Secondary Alkaline Research Articles

Indicators for Optical Analysis of Local Conditions in Bifunctional Air Electrodes

Introduction Bifunctional air electrodes using aqueous alkaline solutions have attracted increasing attention as positive electrodes for metal-air secondary batteries and alkaline regenerative fuel cells, which have the advantages of high capacity and high safety. However, the large overpotential for the reaction in bifunctional air electrodes impedes their practical application. In order to reduce the overpotential, it is necessary to design electrodes based on an understanding of the reaction field in the electrodes since the favorable reaction fields for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are different [1]. Our research group has developed an operando measurement system using confocal optical microscope to visualize the local conditions of electrodes during the battery operation [2, 3] and has succeeded in visualizing the local state of charge in a LiFePO4 composite electrode from the brightness [2]. Though operando measurement system using a confocal microscope have the advantage of high versatility, high accessibility and sufficient time or spatial resolution, its application to bifunctional air electrode has not been reported. One of the challenges in visualizing the local conditions in bifunctional air electrodes is the absence of clear color changes corresponding to the local conditions. In this study, we searched for indicators to optically visualize local conditions in bifunctional air electrodes. The optical properties of the candidate indicators were evaluated by using a confocal microscope. Experimental Ag and Ni were selected as candidate indicators for visualizing local potential since they undergo redox reactions at around the potential for OER in alkaline electrolytes. A three-electrode cell for operando optical observation was constructed using metal foils of the candidate materials as the working electrode, Ni mesh as the counter electrode, Hg/HgO as the reference electrode, and 8 mol dm–3 KOH solution as electrolyte. Constant potential measurements were conducted at around the potential range of OER. At the same time, the optical changes of the working electrode were observed with a confocal microscope (ECCS, Lasertec) to evaluate their optical properties as potential indicators. Results and discussion Fig. 1 shows the applied potentials and the normalized red and blue signal outputs of the Ag and Ni foil electrodes. The potentials are written in terms of RHE. As for the Ag foil, the red signal output decreased significantly with a potential step from 1.18 V to 1.23 V during oxidation, and the red signal output increased significantly with a potential step from 1.18 V to 1.13 V during reduction. This significant output change corresponds to the redox reaction of Ag/Ag2O. Regarding the Ni foil, the blue signal output decreased with a potential step from 1.38 V to 1.43 V during oxidation, and the blue signal output increased in multiple steps from 1.43 V to 1.23 V during reduction. This signal output change corresponds to the redox reaction of Ni(OH)2/NiOOH. These results indicate that Ag and Ni foils can be used as the local potential indicators for OER. The pH and oxygen partial pressure dependencies will also be reported at the site. Acknowledgments This work was financially supported by JST PRESTO and JRP-LEAD with DFG (JPJSJRP20221602).

Health hazards from perchlorate enriched groundwater of a semi-arid river basin of south India and suggesting in-situ remediation through Managed Aquifer Recharge

The present study was conducted to assess the groundwater quality and perchlorate contents in the pre- and post-monsoon groundwater samples along with its associated health concerns with suggesting in-situ remediation in semi-arid Arjunanadi River basin of south India. Most of the samples (86 in pre-monsoon and 84 in post-monsoon out of total 94) showed secondary salinity and secondary alkalinity, and the perchlorate showed positive relations with Na+, K+, SO42-, Cl-, and NO3- contents. The main source of perchlorate could be fireworks manufacturing industries with 23 % of pre-monsoon (246.5 km2) and 33 % of post-monsoon samples (360 km2) showing perchlorate above the World Health Organization (WHO) standard (>0.07 mg/l). Perchlorate health risk assessment (PHRA) and total hazard index (THI) indicated more effect from oral pathway compared to the dermal pathway with about 80 %, 79 %, 65 %, and 60 % of samples causing health complications for infants, children, women, and men during the pre-monsoon. The post-monsoon groundwater showed increased health risks with 90 %, 82 %, 74 %, and 69 % of samples remaining hazardous for infants, children, women, and men. Artificial recharge through Managed Aquifer Recharge (MAR) techniques in the high-risk area could be useful to minimize the perchlorate contamination in groundwater and associated health risks under the United Nations Development Programme (UNDP) Sustainable Development Goals 3 and 6 (SDGs) for a healthy society.

Optimization of Bi2O3 Content in CuO-Bi2O3 Cathodes for Secondary Zn Alkaline Batteries Leads to Improved Capacity and Cycling

Secondary alkaline batteries pairing Zn anodes with metal oxide cathodes (MnO2, CuO, etc.) are a promising route to energy-dense, inexpensive batteries for use in grid-scale energy storage. However, the low cycle life and material stability of secondary alkaline batteries, especially when compared to competing chemistries like Li-ion batteries, must be addressed in order to further develop these technologies. In recent years, studies have shown that the addition of chemical additives like Bi2O3 to the metal oxide cathodes can significantly improve their cyclability. Further work is needed, however, to better understand the mechanism of this improvement and further optimize cathode composition and performance.In this presentation, we will present our efforts to optimize the Bi2O3 composition of a CuO-Bi2O3 cathode for use in secondary Zn-CuO alkaline batteries. Earlier reports showed that relatively large quantities of Bi2O3 additive (10 wt.%) allowed for improved cathode conductivity and promoted the electroreduction of CuOx to Cu0. However, the use of such large quantities of a heavy additive also reduced the effective capacity of the resulting cathode by up to 15%, relative to a CuO cathode without any Bi2O3. Here, we show that the use of as little as 1 wt.% Bi2O3 is sufficient to affect a similar improvement in CuO cycling performance, and that even a Bi2O3-saturated KOH electrolyte solution is sufficient to impact the cyclability of a CuO cathode. Using a variety of physical and (electro)chemical techniques, we show that at these low Bi concentrations the Bi likely cycles between a sparingly soluble BiOx/Bi(OH)4 2- reservoir contained in both the cathode and electrolyte in the charged state, and solid Bi0 that is uniformly distributed on the surface of the CuOx/Cu0 cathode in the discharged state. Various electron microscopy techniques (SEM and STEM) show that this has a notable impact on the physical morphology of the active material in the cathodes after cycling, while electrochemical impedance spectroscopy (EIS) shows how electron transfer resistance varies based on Bi2O3 concentration. On a fundamental level, our results show that changes in Bi2O3 concentration notably impact the charge-discharge behavior of the CuO cathodes and results in the suppression of metal hydroxide-related redox peaks on charge. The absence of these peaks is thus correlated with improved cyclability, suggesting that the addition of Bi and the suppression of these recharge pathways may lead to higher capacity, more stable CuO cathodes in the future.This work was supported by the U.S. Department of Energy, Office of Electricity and Sandia National Laboratories, a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Dr. Imre Gyuk, Director of Energy Storage Research, Office of Electricity is thanked for his financial support. The views expressed herein do not necessarily represent the views of the U.S. Department of Energy or the United States Government.

Enhancing Secondary Alkaline Battery Performance: Synthesis and Electrochemical Characterization of Zn Anodes, Based on ZnO@C Core‐Shell Nanoparticles

AbstractWhile alkaline Zn batteries, like traditional rechargeable aqueous batteries, boast an advantage in terms of energy density, their progress has been hampered by concerns related to the anode. These concerns include issues like Zn dendrites, self‐corrosion, passivation, shape change, and the hydrogen evolution reaction (HER). To tackle these challenges, we have introduced a nanostructuring approach for the anode, employing carbon‐coated ZnO nanoparticles (ZnO@C) as the active material. In this study, we synthesized ZnO@C nanoparticles in an environmentally sustainable and scalable manner to address passivation and dissolution issues jointly. Nanoscale ZnO particles effectively prevent passivation, while carbon shell slows down the dissolution of zincate. The Zn anode exhibits a significant performance boost when compared to Zn foil and bare ZnO nanoparticles, even when subjected to demanding conditions (without the use of ZnO‐saturated electrolyte). This rechargeable Zn anode marks a significant step toward the realization of practical, high‐energy rechargeable aqueous batteries, such as Zn‐air batteries.

(Invited) Experimental and Data Analysis Platforms to Better Understand the Corrosion and Discharge of Powdered Zn

Zinc anodes have been a cornerstone of many commercial and pre-commercial battery technologies including primary and secondary alkaline cells, Zn-air batteries and Zn-ion batteries. To maximize the performance of devices at both the lab and commercial scales, moderate surface area (mm-sized) Zn powder is used – either immobilized onto a diffusion electrode or incorporated into a slurry. Unlike nano-sized materials, micron-sized materials are poorly characterized by traditional electrochemical techniques like thin-film rotating disk electrodes, because the roughness introduced by the relatively large particles disrupts the ideal fluid flow near the surface, negating the mathematical description of the electrode behavior. This leads many researchers to try and characterize the Zn behavior in more application-like cells. The downside of doing this is that there is a strong influence of the counter electrode, electrolyte solution and the efficacy of the specific individual in assembling the cells. Therefore, there is a need to develop new platforms that have the ability to determine the electrochemical properties of powdered Zn – most notably achievable capacity and corrosion current – and to develop analytical models to describe their behavior.Over the past several years, our group has been developing new platforms to understand how Zn behaves during discharge and charge, including 1-D cells and cells that mimic the geometry of a primary alkaline battery [1]. However, those platforms have their limitations. In this talk, another new cell, coined the “gravity cell” will be discussed. The gravity cell has a small well where Zn (either as raw powder or in slurry form) is gravity deposited onto an indium foil current collector. Typically, a gel electrolyte is placed on top of the Zn bed, followed by liquid electrolyte, which also contains the counter and reference electrodes. The gravity cell is used to both discharge the Zn powder and to measure its corrosion characteristics. This can be done as a function of mass loading, which introduces limitations into the behavior as the Zn discharges from the Zn/gel interface towards the current collector. This type of discharge, limited by Ohmic resistance, requires new mathematical frameworks to extract the desired parameters. This talk will focus on the design of the cell as well as the derivation of the mathematical framework. Then, data will be shown using several types of Zn powder both in the presence and absence of surfactants that aim to reduce the corrosion rate.

Geology and Groundwater Quality Analysis for Clean Water and Irrigation of Sanga-sanga District, Kutai Kartanegara Regency, East Kalimantan Province

The research locations are in two sub-districts, namely Sanga-Sanga District, Samarinda City and Palaran District, Kutai Kartanegara, East Kalimantan Province The research method used in this study is geological mapping, then laboratory analysis. The well water sample data used is 2 sample water which is considered to represent the research area. Geological conditions in the study area there are 3 rock units where the rock units of the oldest are the Sanga-sanga sandstone unit, the Bantuas sandstone unit and alluvial deposits. For geomorphological units, it is divided into 6 forms, namely the eroded hill unit, the remaining hill, the Alluvial Plain, swamp, river body, disposal and mine opening. Based on the results of the piper diagram analysis Groundwater is included in the type of magnesium bicarbonate with carbonate hardness (secondary alkalinity) > 50% groundwater is dominated by alkaline soil (Ca + Mg) and weak acids (CO3 + HCO3), and based on the results of the stiff diagram analysis, the research area is included in the type of calcium carbonate (CaHCO3) and Magnesium Carbonate (MgHCO3). The assessment of groundwater quality for irrigation purposes concluded that the analyzed sample could be used as irrigation water.

Catalytic Oxidative Decomposition of Dimethyl Methyl Phosphonate over CuO/CeO2 Catalysts Prepared Using a Secondary Alkaline Hydrothermal Method

Bimetallic synergism plays an important role in lattice-doped catalysts. Therefore, lattice-doped bimetallic CuO/CeO2 catalysts were prepared by secondary alkaline hydrothermal reaction. During this process, the CeO2 nanomaterials were partially dissolved and recrystallized; thus, Cu ions were doped into the CeO2 lattice. The physical and chemical properties of CeO2, CuO/CeO2, and CuO were investigated. H2 temperature-programmed reduction characterization showed that the oxidation activity of CuO/CeO2 was significantly improved. X-ray photoelectron spectroscopy results showed that electron transfer occurred between Ce and Cu in the CuO/CeO2 catalyst. Additionally, Raman characterization confirmed the strong interaction between Cu and Ce. After CuO was loaded, the thermal catalytic decomposition performance of the catalyst was significantly improved with respect to the sarin simulant dimethyl methyl phosphonate (DMMP); with an increase in the Cu/Ce ratio, the performance first strengthened and then weakened. Additionally, the reaction tail gas and catalyst surface products were analyzed using mass spectrometry and ion chromatography, and the changes in the surface products during the thermal catalytic decomposition of DMMP were characterized at different temperatures using in situ diffuse reflectance infrared Fourier transform spectroscopy. Finally, the catalytic reaction pathways of DMMP on CeO2, CuO/CeO2, and CuO were inferred. The study results not only demonstrate an effective catalyst for the removal of nerve agent but also a feasible preparation method for lattice-doped bimetallic catalysts in the field of environmental protection.

Estimation of Discharge Capacities Using Generalized Peukert’s Equation for Saft Industrial Standby Batteries

Saft Industrial Standby (ISD) battery utilizes robust nickel-cadmium alkaline electrochemistry that delivers reliable performance and long life of at least 15 years over a wide range of temperature (-20 °C to 50 °C). The battery is designed with nickel based positive electrode and plastic bonded cadmium electrode in a vented prismatic cell. Typically, telecom applications used to require long duration backup power sources. With the advent of 4G/5G, the duration for backup power has been reduced to 1 hour or less. Therefore, new ISD battery was designed for power applications like 174 W/cell discharge for 1 hour and at the same time it can deliver high energy density up to 100 Wh/l. Additionally, low water consumption due to the high charge efficiency makes this battery ideal for the maintenance free remote installations. All these features render the battery aptly suitable for providing back-up power in telecom networks (4G and 5G) including remote cabinets at the lowest total cost of ownership.The ISD battery (Tel.X-Plus) is compliant to the Telecordia GR (Generic Requirement)-3020 CORE standard, which is recommended for the secondary alkaline batteries used in the telecom back-up application. This standard requires declaration of minimum 28 discharge currents entailing different durations and end voltages for a specific battery capacity. Hence, correct estimation of deliverable capacities for any definite duration and end voltage can reduce significant number of test trials. In addition, it helps sizing the battery for different power and energy installations. There are a few analytical techniques, such as Peukert’s and Shepherd’s equations that can be used to model the discharge characteristics of batteries. There are three different forms of generalized Peukert’s equations: algebraic, hyperbolic tangent and complementary error functions. In this study, to evaluate the discharge capacities we investigated the complementary error function of the generalized Peukert’s equations described in the equation 1: C= (Cm/erfc(-1/n)) * efrc(((i/ik)-1)/n) ... (1)where, C is the capacity of the battery during discharge, Cm is the highest discharge capacity, i is the discharge current, ik and n are statistical parameters. We know that phase transition is key to the discharge of a battery. Therefore, we selected the equation which also defines the phase transition process. The discharge capacities were calculated between 24-hour and 0.20-hour discharge durations for 1 V/cell, 1.05 V/cell, 1.10 V/cell and 1.14 V/cell end points using the equation 1. Here, the discharge capacity that was experimentally determined at the nominal C/24 rate was used as the maximum discharge capacity, Cm. The value of the statistical parameter n is within 0 and 1 to satisfy the capacity limits when discharge current tends to infinite and zero. For example, n equals to 0.6 is used for the calculations pertaining to the 180 Ah rated battery. The other statistical parameter ik was empirically selected for each end point voltage e.g., 250 A for 1.1 V/cell. Figure 1 shows the results for the calculated discharge capacities along with the experimental values at the 1.1 V/cell cut-off. The calculated numbers closely match with the experimentally obtained values with the r2 of 0.998 (Figure 1)Results for the other cut-off voltages (1.0 V/cell, 1.05 V/cell and 1.14 V/cell) were also obtained using the equation 1 and closely match the experimental values. Thus, the phase transition form of generalized Peukert’s equation (complementary error function) can be used for evaluating the capacities between 24-hour and 0.20-hour of discharge durations. Consequently, it enhances the test efficiency remarkably and sets the stage for battery sizing. Future studies include but not limited to the significance of n and ik, algebraic form of Peukert’s equation and Shepherd’s equation to understand the effectivity of each model with a focus on the discharge durations below 0.20-hour. Figure 1

Approaches Towards Improving Zinc-Nickel Batteries Performance

The zinc/nickel electrochemical system has long been proposed as a good candidate of secondary alkaline batteries due to its excellent performance versus other aqueous batteries, such as high practical specific energy, excellent specific power, high open circuit voltage, low cost and low toxicity [1,2]. These advantages make it suitable for replacing lead-acid and nickel-cadmium batteries [3]. However, the high solubility of zinc in concentrated alkaline electrolytes is still a significant problem that induces two main failure mechanisms: a shape-change of the zinc electrode and a redistribution of the zinc active material due to its dissolution/redeposition during cycling. Dendritic growth can occur as a consequence of zinc dissolution/redeposition, and if severe, may lead to separators’ perforation and internal electrical short-circuits [4]. These drawbacks reduce the cell's capacity and lifetime, especially compared to traditional competing systems [5]. In addition, since the hydrogen evolution reaction (HER) is thermodynamically possible (especially during charging), the coulombic efficiency of the zinc electrode can be lowered by this parasite reaction [6]. The undesirable HER consumes water and some of the active material, yielding zinc hydroxide which in turn can generate a passivation layer that lowers the usability of the zinc anode materials [7]. There are different approaches to overcome these problems, such as the integration of additives in the active material formulation and/or in the electrolyte.In this contribution, we will show how regeneration of the active material can be obtained via appropriate steps of rest submitted to the active material and without the need for additional energy input. The so-called “self-healing” of the active material allows to recover a substantial part of the electrochemical performance. The concept was deeply studied and monitored by scanning electron microscopy coupled with elemental mapping by X-ray energy dispersive spectrometry, and operando tomography. An increase in the coulombic efficiency has been demonstrated making this discovery very promising for the future of zinc-based alkaline batteries. Keywords: Zinc-nickel batteries, additives, self-healing

Phase-transition tailored nanoporous zinc metal electrodes for rechargeable alkaline zinc-nickel oxide hydroxide and zinc-air batteries

Secondary alkaline Zn batteries are cost-effective, safe, and energy-dense devices, but they are limited in rechargeability. Their short cycle life is caused by the transition between metallic Zn and ZnO, whose differences in electronic conductivity, chemical reactivity, and morphology undermine uniform electrochemical reactions and electrode structural stability. To circumvent these issues, here we propose an electrode design with bi-continuous metallic zinc nanoporous structures capable of stabilizing the electrochemical transition between metallic Zn and ZnO. In particular, via in situ optical microscopy and electrochemical impedance measurements, we demonstrate the kinetics-controlled structural evolution of Zn and ZnO. We also tested the electrochemical energy storage performance of the nanoporous zinc electrodes in alkaline zinc-nickel oxide hydroxide (NiOOH) and zinc-air (using Pt/C/IrO2-based air-electrodes) coin cell configurations. The Zn | |NiOOH cell delivers an areal capacity of 30 mAh/cm2 at 60% depth of discharging for 160 cycles, and the Zn | |Pt/C/IrO2 air cell demonstrates 80-hour stable operation in lean electrolyte condition.

Design of bifunctional air electrodes based on the reaction fields between oxygen reduction reaction and oxygen evolution reaction

Large overpotential is one of the critical issues of bifunctional air electrodes for metal–air secondary batteries and alkaline regenerative fuel cells. To overcome this problem, construction of gas diffusion electrodes providing plenty amount of reaction fields for oxygen reduction and evolution are necessary. In this work, we investigate the reaction fields in the gas diffusion electrodes by comparing the oxygen diffusion resistances in the gas diffusion electrodes with different electrolyte solutions and catalyst layer thicknesses to improve the overpotential of the gas diffusion electrode. It is suggested that the reaction fields for oxygen reduction and oxygen evolution concentrate on the air side and the electrolyte sides of the catalyst layer, respectively. Based on this assignment, we fabricate a gas diffusion electrode where the oxygen reduction and evolution catalysts are, respectively arranged to the air and electrolyte sides of the catalyst layer. This electrode showed both lower overpotential and higher cyclability than those loaded the same catalysts with the opposed and mixed configuration. This result verifies the assignment of the reaction fields and shows the impact of the catalyst arrangement on the activity and the durability of the bifunctional electrodes.

The Trade-Offs in the Design of Reversible Zinc Anodes for Secondary Alkaline Batteries

The Trade-Offs in the Design of Reversible Zinc Anodes for Secondary Alkaline Batteries

Hydrochemical Evolution of Groundwater in Dehui, China

Although Dehui City has excellent agricultural conditions, long-term large-scale over-cultivation and human activities in recent years have caused significant changes in the local groundwater chemical characteristics. This study analyzes the causes, evolution, and prediction of groundwater chemistry via multi-disciplinary theoretical cross-cutting methods, such as groundwater ion composition-ratio analysis and groundwater influencing factor analysis, and artificial neural networks. The lithological characteristics of the groundwater aquifer were combined with ion composition-ratio mapping to explore the cause of groundwater chemistry composition in the study area. Piper three-line diagrams and Gibbs diagrams were used to analyze the evolution characteristics and influencing factors of groundwater chemistry in the study area. Based on these data, time series predictions were made for hydrochemical data. The results demonstrate that the chemical origins of groundwater in the study area are mainly background stratum and cation exchange, influenced by human activities. The main factors of groundwater chemical characteristics have changed from rock weathering to evaporation/precipitation in the past two decades. The hydrochemical characteristics changed from secondary alkalinity to secondary salinity. The predicted data from long short-term memory neural networks indicated that groundwater would continue salinization without the changes in the conditions, leading to land degradation in the study area.

Suitability of spring water from the Upper Beas River Basin in Kullu Valley (Western Himalaya, India) for drinking and irrigation purposes

Spring water is a reliable source of potable water to many communities and habitants in western Himalayan region of India. The present study evaluates the hydrochemical nature of spring water using various drinking parameters and agricultural indices in upper Beas basin of Kullu Valley, Himachal Pradesh, India. Fifty springs were sampled for the estimation of physico-chemical parameters and major ions. The results indicate that majority of the spring waters in the study area are suitable for drinking as well as irrigation purposes except for few locations. About 14% of springs showed high nitrate content (45 to 92.6 mg/L) more than BIS permissible limit of 45 mg/L. The source of contamination could be sewage disposal, livestock waste and fertilizers. Fluoride (0.16–0.49 mg/L) was found to be within permissible limits for drinking. Drinking Water Quality Index ranges from 1.74 to 108, and Irrigation Water Quality Index ranges from 0.27 to 8.21. Both these indices indicate that the spring water falls in excellent to good category and is suitable in terms of potability and irrigation uses. Hydrogeochemical characteristics of the spring waters indicate that alkaline earths (Ca2+ + Mg2+) dominate alkalies (Na+ + K+) and strong acids (SO42− + Cl−) dominate weak acids (CO32− + HCO3−). Based on Piper’s classification, the spring water data falls in no cation–no anion dominant zone followed by carbonate hardness (secondary alkalinity) zone and hydrochemical trends (Piper’s and Gibb’s plots) inferred that spring water chemistry is mainly controlled by water rock interaction followed by rainwater chemistry.

Responses of seven strawberry cultivars to alkalinity stress under soilless culture system

Due to impact on the pH of growing medium, water alkalinity is the most important parameter determining water quality. Thus, to investigate the effect of sodium bicarbonate on strawberry, an experiment was carried out considering two factors including sodium bicarbonate at three levels (0, 15 and 30 mM) and seven strawberry cultivars (Albion, SanAndreas, Paros, Aromas, Diamante, QueenElisa, and Camarosa). Sodium bicarbonate increased the EC and pH of growing medium in all studied cultivars. The results showed that vegetative and reproductive growth, chlorophyll fluorescence parameters, and relative water content of leaves diminished with an increase in sodium bicarbonate concentration and Camarosa cultivar was more sensitive than other cultivars. The maximal quantum yield of PSII photochemistry (Fv/Fm), PI, Fv, Fm, Area, Fv/Fo, RC/ABS and (1-Vj)/Vj parameters declined in all cultivars with increasing sodium bicarbonate, especially in Camarosa cultivar. Fo parameter rose with increasing sodium bicarbonate, with the greatest increase being related to Camarosa cultivar at 30 mM sodium bicarbonate. The chemical/physical parameters of fruit diminished by bicarbonate, with the San Andreas and Diamante showing the highest and lowest fruit EC, pH, and TSS, respectively. Under stress conditions, Paros cultivar showed the minimum changes in fruit color parameters. The results showed that Paros and Camarosa are the most tolerant and sensitive cultivars to alkalinity stress, respectively. Also, chlorophyll fluorescence parameters, especially PI and Fo, are suitable indices for bicarbonate stress evaluation in strawberry cultivars and secondary alkalinity induced stress like salinity and drought stress may cause a change in PI and Fo.

Effects of hydrogen bubbles on deformation of zinc anodes at high depth of discharge

The effects of hydrogen evolution reaction on the deformation of zinc anode which cycles at nearly 100% depth of discharge (DOD) are studied. Results show that the generated hydrogen bubbles during charging process will gather on the surface of the middle of the anode and will cover the ZnO which is produced by the hydrolysis of Zn (OH)42− and prevent ZnO participation in the charging process. Since the charge-discharge reaction only occurs at the edges of the bubbles, the multiple dissolution and redeposition of the active material results in the formation of a massive ZnO and a very low specific discharge capacity. This finding provides a new perspective for the deformation of zinc anodes of the secondary alkaline zinc-based batteries.

Preparation and characterization of glass ceramic foams based on municipal solid waste incineration ashes using secondary aluminum ash as foaming agent

Glass ceramic foam with high strength was developed using municipal waste incineration bottom ash, fly ash, pickling sludge and secondary aluminum ash as raw materials without foaming agent. The effect of the secondary aluminum ash content and alkalinity on the pore morphology, porosity, water absorption, compression strength and bulk density of glass ceramic foams has been evaluated. The results showed that the increase of secondary aluminum ash content is beneficial to gas generation, but it will reduce the formation of liquid phase, resulting in the variation of pore morphology. In the process of alkalinity adjustment, the degree of polymerization of glass decreased first and then increased, which is similar to the change of max pore size, providing guidance for quantitative analysis of pore formation. The optimized sample reached porosities up to 63.02%, bulk density of ~1.42 g/cm3, and excellent compressive strength ~41.93 MPa. The analysis of self-foaming mechanism proved that secondary aluminum ash can be used as a self-foaming waste results from the oxidation reaction of AlN. In this work, a clean and sustainable utilization method has been proposed for recycling multiple solid wastes by preparing glass ceramic foams with a potential application for construction insulation materials with load-bearing. Moreover, an innovative exploration of secondary aluminum ash as the self-foaming waste in high temperature environmental was proposed.

The influence of copper and carbon black on electrochemical behavior of nickel positive electrode

Nickel hydroxide is used as an active material in positive electrodes of secondary alkaline batteries. In alkaline batteries, the capacity of the negative electrode is greater than that of the positive electrode, hence the cell capacity is limited by the positive electrode. The practical capacity of the Ni(OH) 2 positive electrode depends on the efficiency of the conductive network connecting the Ni(OH) 2 particles with the current collector. In this study, hot-pressed-type electrodes were prepared using fiber-like β-Ni(OH) 2 powder as the active material on a nickel mesh as a current collector. The effect of carbon black as a conductive network for Ni(OH) 2 active material and the partial substitution of Cu(OH) 2 for β-Ni(OH) 2 material on the electrode performance, are examined. The carbon black powder addition improves the utilization of the active material; however it lead to a decrease in stability of the electrode. The partial substitution of Cu(OH) 2 for β-Ni(OH) 2 significantly improves the coulombic efficiency of the β-Ni(OH) 2 active material and it also increases the specific discharge capacity and enhance the stability of the electrode. These findings showed that the copper modified β-Ni(OH) 2 electrodes possessed an improved specific capacity and stability and thus may be recognized as a promising hybrid material for battery electrode applications. • The β-phase Ni(OH) 2 is formed when hydrothermal treatment is applied. • Carbon black improves specific discharge capacity but not stability. • Cu 2+ substitution improves both capacity and stability.

Improving zinc porous electrode for secondary alkaline batteries: Toward a simple design of optimized 3D conductive network current collector

The internal migration of zinc within the thickness of porous composite negative electrodes for rechargeable zinc batteries causes detrimental shape change of the zinc electrode. It depends on various parameters linked to the electron conduction in the electrode: electronic percolation, conductive additives, primary current collector. This study highlights a simple solution, that drastically enhances the electrochemical performance of thick and porous zinc electrodes, by rethinking their architecture. Using a multiplicity of thin current collectors enables to create a 3D network of electronic percolation and a better repartition of the current lines within the electrode; as a result, the formation of multiple active zinc cores in the electrode volume is better controlled. This strategy allows to improve the management of zinc migration within the electrode structure, leading to minimal densification of each zinc core, and overall enables higher reversibility of zinc oxidation/reduction upon discharge/charge. It finally mitigates the initial drastic capacity fading observed on standard type calcium zincate negative electrode.

Effect of ZnO-Saturated Electrolyte on Rechargeable Alkaline Zinc Batteries at Increased Depth-of-Discharge

Rechargeable alkaline batteries containing zinc anodes suffer from redistribution of active material due to the high solubility of ZnO in the electrolyte, limiting achievable capacity and lifetime. Here, we investigate pre-saturating the KOH electrolyte with ZnO as a strategy to mitigate this issue, utilizing rechargeable Ni–Zn cells. In contrast to previous reports featuring this approach, we use more practical limited-electrolyte cells and systematically study ZnO saturation at different levels of zinc depth-of-discharge (DODZn), where the pre-dissolved ZnO is included in the total system capacity. Starting with 32 wt. % KOH, cells tested at 14%, 21%, and 35% DODZn with ZnO-saturated electrolyte exhibit 191%, 235%, and 110% longer cycle life respectively over identically tested cells with ZnO-free electrolyte, with similar energy efficiency and no voltage-related energy losses. Furthermore, anodes cycled in ZnO-saturated electrolyte develop more favorable compact zinc deposits with less overall mass loss. The effect of initial KOH concentration was also studied, with ZnO saturation enhancing cycle life for 32 wt % and 45 wt % KOH but not for 25 wt % KOH, likely due to cell failure by passivation rather than shorting. The simplicity of ZnO addition and its beneficial effect at high zinc utilization make it a promising means to make secondary alkaline zinc batteries more commercially viable.