization process. Carbonized Wood@ZIFs (CWZ) with a high specific capacity of 5155.3 mF cm−2 is achieved. Notably, a supercapacitor assembled by CWZ-3 shows an energy density of 101.74 μWh cm−2 and a power density of 5 mW cm−2. The hierarchical pore structure, low tortuosity, high content of N-doping, and convenient ion transport channels all contribute to the material's excellent performance. Density functional theory calculations demonstrate that N-doping carbon materials with nitrogen promote their adsorption and storage capacity for electrolyte ions. The monolithic strategy demonstrated in this work paves the way for the development of lightweight carbon-based thick electrodes for energy storage applications.

Natural fibers and zinc hydroxystannate 3D microspheres based composite paper sheets for modern bendable energy storage application

AbstractFor modern high‐tech flexible energy storage devices, it becomes important to synthesize micro‐/nanostructures as per the required shape and morphology with superior physical and electro‐active characteristics. This work shares the fabrication and characterization of ZnSn(OH)6 (Zinc hydroxystannate [ZHS]) prepared by facile microwave‐assisted technique and furthermore converted into flexible sheets by employing lignocelluloses (LC) known as natural fibers, collected from Carica papaya leaf petiole as a substrate to provide the flexible matrix. X‐ray diffraction measurements confirm the successful crystalline structure of ZHS. Scanning electron microscopy and transmission electron microscopy showed the solid spherical structure of ZHS microspheres. Fourier transform infrared spectrometry and Raman spectroscopy confirmed the composite formation of ZHS and LC‐based composite sheets (ZHS/LC sheets). Electrochemical measurements that is, cyclic voltammetry (CV), Galvanostatic charge/discharge, and electrochemical impedance (EIS) spectroscopy revealed the electroactive behavior of ZHS/LC paper sheets as working electrode for energy storage applications. CV measurements revealed the specific capacitance of 100 F/g and EIS measurements confirmed the decrease in the resistance of LC fiber after the growth of ZHS microspheres. Presented flexible ZHS based paper sheets will be highly feasible for the modern bendable/flexible/disposable energy storage applications.

Flexible and freestanding PANI: PSS/CNF nanopaper electrodes with enhanced electrochemical performance for supercapacitors

With the fast-expanding markets of portable and wearable electronics, the development of sustainable, cost-effective, and flexible electrodes for energy storage applications is critical. Herein, a flexible, freestanding, binder-free polyaniline: poly (sodium 4-styrene sulfonate)/cellulose nanopaper (PANI: PSS/CNP) electrode was prepared using an in situ polymerization with a facile vacuum filtration approach. The low-cost and environmentally friendly nanocellulose with a three-dimensional (3D) hierarchical porous structure was chosen as the substrate that not only reduced the production cost but also improved the electrolyte absorption, flexibility, and mechanical strength for PANI: PSS/CNP. The freestanding and binder-free structure simplifying the preparation process and increasing the mass loading of the active material in the electrode was beneficial to maximizing electrode utilization. Due to the effective combination of cellulose and PANI: PSS complex, PANI: PSS/CNP electrode exhibited high specific capacitance (2.56 F/cm2) with excellent cycling stability (81.5% capacitance retention, 8000 cycles), mechanical strength, conductance stability, and flexibility. A symmetric supercapacitor device was constructed with PANI: PSS/CNP electrodes, showing outstanding areal specific capacitance (460 mF/cm2) and high energy density (40.9 μWh/cm2). Our work offers a novel and economical approach for the future production of sustainable, low-cost, and energy-efficient flexible electrode materials.

In-situ measurement of drying and electrochemical-cycling-induced mechanical behavior and delamination of polypyrrole electrodes for energy storage applications

Delamination during the fabrication and operation of thick electrodes is one of the major instabilities that prevent their utility for high energy density electrochemical devices. In this study, we investigate the deformation and delamination of polypyrrole (pPy) film electrodes using in-situ measurements of curvature/stress. At the beginning of drying process, the water in the film exited continuously, while the film did not deform accordingly. Then, the film rapidly contracted near the end of the evaporation process and remained in its equilibrium contracted state. The film deformation was found to be caused by the evaporation of moisture near the polymer chain, whereas it was not affected by the evaporation of free water in the pores, causing the mismatch between the deformation and evaporation. Importantly, film delamination was identified in real time as the rapid stress drop corresponded to the peeling of the film from the substrate. The interfacial fracture energy was quantified to estimate the adhesion strength of the interface with various treatments. Moreover, electrochemical-cycling-induced delamination was successfully identified based on the type of delamination. We believe this study would be beneficial for both the development and operation of thick electrodes with high energy density and stability.

A High-Energy Density Li-Ion Hybrid Capacitor Fabricated from Bio-Waste Derived Carbon Nanosheets Cathode and Graphite Anode.

The Li‐ion hybrid capacitor (LIHC) system explores the possibility of achieving both high energy and power density in a single energy storage system with an intercalation anode and capacitive cathode. However, to achieve a high power and energy‐based system, the properties of the cathode electrode material are vital. Here, bio‐waste plant stem‐derived activated porous carbon is explored as a cathode for LIHC application. A specific surface area of 1826 m2 g−1, enhanced degree of crystallinity, and graphitization results for porous carbon from activation by potassium hydroxide. When employed as supercapacitor material, the device exhibits good rate capability, energy, and power attributes with a specific capacitance of 116 F g−1 (1 A g−1). Simultaneously when tested for LIHC application the formulated device shows good capacity retention for 2500 cycles with a high energy density of 125 Wh kg−1 at a power density of 69 W kg−1. The work demonstrates unique, cost‐effective strategy to develop a crystalline high surface area carbon from any such bio‐waste sources to be employed as potential electrodes for energy storage applications.

Carboxymethyl cellulose mediated growth of V2O5 nanorod by green strategy for energy storage utilization using electrochemical studies

Vanadium pentoxide has the most exciting oxidation states, but, Vanadium pentoxide (V2O5) has low capacitance due to poor electrical conductivity and ionic diffusivity. So, encapsulating pentoxide in carbonaceous materials or metals, shrinking it to the nanoscale, or changing its morphology can improve capacitance performance. Herein, we describe a green synthesis of V2O5NPs with carboxymethyl cellulose (CMC) that typically acts as a reducing and stabilizing agent using the -COOH and -OH group. The physicochemical characterization of prepared samples reveals the prominent peak in UV–vis spectra at 265 nm confirming the formation of V2O5NPs with particle sizes between 200 and 220 nm. The theoretical surface area for the nanocomposite was 76.5 m2/g. The calcination temperature is essential to determine a material's specific capacitance. Due to decreased oxide agglomeration, the V2O5-green modified electrode exhibits superior electrochemical performance around 223 F g−1 than Ac alone (160 F g−1). The finding demonstrated excellent cyclic stability with reduced fluctuation in capacitance. Because of its exceptional electrochemical performance and simplicity of access, this AC/V2O5 nanocomposite can be helpful as an electrode for energy storage applications.

Bismuth oxide-doped graphene-oxide nanocomposite electrode for energy storage application

Nanocrystalline and porous bismuth oxide-doped graphene oxide nanocomposite (Bi2O3-GO NC) electrode material synthesized via microwave irradiation method has been envisaged for supercapacitor application. Surface morphology, elemental configuration, phase purity, surface area, porosity, and binding energy etc., are initially screened and then preferred in electrochemical measurement analysis. The as-obtained Bi2O3–GO NC electrode adduces a better performance with quasi-faradaic redox reactions in electrochemical measurements over pristine GO in 6 M KOH electrolyte solution. The specific capacitance of the Bi2O3–GO NC electrode measured at current densities 5–14 A/g is varied from 1250 to 933 F/g. The as-assembled Bi2O3–GO//Bi2O3–GO symmetric supercapacitor device reveals an exceptional electrochemical performance with 25.83 W-h/kg specific energy at 337 W/kg specific power, and excellent stability of about 80% for 5000 cycles, evidencing usability potential of metal oxide-GO composite electrode materials over solitary carbonaceous electrode. A demonstration of 42 LEDs ignited with full-bright intensity supports our claim as well.

Electrochemical synthesis of MnO 2 / NiO / ZnO trijunction coated stainless steel substrate as a supercapacitor electrode and cyclic voltammetry behavior modeling using artificial neural network

Considering the limit of resources and the frequent use of energy, energy storage is nowadays the subject that everyone cares about. In the present work, we investigate trijunction metal oxides as supercapacitor electrode for energy storage application. A MnO2/NiO/ZnO trijunction electrode is synthesized for the first time using a successive three electrochemical deposition steps onto stainless steel (SS) substrate. This approach can effectively yield a good distribution and adhesion of all metal oxides onto the substrate with enhanced hydrophilicity and wettability. The specific capacitance of this trijunction electrode, as studied by cyclic voltammetry was higher than that of individual metal oxide electrodes. The maximum specific capacitance was estimated to be 1569.75 g−1 at a scan rate of 5 mV s−1. The enhanced electrochemical performance of this trijunction electrode compared to single metal oxide electrodes (MnO2, NiO, or ZnO) is mainly due to the improvement of ion and electron transportation pathways in the combination of three metal oxides electrode. In addition, this study presents an Artificial Neural Network (ANN) model to predict cyclic voltammetry behavior of the prepared trijunction supercapacitor electrode, with a high satisfactory performance for the predicted performance with <0.05% error. The low and simply synthesized hierarchical trijunction electrode with superior electrochemical performance and the good correlation between experimental and theoretical results prove huge potential for its practical application in supercapacitors (SCs).

Galvanically Displaced Noble Metal Nanoparticles Onto Electrosprayed Graphene-CNT Electrodes for Lithium-Ion and Fuel Cell Applications

Advanced lithium-ion batteries (LIB) and Fuel Cells demonstrate promise as the next generation energy storage and conversion (ESC) technology especially as it pertains to wearable technology and electric vehicles. Although LIB dominate the battery market (>90%) due its reliability, long cycle life, and market maturity, different and more innovative ways to improve the chemistry of the electrode structure must be discovered in order to reduce the cost of materials, dendritic issues at the solid-electrolyte interphase (SEI) layer, and improve upon the limited anode capacity (graphite theoretical capacity 372 mAh g-1). Fuel cells are also promising renewable energy sources due to their high energy densities and scalability. However, both LIB and Fuel Cells are limited by the 3D materials that enable their enhanced electrochemical and catalytic performance. We propose a platform methodology for the synthesis of 3D electrodes with carbon nanomaterials and noble metals. The enhanced electrical, thermal, chemical, and mechanical stability of graphene and carbon nanotubes (CNTs) offer an ideal platform for electrode design for energy storage applications. Here we utilize spontaneous galvanic displacement driven by reduction potential difference to produce three-dimensional (3D) graphene-CNT-noble metal nanoparticle 3D electrode without the use of any harsh chemical reducing agents. A graphene-CNT slurry with a poly(acrylic acid) (PAA) binder is air-controlled electrosprayed onto copper foil to create 3D composite thin film electrodes. Although noble metals are expensive materials to be used in LIB, we propose a new approach for synthesizing conductive electrochemically stable electrodes. We demonstrate a spontaneous technique to reduce the noble metal salts by galvanically displacement with the copper substrate to deposit noble metal nanoparticles onto the graphene-CNT electrode. The noble metal salt solutions (HAuCl4, K2PtCl4, and Na2PdCl4) are drop casted onto the resulting copper supported graphene-CNT electrodes to enable electroless noble metal nanoparticle deposition. Scanning electron microscopy (SEM) imaging confirms that the carbon nanomaterials are integrated with noble metal nanoparticles forming an overall 3D electrode structure. Raman spectroscopy verifies the characteristic D-band, G-band, and 2D-band peaks from the graphitic structure within the 3D carbon and noble metal nanostructure. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) are used to characterize the electrochemical properties of the electrodes. We demonstrate that the use of an energy-free and spontaneous process based on the difference in thermodynamic reduction potentials as the driving force for producing carbon nanomaterial/noble metal nanostructured electrodes for batteries and fuel cells. This process is a more simple, scalable, and cost-efficient alternative to current methods for developing lightweight and catalytic electrodes for energy storage applications, such as lithium-ion batteries, lithium-air batteries, and fuel cells. Raman Spectroscopy is used to confirm the presence defects on the oxidized carbon nanotube and graphene oxide surface. Scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDX), and x-ray diffraction (XRD) were used to characterize the morphology of the 3D carbon-noble metal structure and the surface elemental composition. Electrochemical characterization techniques such as electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), performance testing for oxygen reduction reaction (ORR), hydrogen evolution reaction (HER), and potentiostatic measurements are used to characterize the areal specific resistance (ASR), areal capacitance, electrochemical surface area, initial Coulombic efficiency (ICE), rate capability and cycling performance, and electrochemical stability, respectively.

Operando Tracking of Ionic and Electronic Percolation in Electrodes for Energy Storage Application Using AC-in Plane Impedance

Achieving efficient electronic and ionic electrode percolation is one of the most important parameters to improve batteries and supercapacitors power performance. Various electrical and electrochemical techniques (Cyclic voltammetry, Electrochemical Impedance Spectroscopy, EQCM, SECM, in-situ XRD, etc) can be used to assess the electronic and ionic transport properties in these electrodes. However, there are only few studies and techniques on tracking the change in resistance of an electrode during electrochemical polarization [1, 2, 3], which plays a key-role on its electrochemical performance.In this study, we propose a new method to achieve operando resistance measurement under alternative current (AC), that we’ll call in-plane impedance measurement, under bias potential. In these experiments, the electrodes are deposited onto an insulating substrate so that, differently from conventional electrochemical impedance spectroscopy experiments, here the electrode in-plane conductivity is measured. Moreover, this method allows for distinguishing the ionic part of the in-plane electrode impedance from the electronic part that appears at high and low frequencies, respectively.In this work, in-plane electronic and ionic transport properties of porous carbon (YP50F) and MXene (Ti3C2) electrode are studied while being fully charged or. During polarization, both the ionic and electronic percolation change with the applied potential for both electrode, that could be associated with electrode volume and conductivity change under potential and/or because of some doping caused by ionic specific electrosorption. This operando in-plane impedance measurement method furthers the fundamental understanding of ionic and electronic transport properties and may turn out to be effective tool to improve the electrochemical performances of capacitive, pseudocapacitive, or battery-like electrodes.