Cheap Electrode Research Articles

A Low-Cost Zn-Ion Hybrid Supercapacitors with High Energy Density

In recent years, hybrid supercapacitors with greater potential and improved energy density have been completed by combining some battery and supercapacitor type electrodes. According to some researchers’ research, “hybrid” supercapacitor systems are technically “asymmetric” supercapacitor systems since they are built on two separate supercapacitor type electrodes. The primary aim behind the development of a hybrid capacitor (HC) is to improve the energy density or specific energy of the device, which will significantly boost the storage property. Moreover, the use of an electrical double layer capacitor type electrode provides a large surface area, improving the electrode/electrolyte interaction region, and helps in the fast ion-adsorption process, which prevents the degradation of the battery-type electrode due to repeated charge-discharge cycles. A suitable combination of specific power (due to the EDLC electrode) and specific energy (due to the faradic electrode) could drastically enhance the stability and longevity of the hybrid supercapacitor device. The di/tri-valent metal ion (Mg2+, Zn2+, Ca2+, Al3+, etc.) hybrid capacitors have garnered considerable attention in recent years owing to their potential cost benefit and application in stationary storage systems, whose development is crucial for the mass-scale penetration of renewable energy technologies.Zinc‐ion hybrid supercapacitors (ZIHSs) may be the most promising energy storage device alternatives for portable and large‐scale electronic devices, as they combine the benefits of both supercapacitors and zinc‐ion batteries. ZIHSs are mostly based on battery-type Zn metal as an anode and physical adsorption-based carbon materials as the cathode. Porous carbon materials with high surface area, good electrochemical stability, low cost, high electronic conductivity and tuneable surface structure are deemed as promising cathode materials for ZIHSs. It is generally recognized that the micropores facilitate electrochemical energy storage, and mesopores can effectively reduce the ion diffusion distance and transport resistance. Therefore, the adjustment and optimization of porous carbons electrodes are of great significance to ZIHSs.This work provides some insight into the strategy for designing effective non-aqueous and aqueous Zn-ion hybrid supercapacitors. Electrochemical characteristics of Zn-ion hybrid supercapacitor cells based on non-aqueous 1 M acetonitrile (AN) or propylene carbonate (PC) electrolytes with addition Zn(BF4)2, zinc di[bis(trifluoromethylsulfonyl)imide] (Zn(TFSI)2) and zinc trifluoromethanesulfonate (Zn(OTf)2) have been studied. Very high energy and power densities (80 Wh kg−1 and 21.2 kW kg−1) have been measured for 1 M Zn(BF4)2/AN based Zn-ion based hybrid supercapacitors (Fig. 1a). Very good stability during 3,000 cycles of cells has been achieved demonstrating reasonably high energy efficiency value (66.8%) for Zn(TFSI)2/AN based ZIHS cell, decreasing in the order of electrolytes: Zn(TFSI)2/AN > Zn(BF4)2/PC > Zn(TFSI)2/PC > Zn(OTf)2/AN > Zn(BF4)2/AN. Some assembled ZIHSs had shown excellent cycling and energy stability over 20,000 cycles [1].Electrochemical behaviour of Zn cation based salts in various aqueous electrolytes (ZnSO4, Zn(BF4)2, Zn(TFSI)2, and Zn(OTf)2) has been studied in thin ZIHS cell and compared with Zn(ClO4)2 aqueous electrolyte based cell electrochemical characteristics. At moderate specific power value (10 kW kg− 1) noticeable decrease of specific energy has been established in the order of aqueous electrolytes: Zn(ClO4)2 ⩾ Zn(BF4)2 > Zn(OTf)2 > Zn(TFSI)2 > ZnSO4 (Fig. 1b). The stability of Zn-ion hybrid supercapacitor cells under study in aqueous electrolyte solutions has been tested using the long lasting (up to 10,000 cycles) constant current charge/discharge method and very good stability for Zn(OTf)2, Zn(ClO4)2 and ZnSO4 has been observed [2,3].Taking into account the cheap and environmental friendliness electrodes and electrolyte used, the results can be applied for assembling of the cheap high energy density hybrid supercapacitors for sustainable energy storage/recuperation complexes, combined with photovoltaic fields and/or wind electricity generating systems. Acknowledgements This work was supported by the Estonian Ministry of Education and Research (TK210, Centre of Excellence in Sustainable Green Hydrogen and Energy Technologies), Personal Research Grant PRG676 and R&D project EAG228. The experimental part of the research was partially co-funded by the Feasibility Fund of the University of Tartu Development Fund.

Electrochemical Regioselective C(sp2)-H Bond Chalcogenation of Pyrazolo[1,5-a]pyrimidines via Radical Cross-Coupling at Room Temperature.

Herein, we disclose an electrochemical approach for the C(sp2)-H chalcogenation of pyrazolo[1,5-a]pyrimidines. This technique offers an oxidant and catalyst-free protocol for achieving regioselective chalcogenation of pyrazolo[1,5-a]pyrimidines. The procedure uses only 0.5 equiv. of diaryl chalcogenides which underscores the atom economy of the protocol. Key attributes of this methodology include mild reaction conditions, short reaction time, utilization of cheap electrode materials, and eco-friendly reaction conditions. Cyclic voltammetry studies and radical quenching experiments revealed a radical cross-coupling pathway for the reaction mechanism.

Early detection of the ovarian cancer with a label-free and disposable ITO-PET based immunosensor platform

Alpha fetoprotein (AFP), a popular biomarker for ovarian cancer, was the target of this studyto create an immunosensor based on electrochemical impedance spectroscopy (EIS). For this purpose, a disposable Indium tin oxide coated PET (In2O3/SnO2, ITO-PET) electrode was used as a basic electrode for working of the triple electrode system and the electrodes were modified with 3-(Trimethoxy silyl) propyl methacrylate (3- TMSPM) silanization agent. Although there are studies on the determination of AFP, the determination of AFP with a cheap, flexible and sensitive electrode system such as ITO-PET in this study makes the study remarkable. With the designed biosensors, AFP protein determination at a wide concentration range (0.05 pg/mL-100 pg/mL) could be successfully performed. To prove that the designed immunosensor was constructed correctly, linear range, repeatability, reproducibility and regeneration capacity (characterization studies) were investigated. Obtaining successful results in the storage capacity studies of the biosensor, which has high reproducibility and repeatability, showed that it also has potential for commercial use. The high specificity of the biosensor also proves its reliability. Finally, the performance of the biosensor in commercial human serum samples was also evaluated.

Electroreductive Cross‐Electrophile Coupling of Aromatic Carbonyl Compounds and Alkyl Bromides

AbstractClassical methods for the synthesis of tertiary alcohols mainly rely on the nucleophilic addition of organometallic reagents to carbonyl compounds. Here, we disclose a strategy for synthesizing tertiary alcohols via electroreductive cross‐electrophile coupling of aromatic carbonyl compounds and alkyl bromides (allyl, propargyl, benzyl and cyclohexyl bromides). This procedure features good substrate tolerance and friendly conditions (undivided cell, cheap and reusable carbon electrodes, reaction in open air, room temperature, without any external transition metal/activating reagent). Using this method, 32 desired products can be obtained with moderate to good yields, and gram‐scale synthesis is feasible, demonstrating the practicality of this approach.

Interface construction of Ni(OH)2/Fe3O4 heterostructure decorating in-situ defected graphite felt for enhanced overall water splitting

There is a persistent need to design efficient and cheap electrode materials for water electrolysis. Herein, a hierarchical Ni(OH)2/Fe3O4/graphite felt (GF) (NFGF) heterostructure bifunctional electrocatalyst is tailor-designed to accelerate the water splitting process via boosting the heterostructure interfaces. A facile electrochemical method is probed to synthesize NFGF heterostructure with in-situ GF surface functionalization. Various analyses are used to demonstrate the GF in-situ surface functionalization and interface engineering. Remarkably, NFGF displays boosted hydrogen and oxygen evolution reactions by presenting a low overpotential of −50 mV and 281 mV at a current density of 10 mA cm−2 and 30 mA cm−2, respectively. Thus, NFGF is tested as a bifunctional electrocatalyst in the two-electrode cell and demonstrates a low cell voltage of 1.55 V at a current density of 10 mA cm−2 with outstanding performance over a long time of electrolysis up to 24 h.

N, P co-doped microporous carbon derived from the central part of corn cob for high-performance symmetrical supercapacitors

A kind of N, P co-doped carbon material containing only micropores was prepared from the central part of corn cob. The effect of activation temperature on product structure and capacitive properties was studied in detail. The characterization results show that the carbon material (NPCC-650) prepared at 650 °C has high content of heteroatoms, large specific surface area and abundant micropores. Due to the structural advantages of NPCC-650, electrochemical tests show that the specific capacitance and rate properties of NPCC-650 are significantly better than the samples prepared at 550 °C and 750 °C. In addition, the symmetric supercapacitor assembled based on NPCC-650 has a specific capacitance of 45.8 F g−1 at a current density of 0.5 A g−1, corresponding to the energy density of 12.5 Wh kg−1. This research not only provides a method for the high value-added utilization of agricultural waste, but also provides an idea for the preparation of cheap and high-performance micropore carbon-based electrodes.

α-Fe2O3/, Co3O4/, and CoFe2O4/MWCNTs/Ionic Liquid Nanocomposites as High-Performance Electrocatalysts for the Electrocatalytic Hydrogen Evolution Reaction in a Neutral Medium.

Transition metal oxides are a great alternative to less expensive hydrogen evolution reaction (HER) catalysts. However, the lack of conductivity of these materials requires a conductor material to support them and improve the activity toward HER. On the other hand, carbon paste electrodes result in a versatile and cheap electrode with good activity and conductivity in electrocatalytic hydrogen production, especially when the carbonaceous material is agglomerated with ionic liquids. In the present work, an electrode composed of multi-walled carbon nanotubes (MWCNTs) and cobalt ferrite oxide (CoFe2O4) was prepared. These compounds were included on an electrode agglomerated with the ionic liquid N-octylpyridinium hexafluorophosphate (IL) to obtain the modified CoFe2O4/MWCNTs/IL nanocomposite electrode. To evaluate the behavior of each metal of the bimetallic oxide, this compound was compared to the behavior of MWCNTs/IL where a single monometallic iron or cobalt oxides were included (i.e., α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL). The synthesis of the oxides has been characterized by X-ray diffraction (XRD), RAMAN spectroscopy, and field emission scanning electronic microscopy (FE-SEM), corroborating the nanometric character and the structure of the compounds. The CoFe2O4/MWCNTs/IL nanocomposite system presents excellent electrocatalytic activity toward HER with an onset potential of -270 mV vs. RHE, evidencing an increase in activity compared to monometallic oxides and exhibiting onset potentials of -530 mV and -540 mV for α-Fe2O3/MWCNTs/IL and Co3O4/MWCNTs/IL, respectively. Finally, the system studied presents excellent stability during the 5 h of electrolysis, producing 132 μmol cm-2 h-1 of hydrogen gas.

A Sustainable and Cost-Effective Nitrogen-Doped Three-Dimensional Porous Carbon for High-Performance Lithium-Sulfur Batteries.

Affordable clean energy is one of the major sustainable development goals that can transform our world. At present, researchers are working to develop cheap electrode materials to develop energy storage devices, the Lithium-sulfur (Li-S) battery is considered a promising energy storage device owing to its excellent theoretical specific capacity and energy density. Herein, utilizing the ramie degumming waste liquid as raw materials, after freeze-drying and high-temperature calcination, a sustainable and cost-effective three-dimensional (3D) porous nitrogen-doped ramie carbon (N-RC) was synthesized. The N-RC calcined at 800 °C (N-RC-800) shows a superior high specific surface area of 1491.85 m2 ⋅ g-1 and a notable high pore volume of 0.90 cm3 ⋅ g-1. When employed as a sulfur host, the S@N-RC-800 cathode illustrates excellent initial discharge capacity (1120.6 mAh ⋅ g-1) and maintains a reversible capacity of 625.4 mAh ⋅ g-1 after 500 cycles at 1 C. Simultaneously, the S@N-RC-800 cathode also shows excellent coulombic efficiency and ideal rate performance. Such exceptional electrochemical performance of S@N-RC-800 can be primarily attributable to N-RC's high specific surface area, high porosity, and abundant polar functional groups. This green and low-cost synthesis strategy offers a new avenue for harnessing the potential of waste biomass in the context of clean energy storage.

Graphite counter electrode modified Tropaeolin‐O photo‐sensitized photogalvanic cells for solar power and storage

AbstractAn optimization, photo‐stability, and hysteresis property of the Graphite counter electrode‐modified Tropaeolin‐O (TPO) photo‐sensitized photogalvanic (PG) cells has been investigated. A complex H‐shaped cell design, a costly and delicate saturated calomel electrode (counter electrode), and a heavy sensitizer molecule (dye having high molecular weight, low diffusivity, and low photo‐stability) have been exploited for fabricating most of the PG cells so far. All these factors are not suitable for the fabrication of durable and cheap PG cells. Therefore, in the present study, the highly conductive/catalytically active robust graphite electrode with TPO dye photosensitizer (having a low molecular weight, higher diffusivity, and higher photo‐stability) has been exploited with diffusion‐friendly low cost and a simple transparent cylindrical glass tube. The cheap and robust graphite counter electrode has been exploited for optimization and long‐term study of the TPO photo‐sensitized PG cells. The observed electrical output is potential 676 mV, current 2000 µA, and power 340.0 μW. The power, current, and efficiency, have been found quite independent of the illumination window size. The potential and current have been observed to be quite stable over a long time during illumination, and the same has been supported by the hysteresis study.

A NEW APPROACH TO CONTROL DIABETES BY CONVERTING EXCESS BLOOD SUGAR TO ENERGY OVER ELECTROCATALYTIC METALLIC ANODE

Diabetes Mellitus, or Diabetes in short, is a group of widespread endocrine diseases characterized by high blood sugar levels. This research paper attempts to find a solution to this high sugar problem, by taking the route of electrochemistry. It was attempted to demonstrate that the excess sugar (glucose) in the bloodstream of a diabetic patient can be lowered by electro-oxidizing the excess sugar in Simulated Body Fluid (SBF) and convert it into electrical energy. For this, a sugar level detection system was developed, using a linear regression model with a coefficient of determination (R2 value) of 0.974. At first, one of the most popular as well as costly electrocatalytic materials i.e., Platinum was used to electro-oxidize the excess sugar. Upon its success, some highly electrocatalytic but cheap electrode materials were developed, such as Nickel, Nickel with nanocarbon, Manganese dioxide (MnO2) and Manganese dioxide with nanocarbon (MnO2C). And they also successfully electro-oxidized the excess glucose in SBF solution, thereby reducing the sugar levels. Thus, a potentially novel route to deal with the epidemic problem of diabetes has been proposed through this research work.

Catalyst-free electrochemical SNAr of electron-rich fluoroarenes using carboxylic acids

Herein, an electrochemically driven catalyst-free nucleophilic aromatic substitution (SNAr) of electron-rich fluoroarenes with carboxylic acids as weak nucleophiles under mild conditions was reported. A series of highly valuable ester derivatives were obtained in a direct and rapid way. This transformation features commercially available reagents and an exceptionally broad substrate scope with good functional group tolerance, using cheap and abundant electrodes and completed within a short reaction time. Gram-scale synthesis and complex biorelevant compounds ligation further highlighted the potential utility of the methodology. The mechanistic investigations and density functional theory (DFT) calculations verified the feasibility of the proposed pathway of this transformation.

Preparation and Characterization of Alkali Activated Carbon Based Theobroma Cocoa Pods: Application for Electrochemical Determination of Xanthine in Fresh Fish Sample

AbstractIn order to propose an alternative for the sensors made with complex materials, a cheap and facile electrode material based on the preparation of activated carbon from cocoa pods (Theobroma cacao) has been proposed for the electroanalysis of xanthine (Xa). Raw cocoa pods (RCP) and activated carbon cocoa pods (ACCP) were prepared and characterized by pH at the zero point of charge, FTIR, SEM/SEM‐mappings, EDX, XRD, Raman spectroscopy, BET/BJH analysis, 13C NMR, and TGA/DSC. RCP and ACCP were drop coated on the surface of a glassy carbon electrode (GCE) and characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The electrodes GCE/RCP and GCE/ACCP were used through differential pulse voltammetry to optimize the different parameters that can affect the determination of Xa and a calibration curve has been plotted in the range from 1.0 to 12.0 μM, leading to a detection limit of 0.264 μM. The interference, reproducibility, and stability were evaluated and the sensor was successfully applied in fresh fish sample. Therefore, the simple way of preparation of ACCP and the significant role played by GCE/ACCP in resolving the oxidation of Xa is expected to impact significantly the future sensor research through substitution of the costly and hazardous materials.

Effect and mechanism of PEDOT-Cu/Cu2O on the electrochemical reduction of nitrate with carbon electrodes

Electrochemical nitrate reduction for ammonia nitrogen (NH4+-N) generation is a promising method for resources recycling and relies on cheap and stable electrodes. In this study, carbon plate (CP), carbon felt (CF), and carbon brush (CB) were compared to identify their potential value on electrochemical nitrate reduction. By using the electrodeposition technique, copper-based nanometallic particles (Cu/Cu2O NPs) and poly-3,4-ethylenedioxythiophene (PEDOT) were loaded on the carbon substrates to prepare the (Cu/Cu2O) NPs/PEDOT/(Cu/Cu2O) NPs/CF electrode, which was tested in a single chamber electrolytic cell and subjected to continuous electrolysis of artificial wastewater (25–100 mg L−1 NO3--N) for 12 h. At a current density of 30 mA cm−2, the electrode achieved 97% nitrate removal and 81% NH4+-N selectivity. The synergistic catalytic interaction between Cu/Cu2O NPs and PEDOT improved the electrode reduction activity and NH4+-N selectivity, and had a good H* providing ability as noble metals. This provides a new method for nitrate reduction and NH4+-N recovery.

RuO2 Catalysts for Electrocatalytic Oxygen Evolution in Acidic Media: Mechanism, Activity Promotion Strategy and Research Progress.

Proton Exchange Membrane Water Electrolysis (PEMWE) under acidic conditions outperforms alkaline water electrolysis in terms of less resistance loss, higher current density, and higher produced hydrogen purity, which make it more economical in long-term applications. However, the efficiency of PEMWE is severely limited by the slow kinetics of anodic oxygen evolution reaction (OER), poor catalyst stability, and high cost. Therefore, researchers in the past decade have made great efforts to explore cheap, efficient, and stable electrode materials. Among them, the RuO2 electrocatalyst has been proved to be a major promising alternative to Ir-based catalysts and the most promising OER catalyst owing to its excellent electrocatalytic activity and high pH adaptability. In this review, we elaborate two reaction mechanisms of OER (lattice oxygen mechanism and adsorbate evolution mechanism), comprehensively summarize and discuss the recently reported RuO2-based OER electrocatalysts under acidic conditions, and propose many advanced modification strategies to further improve the activity and stability of RuO2-based electrocatalytic OER. Finally, we provide suggestions for overcoming the challenges faced by RuO2 electrocatalysts in practical applications and make prospects for future research. This review provides perspectives and guidance for the rational design of highly active and stable acidic OER electrocatalysts based on PEMWE.

An Electrical Resistance Diagnostic for Conductivity Monitoring in Laser Powder Bed Fusion.

With the growing interest in metal additive manufacturing using laser powder bed fusion (LPBF), there is a need for advanced in-situ nondestructive evaluation (NDE) methods that can dynamically monitor manufacturing process-related variations, that can be used as a feedback mechanism to further improve the manufacturing process, leading to parts with improved microstructural properties and mechanical properties. Current NDE techniques either lack sensitivity beyond build layer, are costly or time-consuming, or are not compatible for in-situ integration. In this research, we develop an electrical resistance diagnostic for in-situ monitoring of powder fused regions during laser powder bed fusion printing. The technique relies on injecting current into the build plate and detecting voltage differences from conductive variations during printing using a simple, cheap four-point electrode array directly connected to the build plate. A computational model will be utilized to determine sensitivities of the approach, and preliminary experiments will be performed during the printing process to test the overall approach.

SYNTHESIS, CHARACTERIZATION AND SENSING BEHAVIOUR OF POLY(ACRYLAMIDE-CO-AMPS) AND POLY(ACRYLAMIDE-CO-AMPS)/POLYANILINE HYDROGELS USING PENCIL GRAPHITE ELECTRODES

The copolymer samples composed of acrylamide with different amounts of 2-acrylamido-2-methylpropane sulfonic acid and aniline were synthesized with a cross-linker N, N’-methylene bisacrylamide and an initiator potassium per sulfate by a free radical copolymerization method. Cheap and disposable pencil graphite electrodes were developed by surface modification with hydrogel polymer coating. The sensing property of the electrodes was characterized by cyclic voltammetry, differential pulse voltammetry, and square wave voltammetry. The molecular structure of the hydrogel polymers was characterized by FT-IR spectroscopy. The morphology of the resulting hydrogels was studied by SEM and X-ray diffraction. The sensing properties of the hydrogel polymer-coated electrodes were tested in different concentrations of methylene blue in deionized water with variable dipping times of the electrodes. The cyclic voltammetric characterizations of a copolymer of aniline with the hydrogels coated pencil graphite electrodes showed higher sensing response to methylene blue dye.

An anti-electrowetting carbon film electrode with self-sustained aeration for industrial H2O2 electrosynthesis

A novel concept of an anti-electrowetting carbon film electrode with self-sustained aeration was devised and demonstrated to develop next-generation cheap and scalable metal-free electrodes for industry-scale H2O2 electrosynthesis.

Amine-Functionalized Pencil Graphite Electrode for Simultaneous Determination of Dopamine and Uric Acid

In this study, an electrochemical transducer based on an Amine-functionalized cheap and disposable pencil graphite electrode (NPGE) is proposed for the simultaneous monitoring of Dopamine (DA) and Uric Acid (UA) in biological samples such as serum and urine. The prepared NPGE was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It was found that the incorporation of amine groups significantly improved catalytic activity than the bare pencil graphite electrode (BPGE). Moreover, the electrode modification parameters and effects of different analytical variables such as sweep rate, pH of the supporting electrolyte solution, and possible interfering ions or molecules in quantification were optimized using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimized conditions, DA and UA oxidation currents showed linear responses over the concentration range of 1.06-160 µM for DA and 30.06-150 µM for UA. The limit of detection (LOD) for DA and UA were estimated to be 0.94 and 1.26 µM, respectively. In addition, the transducer’s sensitivity of 5.47 µA.µM-1cm-2 for DA and 1.70 µA.µM-1cm-2 for UA were calculated. Aiming to reuse the transducer, a regeneration solution is proposed which could successfully remove the adsorbed oxidized products from the surface. Finally, the developed transducer’s performance was compared with the established clinical method. Figure 1

Developing Hybrid Aqueous Li/Na-Ion Capacitors by Electrodes Synthesized by Facile Recycling and Reuse Process: Waste to Wealth

The explosive evolution of industrialization and technologies has grabbed eyeball attention inthe current scenario for improving the living standard of the human beings irrespective of the threat and risk possessed by the environment. So to overcome this catastrophe, there has been a significant focus on progressive development of electrochemical energy storage and conversion systems to resolve the intermittency nature of renewable energy sources. The electrochemical energy storage devices such as batteries and supercapacitors have been relied upon the ability to store the charge in the wide potential region with high Coulombic efficiency and long-term stability. However, transition metal oxides are well known, for their high theoretical specific capacity but suffer from low electronic conduction and capacity fading during cycling. To address these shortfalls metal oxides are usually, embedded within a conductive carbon-based matrix (for instance graphene). The use of graphene would afford easy pathway for electron movement and increases the surface area for higher interaction of active electrode materials with electrolyte. Subsequently, graphene based transition metal oxides composites have attracted active research pursuits in synthesizing the low cost effective electrode materials for energy storage devices. And if graphene is recycled and reused then it’s very much cheap and efficient electrodes for hybrid energy storage devices. In this work, electrode materials are developed by facile and economic approach with an aim to achieve improved electrochemical activity. The conversion of utilized electrode materials (e-waste) to efficient graphene electrodes (wealth) is validated in this research. The challenges in this work are (i) recycling pure samples, (ii) resynthesizing the graphene and tuning its layers, (iii) stability and efficiency of electrode materials, (iv) optimization of electrode materials and (v) practical demonstration of hybrid-ion capacitors. The fascinating part of the research finding is both the electrode materials are derived via. recycling, for which device can be promise to be sustainable and clean energy. The details will be presented in ECS conference. Such scheme could serve as precedent to the development of potential electrode materials for energy storage devices.

Insights into the Electrochemical Degradation of Aluminum Dual-Ion Batteries: Influence of Internal Cell Resistance & Applied Current Density

To face the upcoming demand on high-power energy storage systems, e.g, for high-dynamic grid-stabilization , stationary devices as used in photovoltaics, and mobile applications led to invention of various battery technologies like sodium-ion batteries (SIB), zinc-ion batteries (ZIB) and high-power lithium-ion batteries (LIBs). Especially the several lithium-ion battery technologies have in common that currently used raw materials like lithium-salts and heavy metals (Ni, Co, Mn) are becoming increasingly scarce and therefore expensive. Without substitution by less-critical materials the ongoing energy system transformation cannot be successfully achieved.One promising system that gained attention in the last few years is the so-called aluminum graphite dual-ion battery (AGDIB). The active electrodes are made of cheap and abundant materials like graphite as cathode material and an aluminum-foil as anode1. During operation chloroaluminate anions from the electrolyte, which is currently based on ionic liquids like 1-ethyl-3-methylimidazoliumchloride ([EMIm]Cl) and AlCl3 in stoichiometric ratios as well as deep-eutectic solvents based on mixtures of urea and AlCl3, are (de)intercalated in the graphitic host-structure while on the anode metallic aluminum is electrochemically deposited and dissolved see equation (1) and (2), respectively2, 3. The overall mechanism is quite comparable with Li-metal batteries, where metallic Li is reversibly dissolved and deposited.The big advantages of AGDIBs are cheap electrode materials (graphite & aluminum), electrolytes based on urea and an extraordinary high-power cell-chemistry. Recent publications showed charging rates up to 20 A g-1 Graphite equal to 9 kW kg-1 Graphite in laboratory-scaled cells. Also, the lifetime of those batteries seems to be non-competitive, cycles up to half a million were reported with negligible capacity fading or degradation effects.4 To develop scalable and more representative battery cells, we established the AGDIB cell chemistry in a new corrosion-stable pouch bag design. Due to the significant increased electrode surface area and overall capacity, hitherto unknown effects were observed which limited the end of lifetime (EOL) of those batteries to less than 8,000 cycles. Herein, we report on a detailed analysis of the cell failure, including several electrochemical in-situ techniques like galvanostatic intermittent titration techniques (GITT), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV).5 The obtained data will allow a fundamental understanding of the cell operation under low (≤ 1 C-rates) and very high C-rates ≥ 15 C, which is important for establishing a durable AGDIB with high cycling stability.References M.-C. Lin, M. Gong, B. Lu, Y. Wu, D.-Y. Wang, M. Guan, M. Angell, C. Chen, J. Yang, B.-J. Hwang and H. Dai, Nature, 520(7547), 325–328 (2015). M. L. Agiorgousis, Y.-Y. Sun and S. Zhang, ACS Energy Lett., 2(3), 689–693 (2017). M. Angell, G. Zhu, M.‐C. Lin, Y. Rong and H. Dai, Adv. Funct. Mater., 30(4), 1901928 (2020). G. A. Elia, N. A. Kyeremateng, K. Marquardt and R. Hahn, Batteries & Supercaps, 2, 83–90 (2019).M. Safari and C. Delacourt, J. Electrochem. Soc., 158(10), A1123 (2011). Figure 1