ZnO Additive Boosts Charging Speed and Cycling Stability of Electrolytic Zn–Mn Batteries

Electrolytic aqueous zinc-manganese(Zn–Mn) batteries have the advantage of high discharge voltage and high capacity due to two-electron reactions. However, the pitfall of electrolytic Zn–Mn batteries is the sluggish deposition reaction kinetics of manganese oxide during the charge process and short cycle life. We show that, incorporating ZnO electrolyte additive can form a neutral and highly viscous gel-like electrolyte and render a new form of electrolytic Zn–Mn batteries with significantly improved charging capabilities. Specifically, the ZnO gel-like electrolyte activates the zinc sulfate hydroxide hydrate assisted Mn^(2+) deposition reaction and induces phase and structure change of the deposited manganese oxide(Zn_(2)Mn_(3)O_8·H_(2)O nanorods array), resulting in a significant enhancement of the charge capability and discharge efficiency. The charge capacity increases to 2.5 mAh cm^(-2) after 1 h constant-voltage charging at 2.0 V vs. Zn/Zn^(2+), and the capacity can retain for up to 2000 cycles with negligible attenuation. This research lays the foundation for the advancement of electrolytic Zn–Mn batteries with enhanced charging capability.

100 W-class green hydrogen production from ammonia at a dual-layer electrode containing a Pt-Ir catalyst for an alkaline electrolytic process

Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and is regarded as a future technology for production of CO_(2)-free pure hydrogen.Herein,a heterostructural Pt-Ir dual-layer electrode is developed and shown to achieve successful long-term operation in an ammonia electrolyzer with an anion exchange membrane(AEM).This electrolyzer consisted of eight membra ne electrode assemblies(MEAs)with a total geometric area of 200 cm~2 on the anode side,which resulted in a hydrogen production rate of 25 L h~(-1).We observed the degradation in MEA performance attributed to changes in the anode catalyst layer during hydrogen production via ammonia electrolysis.Furthermore,we demonstrated the relationship between the ammonia oxidation reaction(AOR)and the oxygen evolution reaction(OER).

Enhancing corrosion resistance of plasma electrolytic oxidation coatings on AM50 Mg alloy by inhibitor containing Ba(NO_(3))_(2) solutions

To enhance the long-term corrosion resistance of the plasma electrolytic oxidation(PEO)coating on the magnesium(Mg)alloy,an inorganic salt combined with corrosion inhibitors was used for posttreatment of the coating.In this study,the corrosion performance of PEO-coated AM50 Mg was significantly improved by loading sodium lauryl sulfonate(SDS)and sodium dodecyl benzene sulf-onate into Ba(NO_(3))_(2) post-sealing solutions.Scanning electron microscopy,X-ray photoelectron spectroscopy,X-ray diffraction,Fourier transform infrared spectrometer,and ultraviolet-visible analyses showed that the inhibitors enhanced the incorporation of BaO_(2) into PEO coatings.Electrochemical impedance showed that post-sealing in Ba(NO_(3))_(2)/SDS treatment enhanced corrosion resistance by three orders of magnitude.The total impedance value remained at 926Ω·cm^(2)after immersing in a 0.5wt%NaCl solution for 768 h.A salt spray test for 40 days did not show any obvious region of corrosion,proving excellent post-sealing by Ba(NO_(3))_(2)/SDS treatment.The corrosion resistance of the coating was enhanced through the synergistic effect of BaO2 pore sealing and SDS adsorption.

Enhanced recovery of high-purity Fe powder from iron-rich electrolytic manganese residue by slurry electrolysis

Iron-rich electrolytic manganese residue(IREMR)is an industrial waste produced during the processing of electrolytic metal manganese,and it contains certain amounts of Fe and Mn resources and other heavy metals.In this study,the slurry electrolysis technique was used to recover high-purity Fe powder from IREMR.The effects of IREMR and H2SO4 mass ratio,current density,reaction temper-ature,and electrolytic time on the leaching and current efficiencies of Fe were studied.According to the results,high-purity Fe powder can be recovered from the cathode plate,and the slurry electrolyte can be recycled.The leaching efficiency,current efficiency,and purity of Fe reached 92.58%,80.65%,and 98.72wt%,respectively,at a 1:2.5 mass ratio of H2SO4 and IREMR,reaction temperature of 60℃,electric current density of 30 mA/cm^(2),and reaction time of 8 h.In addition,vibrating sample magnetometer(VSM)analysis showed that the coercivity of electrolytic iron powder was 54.5 A/m,which reached the advanced magnetic grade of electrical pure-iron powder(DT4A coercivity standard).The slurry electrolytic method provides fundamental support for the industrial application of Fe resource recovery in IRMER.

Feasibility of Scaling up the Cost-Competitive and Clean Electrolytic Hydrogen Supply in China

Scaling up clean hydrogen supply in the near future is critical to achieving China’s hydrogen development target.This study established an electrolytic hydrogen development mechanism considering the generation mix and operation optimization of power systems with access to hydrogen.Based on the incremental cost principle,we quantified the provincial and national clean hydrogen production cost performance levels in 2030.The results indicated that this mechanism could effectively reduce the production cost of clean hydrogen in most provinces,with a national average value of less than 2 USD·kg^(-1) at the 40-megaton hydrogen supply scale.Provincial cooperation via power transmission lines could further reduce the production cost to 1.72 USD·kg^(-1).However,performance is affected by the potential distribution of hydrogen demand.From the supply side,competitiveness of the mechanism is limited to clean hydrogen production,while from the demand side,it could help electrolytic hydrogen fulfil a more significant role.This study could provide a solution for the ambitious development of renewables and the hydrogen economy in China.

Self-repairing Al_(2)O_(3)-TiO_(2)coatings fabricated through plasma electrolytic oxidation with various cathodic pulse parameters

The influence of cathodic pulse parameters was evaluated on plasma electrolytic oxidation(PEO)coatings grown on 7075 aluminum alloy in a silicate-based electrolyte containing potassium titanyl oxalate(PTO)using pulsed bipolar waveforms with various cathodic duty cycles and cathodic current densities.The coatings were characterized by SEM,EDS,and XRD.EIS was applied to investigate the electrochemical properties.It was observed that the increase of cathodic duty cycle and cathodic current density from 20%and 6 A/dm^(2) to 40%and 12 A/dm^(2) enhances the growth rate of the inner layer from 0.22 to 0.75μm/min.Adding PTO into the bath showed a fortifying effect on influence of the cathodic pulse and the mentioned change of cathodic pulse parameters,resulting in an increase of the inner layer growth rate from 0.25 to 1.10μm/min.Based on EDS analysis,Si and Ti were incorporated dominantly in the upper parts of the coatings.XRD technique merely detectedγ-Al_(2)O_(3),and there were no detectable peaks related to Ti and Si compounds.However,the EIS results confirmed that the incorporation of Ti^(4+)into alumina changed the electronic properties of the coating.The coatings obtained from the bath containing PTO using the bipolar waveforms with a cathodic duty cycle of 40%and current density values higher than 6 A/dm^(2) showed highly appropriate electrochemical behavior during 240 d of immersion due to an efficient repairing mechanism.Regarding the effects of studied parameters on the coating properties,the roles of cathodic pulse parameters and PTO in the PEO process were highlighted.

Fundamental Understanding on Selenium Electrochemistry:From Electrolytic Cell to Advanced Energy Storage

Selenium(Se),as an important quasi-metal element,has attracted much attention in the fields of thin-film solar cells,electrocatalysts and energy storage applications,due to its unique physical and chemical properties.However,the electrochemical behavior of Se in different systems from electrolytic cell to battery are complex and not fully understood.In this article,we focus on the electrochemical processes of Se in aqueous solutions,molten salts and ionic liquid electrolytes,as well as the application of Se-containing materials in energy storage.Initially,the electrochemical behaviors of Se-containing species in different systems are comprehensively summarized to understand the complexity of the kinetic processes and guide the Se electrodeposition.Then,the relationship between the deposition conditions and resulting structure and morphology of electrodeposited Se is discussed,so as to regulate the morphology and composition of the products.Finally,the advanced energy storage applications of Se in thin-film solar cells and secondary batteries are reviewed,and the electrochemical reaction processes of Se are systematically comprehended in monovalent and multivalent metal-ion batteries.Based on understanding the fundamental electrochemistry mechanism,the future development directions of Se-containing materials are considered in view of the in-depth review of reaction kinetics and energy storage applications.

Hydroelectrolytic and Energetic Replenisher in Horses Undergoing Marcha Training

The study aimed to assess the clinical, laboratory, and blood gas analysis of horses undergoing Marcha training and the effects of voluntary ingestion of hydroelectrolytic and energy replenishers after exercise. Eight horses of both genders aged between 5 and 10 years, were included in the study. The exercise consisted of a 10-min warm-up followed by 45 min uninterrupted Marcha on a flat dirt track in the morning. After exercise, the horses received one of the following treatments: Drinking water (control group);Hydroelectrolytic and energy replenisher containing sodium chloride, potassium chloride, calcium acetate, magnesium chloride, sodium citrate, dextrose, maltodextrin, and sucrose in three different concentrations (Replenishers A, B, and C). The horses were distributed across the four treatments in a 4 × 4 Latin Squares design using a Split-plot system with 48-hr intervals. Clinical and laboratory evaluations were conducted at four time points: T0 - 5 min before exercise;T1 - up to 5 min after exercise;T2 - 2 hr after starting treatment;and T4 - 4 hr after beginning treatment. Concentrations of urea, creatinine, lactate, phosphorus, and ionized calcium significantly changed after exercise. An increase in blood pH and a decrease in chloride concentrations were observed when replenishers B and C were offered after exercise. The replacements were ingested spontaneously by the animals in a volume greater than that of the control group (water). Replacement B was the most ingested by the animals, demonstrating its greatest potential.

Pulsed electrolysis of carbon dioxide by large-scale solid oxide electrolytic cells for intermittent renewable energy storage

CO_(2) electrolysis with solid oxide electrolytic cells(SOECs)using intermittently available renewable energy has potential applications for carbon neutrality and energy storage.In this study,a pulsed current strategy is used to replicate intermittent energy availability,and the stability and conversion rate of the cyclic operation by a large-scale flat-tube SOEC are studied.One hundred cycles under pulsed current ranging from -100 to -300 mA/cm^(2) with a total operating time of about 800 h were carried out.The results show that after 100 cycles,the cell voltage attenuates by 0.041%/cycle in the high current stage of−300 mA/cm^(2),indicating that the lifetime of the cell can reach up to about 500 cycles.The total CO_(2) conversion rate reached 52%,which is close to the theoretical value of 54.3% at -300 mA/cm^(2),and the calculated efficiency approached 98.2%,assuming heat recycling.This study illustrates the significant advantages of SOEC in efficient electrochemical energy conversion,carbon emission mitigation,and seasonal energy storage.

A super wear-resistant coating for Mg alloys achieved by plasma electrolytic oxidation and discontinuous deposition

Magnesium alloys are lightweight materials with great potential,and plasma electrolytic oxidation(PEO)is effective surface treatment for necessary improvement of corrosion resistance of magnesium alloys.However,the∼14µm thick and rough PEO protection layer has inferior wear resistance,which limits magnesium alloys as sliding or reciprocating parts,where magnesium alloys have special advantages by their inherent damping and denoising properties and attractive light-weighting.Here a novel super wear-resistant coating for magnesium alloys was achieved,via the discontinuous sealing(DCS)of a 1.3µm thick polytetrafluoroethylene(PTFE)polymer layer with an initial area fraction(A_(f))of 70%on the necessary PEO protection layer by selective spraying,and the wear resistance was exceptionally enhanced by∼5500 times in comparison with the base PEO coating.The initial surface roughness(Sa)under PEO+DCS(1.54µm)was imperfectly 59%higher than that under PEO and conventional continuous sealing(CS).Interestingly,DCS was surprisingly 20 times superior for enhancing wear resistance in contrast to CS.DCS induced nano-cracks that splitted DCS layer into multilayer nano-blocks,and DCS also provided extra space for the movement of nano-blocks,which resulted in rolling friction and nano lubrication.Further,DCS promoted mixed wear of the PTFE polymer layer and the PEO coating,and the PTFE layer(HV:6 Kg·mm^(−2),A_(f):92.2%)and the PEO coating(HV:310 Kg·mm^(−2),A_(f):7.8%)served as the soft matrix and the hard point,respectively.Moreover,the dynamic decrease of Sa by 29%during wear also contributed to the super wear resistance.The strategy of depositing a low-frictional discontinuous layer on a rough and hard layer or matrix also opens a window for achieving super wear-resistant coatings in other materials.

The mechanism for tuning the corrosion resistance and pore density of plasma electrolytic oxidation(PEO)coatings on Mg alloy with fluoride addition

Here we prepared PEO coatings on Mg alloys in silicate-NaOH-phosphate electrolyte containing different concentrations of NaF addition.The detailed microstructural characterizations combining with potentiodynamic polarization and electrochemical impedance spectra(EIS)were employed to investigate the roles of fluoride in the growth and corrosion properties of PEO coating on Mg.The result shows the introduction of NaF led to a fluoride-containing nanolayer(FNL)formed at the Mg/coating interface.The FNL consists of MgO nanoparticles and insoluble MgF_(2)nanoparticles(containing rutile phase and cubic phase).The increase in the NaF concentration of the electrolyte increases the thickness and the MgF_(2)content in the FNL.When anodized in the electrolyte containing 2 g/L NaF,the formed FNL has the highest thickness of 100-200 nm along with the highest value of x of∼0.6 in(MgO)_(1-x)(MgF_(2))x resulted in the highest corrosion performance of PEO coating.In addition,when anodized in the electrolyte containing a low NaF concentration(0.4-0.8 g/L),the formed FNL was thin and discontinuous,which would decrease the pore density and increase the coating's uniformness simultaneously.

Preparation and property of self-sealed plasma electrolytic oxide coating on magnesium alloy

Plasma electrochemical oxidation (PEO) is a surface modification technology to form ceramic coatings on magnesium alloys However,its application is limited due to its defects.This work reports a novel preparation of in-situ sealing of PEO coatings by four-layer voltage and sol addition.The morphology and structure were characterized by scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS),and X-ray diffractometer (XRD).Image-Pro Plus 6.0 was used to determine the porosity of the coating,which was decreased from 8.53%to 0.51%.Simultaneously,the coating thickness was increased by a factor of four.The anti-corrosion performance of each sample was evaluated using electrochemical tests,and the findings revealed that the corrosion current density of coatings (i_(corr)) of the samples were lowered from 9.152×10^(-2) to 6.152×10^(-4) mA·cm^(-2),and the total resistance (R_(T)) of the samples were enhanced from 2.19×10^(4) to 2.33×10^(5)Ω·cm^(2).The salt spray test used to simulate the actual environment showed that corrosion points appeared on the surface of the coating only at the 336 h.In addition,the mechanism of PEO self-sealing behavior was described in this article.

Synthesis of zeolite A and zeolite X from electrolytic manganese residue,its characterization and performance for the removal of Cd^(2+)from wastewater

Electrolytic manganese residue(EMR)can cause serious environmental and biological hazards.In order to solve the problem,zeolite A(EMRZA)and zeolite X(EMRZX)were synthesized by EMR.The pure phase zeolites were synthesized by alkaline melting and hydrothermal two-step process,which had high crystallinity and excellent crystal control.And the optimum conditions for synthesis of zeolite were investigated:NaOH-EMR mass ratio=1.2,L/S=10,hydrothermal temperature=90℃,and hydrothermal time=6 h.Then,EMRZA and EMRZX showed excellent adsorption of Cd^(2+).When T=25℃,time=120min,pH=6,C0=518 mg·L^(-1),and quantity of absorbent=1.5 g·L^(-1),the adsorption capacities of EMRZA and EMRZX reached 314.2 and 289,5 mg·g^(-1),respectively,In addition,after three repeated adsorption-desorption cycles,EMRZA and EMRZX retained 80%and 74%of the initial zeolites removal rates,respectively.Moreover,adsorption results followed quasi-second-order kinetics and monolayer adsorption,which was regulated by a combination of chemisorption and intra-particle diffusion mechanisms.The adsorption mechanism was ions exchange between Cd^(2+)and Na+.In summary,it has been confirmed that EMRZA and EMRZX can be reused as highly efficient adsorbents to treat Cd^(2+)-contaminated wastewater.

Incorporation of LDH nanocontainers into plasma electrolytic oxidation coatings on Mg alloy

In-situ incorporation of layered double hydroxides(LDH)nanocontainers into plasma electrolytic oxidation(PEO)coatings on AZ91 Mg alloy has been achieved in the present study.Fumarate was selected as Mg corrosion inhibitor for exchange and intercalation into the nanocontainers,which were subsequently incorporated into the coating.It was found that the thickness and compactness of the coatings were increased in the presence of LDH nanocontainers.The corrosion protection performance of the blank PEO,LDH containing PEO and inhibitor loaded coatings was evaluated by means of polarization test and electrochemical impedance spectroscopy(EIS).The degradation process and corrosion resistance of PEO coating were found to be greatly affected by the loaded inhibitor and nanocontainers by means of ion-exchange when corrosion occurs,leading to enhanced and stable corrosion resistance of the substrate.

A self-healing and bioactive coating based on duplex plasma electrolytic oxidation/polydopamine on AZ91 alloy for bone implants

Magnesium(Mg) alloys are well-known in biomedical materials owing to their elastic module near to bone, biocompatibility and biodegradation properties. Nevertheless, poor corrosion resistance hinders their biomedical applications. Besides, it is necessary to endow Mg alloys with bioactive property, which is crucial for temporary bone implants. Here, a self-healing, corrosion resistant and bioactive duplex coating of plasma electrolytic oxidization(PEO)/polydopamine(PDA) is applied on AZ91 substrate using PEO and subsequent electrodeposition process. Moreover, the role of different electrodeposition times(60 s, 120 s) and dopamine concentrations(1 and 1.5 mg/ml) to improve corrosion resistance, bioactivity, biocompatibility and self-healing property and its mechanism are investigated. The results indicate that the PEO coating is efficiently sealed by the PDA, depending on the electrodeposition parameters. Noticeably, electrodeposition for 120 s in dopamine concentration of 1 mg/ml(120T-1C) results in the formation of uniform and crack-free PDA coating. Duplex PEO/PDA coatings reveal high bioactivity compared to PEO coating, owing to electrostatic interaction between PDA top-layer and calcium and phosphate ions as well as high hydrophilicity of coatings. In addition, duplex PEO/PDA coatings also show improved and more stable protective performance than the PEO and bare alloy, depending on the PDA deposition parameters. Noticeably, the corrosion current density of the 120T-1C decreases one orders of magnitude compared to PEO. In addition, the presence of a broad passivation region in the anodic polarization branch shows durable self-healing property via Zipper-like mechanism, demonstrating the duplex coating could preserve promising corrosion resistance.Furthermore, the cytocompatibility of duplex coated samples is also confirmed via interaction with MG63 cells. In summary, the PEO/PDA coating with great corrosion protection, self-healing ability, bioactivity and biocompatibility could be a promising candidate for degradable magnesium-based implants.

Corrosion behavior of composite coatings containing hydroxyapatite particles on Mg alloys by plasma electrolytic oxidation: A review

Mg and its alloys have been introduced as promising biodegradable materials for biomedical implant applications due to their excellent biocompatibility, mechanical behavior, and biodegradability. However, their susceptibility to rapid corrosion within the body poses a significant challenge and restricts their applications. To overcome this issue, various surface modification techniques have been developed to enhance the corrosion resistance and bioactivity of Mg-based implants. PEO is a potent technique for producing an oxide film on a surface that significantly minimizes the tendency to corrode. However, the inevitable defects due to discharges and poor biological activity during the coating process remain a concern. Therefore, adding suitable particles during the coating process is a suitable solution. Hydroxyapatite(HAp)has attracted much attention in the development of biomedical applications in the scientific community. HAp shows excellent biocompatibility due to its similarity in chemical composition to the mineral portion of bone. Therefore, its combination with Mg-based implants through PEO has shown significant improvements in their corrosion resistance and bioactivity. This review paper provides a comprehensive overview of the recent advances in the preparation, characterization, corrosion behavior and bioactivity applications of HAp particles on Mg-based implants by PEO.

Electrochemical response of MgO/Co_(3)O_(4) oxide layers produced by plasma electrolytic oxidation and post treatment using cobalt nitrate

This work looked into the influence of the sealing treatment on the structural feature and electrochemical response of AZ31 Mg alloy coated via plasma electrolytic oxidation(PEO).Here,the inorganic layers produced by PEO in an alkaline-phosphate electrolyte were subsequently immersed for different periods in cold(60°C)and hot(100°C)aqueous solutions containing either 1 or 3 gr of cobalt nitrate hexahydrate in the presence of hydrogen peroxide as an initiator.The results showed that the sealing treatments in the hot solutions could trigger the hydration reactions of PEO coating which would largely assist the surface incorporation of Co_(3)O_(4)into the coating.In contrast,the sealing in cold solutions led to less compact coatings,which was attributed to the fact the hydration reactions would be restricted at 60°C.A nearly fully sealed coating with a porosity of~0.5%was successfully formed on the sample immersed in the hot solution containing 1 gr of cobalt nitrate hexahydrate.Thus,the electrochemical stability of this fully sealed coating was superior to the other samples as it had the lowest corrosion current density(4.71×10^(-10)A·cm^(-2))and the highest outer layer resistance(3.81×10^(7)Ω·cm^(2)).The composite coatings developed in this study are ideal for applications requiring high electrochemical stability.

Study on Influencing Factors of Methane Production Efficiency of Microbial Electrolytic Cell with CO_(2) as Carbon Source

Reducing CO_(2) to produce methane through microbial electrolytic cell(MEC)is one of the important methods of CO_(2) resource utilization.In view of the problem of low methanogenesis rate and weak CO_(2) conversion rate in the reduction process,theflowfield environment of the cathode chamber is changed by changing the upper gas cir-culation rate and the lower liquid circulation rate of the cathode chamber to explore the impact on the reactor startup and operation and products.The results showed that under certain conditions,the CO_(2) consumption and methane production rate could be increased by changing the upper gas recirculation rate alone,but the increase effect was not obvious,but the by-product hydrogen production decreased significantly.Changing the lower liquid circulation rate alone can effectively promote the growth of biofilm,and change the properties of biofilm at the later stage of the experiment,with the peak current density increased by 16%;The methanogenic rate decreased from the peak value of 0.561 to 0.3 mmol/d,and the CO_(2) consumption did not change signifi-cantly,which indicated that CO_(2) was converted into other organic substances instead of methane.The data after coupling the upper gas circulation rate with the lower liquid circulation rate is similar to that of only changing the lower liquid circulation rate,but changing the upper gas circulation rate can alleviate the decline of methane pro-duction rate caused by the change of biofilm properties,which not only improves the current density,but also increases the methane production rate by 0.05 mmol/d in the stable period.This study can provide theoretical and technical support for the industrial application scenario offlowfield regulation intervention of microbial elec-trolytic cell methanogenesis.

Formation process of composite plasma electrolytic oxidation coating containing zirconium oxides on AM50 magnesium alloy

The formation processes of a composite ceramic coating on AM50 magnesium alloy prepared by plasma electrolytic oxidation （PEO） in a K 2 ZrF 6 electrolyte solution were studied by scanning electron microscope （SEM） and energy dispersive X-ray spectroscope （EDX）. Electrochemical impedance spectroscopy （EIS） tests were used to study the variation of the corrosion resistance of the coating during the PEO treatment. The results show that the coating formed on Mg alloy is mainly composed of MgO and MgF 2 when the applied voltage is lower than the sparking voltage, and zirconium oxides start to be deposited on Mg substrate after the potential exceeding the sparking voltage. The corrosion resistance of the coating increases with increasing the applied voltage.

Effects of current density on microstructure and properties of plasma electrolytic oxidation ceramic coatings formed on 6063 aluminum alloy

Plasma electrolytic oxidation (PEO) ceramic coatings were fabricated in a silicate-based electrolyte with the addition of potassium fluorozirconate (K2ZrF6) on 6063 aluminum alloy, and the effects of current density on microstructure and properties of the PEO coatings were studied. It was found that pore density of the coatings decreased with increasing the current density. The tribological and hardness tests suggested that the ceramic coating produced under the current density of 15 A/dm2showed the best mechanical property, which matched well with the phase analysis. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves proved that the coating obtained under 15 A/dm2 displayed the best anti-corrosion property, which was directly connected with morphologies of coatings.