Average Cell Voltage Research Articles

Co-production of hydrogen, oxygen, and electricity via an integrated solar-driven system with decoupled water electrolyzer and Na-Zn ion battery

Combining water electrolysis and rechargeable battery technologies into a single system holds great promise for the co-production of hydrogen (H2) and electricity. However, the design and development of such systems is still in its infancy. Herein, an integrated hydrogen-oxygen (O2)-electricity co-production system featuring a bipolar membrane-assisted decoupled electrolyzer and a Na-Zn ion battery was established with sodium nickelhexacyanoferrate (NaNiHCF) and Zn2+/Zn as dual redox electrodes. The decoupled electrolyzer enables to produce H2 and O2 in different time and space with almost 100% Faradic efficiency at 100 mA cm−2. Then, the charged NaNiHCF and Zn electrodes after the electrolysis processes formed a Na-Zn ion battery, which can generate electricity with an average cell voltage of 1.75 V at 10 mA cm−2. By connecting Si photovoltaics with the modular electrochemical device, a well-matched solar driven system was built to convert the intermittent solar energy into hydrogen and electric energy with a solar to hydrogen-electricity efficiency of 16.7%, demonstrating the flexible storage and conversion of renewables.

Electrorefining of Crude Solder for the Production of Fine Solder in Methanesulfonic Acid Medium: Electrolyte Conductivity and Electrorefining Process.

At present, the refining of crude solder has many drawbacks such as high energy consumption, high environmental pollution, equipment corrosion, and low current efficiency. Therefore, a new technique for refining crude solder is of great practical importance. In this work, the electrorefining of crude solder in methanesulfonic acid (MSA) medium was studied. The conductivities of tin-MSA solutions had been measured and modeled to characterize the electrolyte. The effects of the electrorefining conditions on the electrorefining process were investigated systematically. The cell voltage, current efficiency, and fine solder appearance were used to characterize the electrorefining performance. Some operating parameters of the electrorefining process are established as follows: current density 207 A/m2, tin concentration 120-160 g/L, free-MSA concentration 90-120 g/L, electrode spacing 4 cm, and temperature 305.15-315.15 K. Under these conditions, the average cell voltage is 0.30 V and the current efficiency is 99.31%. The total content of tin and lead of the fine solder with good product appearance is >99.99%. This technique offers low energy consumption, high productivity, and low environmental pollution.

Optimization Potential for Operating PEMFC Systems Under High-Altitude Conditions

The PEMFC technology is on the rise to be implemented as climate neutral power source in next generation aircraft. Despite the PEMFC’s high efficiency at ground level, it suffers from severe power losses when it is operated under high-altitude conditions, i.e. low ambient pressure and temperature.In this study, a fuel cell system consisting of a 120 cells PEMFC stack, an air blower, an anode recirculation pump and a cooling unit is investigated experimentally inside an altitude test chamber, where the ambient pressure and temperature can be controlled. In an extensive parameter study, the fuel cell’s cathode stoichiometry and the stack temperature are varied while the system is operated at different average cell voltage levels under high-altitude conditions. The ambient pressure is varied between 1000 and 500 hPa, the latter corresponding to an altitude of 5600 m. The air blower inflow temperature is varied between 40 and -30 °C. By means of statistical design of experiment methods an empirical model is derived from the measurements, which represents the system performance depending on the five-dimensional parameter space, i.e. cathode stoichiometry, stack temperature, average cell voltage, ambient pressure and blower inflow temperature.The model is evaluated in order to identify the optimal parameter configurations for stoichiometry and stack temperature control, yielding the maximum system net power at high-altitude operation. The results show that the negative effects in terms of power losses due to low ambient pressure prevail over low air temperature. However, the low temperature is non-negligible in terms of the air density, affecting the required blower power to maintain a certain stoichiometry and consequently also affecting the system net power. When operating at high-altitude conditions with optimized control parameters, the resulting net power output is significantly higher compared to the net power output obtained with the default control parameters suggested by the manufacturer. The main reason for this power increase can be found in the optimized membrane humidification. Under high-altitude conditions, humidification becomes more sensitive to deviations from the identified optimal control parameters. The results highlight the large optimization potential through altitude-adaptive control of fuel cell systems for aviation applications.

Durable Anode Electrodes with Facile and Scalable Electrodeposition for Green Hydrogen Production at Industrial Scale

Highly efficient electrodes with facile fabrication, excellent performance, low cost, and high durability are of paramount significance for the development of gigawatt-scale proton exchange membrane electrolyzer cells (PEMECs).1-5 In this study, amorphous Ir0.8Ru0.2Ox (80% Ir, 20% Ru) catalysts with high intrinsic activity are first deposited on Ti sintered powder via a room temperature electrodeposition process, serving as high-performance anode electrodes in PEMECs. Different Ir loadings of 0.16, 0.24, 0.4, and 0.72 mg/cm2 were deposited and evaluated in PEMECs. As a result, low average cell voltages of 1.623 and 1.875 V are achieved at 2 and 6 A/cm2, respectively, achieving high cell efficiency of 91%-94% at 2 A/cm2, superior to the commercial CCM.1, 3, 6 Moreover, with an Ir loading of 0.4 mg/cm2, the Ir0.8Ru0.2Ox electrode shows a low-performance loss after a 900-h operation at an ultrahigh current density of 5 A/cm2, resulting in a low degradation rate of only about 39 uV/h in the last 200 h. The remarkable performance and durability of the Ir0.8Ru0.2Ox electrode are mainly due to the high intrinsic activity of Ir0.8Ru0.2Ox catalysts exposing abundant active sites, sufficient Ir3+ content, a well-controlled Ir and Ru ratio, efficient phase transformation, and excellent catalyst support. References Mo, Jingke, Zhenye Kang, Scott T. Retterer, David A. Cullen, Todd J. Toops, Johney B. Green Jr, Matthew M. Mench, and Feng-Yuan Zhang. "Discovery of True Electrochemical Reactions for Ultrahigh Catalyst Mass Activity in Water Splitting." Science Advances 2, no. 11 (2016): e1600690.Ding, Lei, Weitian Wang, Zhiqiang Xie, Douglas S. Aaron, Adam Paxson, Monjid Hamdan, Matthew M. Mench, and Feng-Yuan Zhang. "Efficient Integrated Electrode Enables High-Current Operation and Excellent Stability for Green Hydrogen Production." ACS Sustainable Chemistry & Engineering 11, no. 30 (2023): 11219-11228.Ding, Lei, Zhiqiang Xie, Shule Yu, Weitian Wang, Alexander Y. Terekhov, Brian K. Canfield, Christopher B. Capuano, Alex Keane, Kathy Ayers, David A. Cullen, Feng-Yuan Zhang. "Electrochemically Grown Ultrathin Platinum Nanosheet Electrodes with Ultralow Loadings for Energy-Saving and Industrial-Level Hydrogen Evolution" Nano-Micro Letters 15, 144 (2023).Ding, Lei, Weitian Wang, Zhiqiang Xie, Kui Li, Shule Yu, Christopher B. Capuano, Alex Keane, Kathy Ayers, and Feng-Yuan Zhang. "Highly Porous Iridium Thin Electrodes with Low Loading and Improved Reaction Kinetics for Hydrogen Generation in PEM Electrolyzer Cells." ACS Applied Materials & Interfaces (2023): 24284.Xie, Zhiqiang, Shule Yu, Xiaohan Ma, Kui Li, Lei Ding, Weitian Wang, David A. Cullen et al. "MoS2 Nanosheet Integrated Electrodes with Engineered 1T-2H Phases and Defects for Efficient Hydrogen Production in Practical PEM Electrolysis." Applied Catalysis B: Environmental 313 (2022): 121458.Xie, Zhiqiang, Lei Ding, Shule Yu, Weitian Wang, Christopher B. Capuano, Alex Keane, Kathy Ayers, David A. Cullen, Harry M. Meyer III, and Feng-Yuan Zhang. "Ionomer-free nanoporous iridium nanosheet electrodes with boosted performance and catalyst utilization for high-efficiency water electrolyzers." Applied Catalysis B: Environmental 341 (2024): 123298. Figure 1

Machine learning modeling for fuel cell-battery hybrid power system dynamics in a Toyota Mirai 2 vehicle under various drive cycles

Electrification is considered essential for the decarbonization of mobility sector, and understanding and modeling the complex behavior of modern fuel cell-battery electric-electric hybrid power systems is challenging, especially for product development and diagnostics requiring quick turnaround and fast computation. In this study, a novel modeling approach is developed, utilizing supervised machine learning algorithms, to replicate the dynamic characteristics of the fuel cell-battery hybrid power system in a 2021 Toyota Mirai 2nd generation (Mirai 2) vehicle under various drive cycles. The entire data for this study is collected by instrumenting the Mirai vehicle with in-house data acquisition devices and tapping into the Mirai controller area network bus during chassis dynamometer tests. A multi-input - multi-output, feed-forward artificial neural network architecture is designed to predict not only the fuel cell attributes, such as average minimum cell voltage, coolant and cathode air outlet temperatures, but also the battery hybrid system attributes, including lithium-ion battery pack voltage and temperature with the help of 15 system operating parameters. Over 21,0000 data points on various drive cycles having combinations of transient and near steady-state driving conditions are collected, out of which around 15,000 points are used for training the network and 6,000 for the evaluation of the model performance. Various data filtration techniques and neural network calibration processes are explored to condition the data and understand the impact on model performance. The calibrated neural network accurately predicts the hybrid power system dynamics with an R-squared value greater than 0.98, demonstrating the potential of machine learning algorithms for system development and diagnostics.

Exploring the Performance of Alkaline Water Electrolyzers Under Dynamic Operational Conditions

Green hydrogen, produced through water electrolysis driven by Renewable Energy Sources (RES), is a compelling solution for storing renewable energy. Directly coupling RES with water electrolyzers enhances system efficiency and cost-effectiveness. Alkaline water electrolysis, a mature and cost-effective technology, faces challenges operating under fluctuating RES conditions using AC/DC convertor , which supply rippled DC. A comprehensive understanding of electrolyzer performance in dynamic conditions is crucial for developing durable, efficient systems.In the present experimental study, we extensively explored the performance of alkaline water electrolyzers and the key factors influencing it under dynamic operational conditions. The electrolytic cell was constructed using a zero-gap configuration, comprising a NiCoOx-based anode deposited on a Ni-mesh and an Ln-doped RuOx cathode deposited on a fine mesh of Ni metal. The Zirfon Perl UTP500 membrane served as a separator between the two cell compartments [1]. A 7.0 Molar KOH electrolyte at a room temperature of approximately 30°C was employed. The cell underwent dynamic operational mode through the application of a square wave cell voltage, shown in Fig.1 (a), utilizing the NF BP4620 power supply. Square waves with different frequencies, specifically 1, 100, 1000, and 3000 Hz, were employed. Steady-state operations were conducted while applying various DC voltages, serving as a reference study. The resulting current and the actual cell voltage waveforms were monitored and recorded using a high-resolution oscilloscope (YOKOGAWA DL850E). The flow of H2 gas was measured using a film flow meter (HORIBA STEC, SF series VP-3). The apparent power, real power, and reactive power components were calculated using formulas from a previously published report [2]. Subsequently, the specific energy consumption was determined for each condition.The applied cell voltages were categorized into two groups. In the first category, the maximum cell voltage (Vmax) was set at 2.0 V, a value sufficiently high and suitable for industrial cell operation when applied in a DC mode. Within this category, the minimum cell voltage (Vmin) took various values, namely 1.8, 1.6, and 1.4 V. In the second category, the average cell voltage was maintained at a constant 2.0 V, while the amplitude of the waveform was adjusted to 0.2 and 0.4 V by modifying both Vmax and Vmin. Figure 1(b) depicts the resulting current of the voltage waveform at 100 Hz, illustrating three different Vmin values. The figure reveals that at a high Vmin of 1.8V, the current consistently maintained positive values during the voltage cycle, indicating that the double-layer capacitance remained charged throughout the operational period. However, with Vmin set at 1.6V, a relatively small capacitive current emerged, suggesting partial discharge of the double-layer capacitance. Moreover, at a lower Vmin of 1.4V, the cell voltage became insufficient to drive water electrolysis in the current cell. Consequently, a relatively large negative (capacitive) current manifested during the Vmin period, denoting a deep discharge of the double-layer capacitance.The obtained results revealed a profound influence of the charge and discharge status of the double-layer capacitance on the AWE cell's performance throughout the voltage cycles. Notably, when the double-layer capacitor remained fully charged during the voltage cycles, minimal impact of the frequency was observed on key performance parameters, including H2 flow rate that shown in figure 1 (c), specific energy consumption that shown in figure 1 (d), and power factor. However, under conditions of partial discharge within the cell voltage cycles, a noticeable correlation between the size and frequency of the voltage waveform and the AWE cell's performance emerged. Deep discharge of the double-layer capacitance led to a frequency-dependent reduction in H2 flow rate, attributed to incomplete charge/discharge cycles. Hence, the critical factor influencing the performance of the electrolytic cell during dynamic operation is the condition (charging/discharging) of the double-layer capacitance. These findings offer valuable insights into optimizing the dynamic operation of AWE cells for enhanced efficiency and performance. Acknowledgments: This research was partially supported by New Energy and Industrial Technology Development Organization (NEDO).

Large-Scale and Simple Synthesis of NiFe(OH)x Electrode Derived from Raney Ni Precursor for Efficient Alkaline Water Electrolyzer

Water electrolysis is a crucial technology in the production of hydrogen energy. Due to the escalating industrial demand for green hydrogen, the required electrode size for a traditional alkaline water electrolyzer has been increasing. Numerous studies have focused on developing highly active oxygen evolution reaction (OER) catalysts for water electrolysis. However, there remains a significant gap between the microscale synthesis of catalysts in laboratory settings and the macroscale preparation required for industrial scenarios. This challenge is particularly pronounced in the synthesis of sizable self-supported electrodes. In this work, we employed a commercially available Raney Ni-coated Ni mesh as a precursor material to fabricate a self-supported NiFe(OH)x@Raney Ni anode with a substantial dimension exceeding 300 mm through a straightforward immersion technique. The as-prepared electrode exhibited remarkable electrocatalytic OER activity, as an overpotential of only 240 mV is required to achieve 10 mA cm−2. This performance is comparable to that of NiFe-LDHs synthesized via a hydrothermal method, which is difficult to scale up for industrial applications. Furthermore, the electrode demonstrated exceptional durability, maintaining stable operation for over 100 h at a current density of 500 mA cm−2. The large-scale electrode displayed consistent overpotentials across various areas, indicating uniform catalytic activity. When integrated into an alkaline water electrolysis device, it delivered an average cell voltage of 1.80 V at 200 mA cm−2 and achieved a direct current hydrogen production energy consumption as low as 4.3 kWh/Nm3. These findings underline the suitability of electrodes for industrial scale applications, offering a promising alternative for energy-efficient hydrogen production.

Multi-Objective Optimization of Cell Voltage Based on a Comprehensive Index Evaluation Model in the Aluminum Electrolysis Process

In the abnormal situation of an aluminum electrolysis cell, the setting of cell voltage is mainly based on manual experience. To obtain a smaller cell voltage and optimize the operating parameters, a multi-objective optimization method for cell voltage based on a comprehensive index evaluation model is proposed. Firstly, a comprehensive judgment model of the cell state based on the energy balance, material balance, and stability of the aluminum electrolysis process is established. Secondly, a fuzzy neural network (FNN) based on the autoregressive moving average (ARMA) model is designed to establish the cell-state prediction model in order to finish the real-time monitoring of the process. Thirdly, the optimization goal of the process is summarized as having been met when the difference between the average cell voltage and the target value reaches the minimum, and the condition of the cell is excellent. And then, the optimization setting model of cell voltage is established under the constraints of the production and operation requirements. Finally, a multi-objective antlion optimization algorithm (MOALO) is used to solve the above model and find a group of optimized values of the electrolysis cell, which is used to realize the optimization control of the cell state. By using actual production data, the above method is validated to be effective. Moreover, optimized operating parameters are used to verify the prediction model of cell voltage, and the cell state is just excellent. The method is also applied to realize the optimization control of the process. It is of guiding significance for stabilizing the electrolytic aluminum production and achieving energy saving and consumption reduction.

Novel Additives in Copper Electrorefining-Small Laboratory Scale.

This research aimed to evaluate the effectiveness of new organic substances, including a novel ionic liquid based on polyhexamethylenebiguanidine, polyhexamethyleneguanidine, and safranin in the copper electrorefining process. Experiments were conducted on a small laboratory scale using industrial copper anodes. Single doses of new additives did not improve process indicators (current efficiency, average cell voltage, specific energy consumption) or the quality of copper cathode deposits. However, a combination of a new ionic liquid based on polyhexamethylenebiguanidine and thiourea resulted in a satisfactory current efficiency of 97%, an average cell voltage of 0.110 V, a low specific energy consumption index of approximately 100 kWh/tCu, and smooth cathode surfaces. These results were superior to those obtained with industrial additives (bone glue and thiourea). The findings enhance our understanding of how these substances influence the electrorefining process and suggest the potential for more efficient and sustainable methods. Further research is recommended to validate these findings and explore their industrial applications.

Feeding a Membrane-less Microbial Fuel Cell by Mixed Municipal and Industrial Wastewater

Due to the constant growth of the world's population, the amount of generated wastewater is also constantly increasing. One of the devices that can use wastewater as a raw material for energy production is a microbial fuel cell (MFC). MFCs technology is constantly evolving. However, to increase its use, it is necessary to improve its efficiency. There are various possibilities to ensure this, such as the use of new electrode materials, new cell designs, or the use of wastewaters from different sources. In this paper the analysis of MFC operation (cell voltage, power, and current density) fed by mixed municipal and industrial wastewaters was shown. Moreover, the change in time of COD was analyzed. Due to cost reduction the membrane-less microbial fuel cell (ML-MFC) was chosen. It was noted that the addition of concentrated process wastewater increases the COD reduction time in the ML-MFC. An increase of generated bioelectricity during fed ML-MFC by mixed municipal and industrial (process wastewater from yeast production) wastewater was demonstrated. The highest values of average cell voltage (598 mV), maximum power (4.47 mW) and maximum current density (0.26 mA·cm-2) were obtained for a 10% share of yeast process wastewater in the mixed wastewater, which fed the ML-MFC.

Breaking the Passivity Wall of Metals: Exempli Gratia Non-Aqueous Ti–Air Battery

In recent years, metal–air batteries have been gaining much attention as one crucial line of development as promising energy storage devices due to possessing high theoretical specific energies and energy densities while utilizing cost-effective, safe, and environmentally friendly electrode materials. Among various possible metal–air configurations, mostly Zn–, Fe–, and Al–air have been the research focus for many decades. Up to now, Ti has not been considered as an active anode material, although it is a light metal that can possibly transfer up to 4 electrons. The reason behind this is that the electrochemical behavior of Ti is known for its passivity in various media and, also, it is conceptually mistaken as an expensive metal.Herein, we report a novel non-aqueous primary Ti–air battery utilizing 1-ethyl-3-methylimidazolium oligofluorohydrogenate (EMIm(HF)2.3F) room temperature ionic liquid as electrolyte. Initially, the electrochemical behavior of Ti was studied by potentiodynamic polarization, which revealed the first insights into its electrochemical activity. Subsequently, the galvanostatic discharge experiments were conducted to evaluate the performance of Ti–air batteries in full-cells. The battery could successfully be operated under moderate current densities (up to 0.75 mA/cm2) with an average cell voltage of 1–1.2 V, yielding up to a discharge capacity of 66 mAh/cm2. Post-mortem characterization of the electrode surfaces was performed by SEM in combination with EDS to analyze the potentially deposited discharge products. Furthermore, ICP-OES and FTIR techniques were employed for investigating the electrolytes to gain further insights into the possible mechanisms leading to cell discharge termination over time. Additionally, the possible reaction mechanisms governing within the cell were proposed for the Ti–air battery. Such a metal–air battery holds a unique potential to be the only metal with 4 electrons transfer during its discharge once its full potential is harvested.

A 4750 hours’ durability investigation of the PEMFC stack based on fuel cell hybrid vehicles conditions

ABSTRACT A novel protocol for testing the durability of proton exchange membrane fuel cell (PEMFC) stacks is developed using real-world road load data obtained from automobiles equipped with a PEMFC system manufactured by Weichai Power Company Limited, and the predetermined methodology is carried out for a cumulative duration of 4750 hours. The empirical results obtained from the durability test reveal that the average cell voltages (ACV) at specific current of 21 A, 105 A, 175 A, and 290 A exhibit degradation rates of 2%, 3.3%, 3.9%, and 10.9%, correspondingly. Furthermore,the polarization curve test results demonstrate ACV decay rates of 2.2% and 6.9% at 21 A and 360 A, respectively. The output voltage decay increases and the consistency of cells diminishes as the current rises. In comparison to the initial stage of the durability test, there is a slight decline in cell consistency observed toward the conclusion. In addition, a sensitivity test of the operational conditions is conducted at the 50th and 500th cycles, respectively. The findings reveal that the sensitivity to the cell consistency and output voltage remains largely stable throughout the durability test, and this suggests that the stack does not exhibit any noticeable alterations in its physicochemical characteristics.

A facile and economical approach to fabricate a single-piece bipolar plate for PEM electrolyzers

Water electrolysis will be an essential element of the future energy system, with hydrogen serving as a climate-friendly energy storage medium. To make electrolyzers suitable for market penetration at scale, the cost of manufacturing megawatt electrolyzers must be minimized, with no detrimental effects to their performance and lifetime. Here we show a facile and cost-effective manufacturing method to produce one-piece Ti-based bipolar plates. Low-cost and commercially and readily available feedstock materials (blank sheets, expanded metals and nonwovens) are positively joined using an innovative welding process, diffusion bonding. This approach reduces the contact resistances that can occur with multi-part bipolar plates by around 75%, reducing the number of components and therefore significantly simplifying stack assembly. Ex-situ tests on the contact pressure distribution on the active cell surface reveal a homogeneous pattern with values of about 3.75 MPa ( ± 1.25 MPa). In a first proof-of-concept, a five-cell short stack with a 100 cm2 active cell area, average cell voltages of 1.71 V at 2 A cm−2 could be achieved using our new stack concept.

Purification of crude indium by two-stage cyclone electrowinning

A possible process for the purification of crude indium by two-stage cyclone electrowinning was proposed. In accordance with a linear sweep voltammetry (LSV) results and the evaluation of the diffusion coefficient (D=6.15×10−11 cm2/s), indium electrodeposition in In2(SO4)3 solution was controlled by a diffusion-controlled irreversible process, and mass transfer can be significantly enhanced by electrolyte flow. During the 1st-stage indium cyclone electrowinning, a current efficiency (CE) of 80.15%, specific energy consumption (SEC) of 2.11 kW·h/kg and average cell voltage (ACV) of 2.04 V were achieved under the optimum conditions. Meanwhile, the purity of indium increased from 94.34% to 99.95%. During the 2nd-stage indium cyclone electrowinning, 98.95% purity of cathode indium was conducted by electrowinning under the optimum conditions, while the CE, SEC, and ACV were 75.23%, 2.23 kW·h/kg and 2.40 V, respectively. After two-stage cyclone electrowinning, the comprehensive recovery of indium is as high as 98.22%.

Selective butyric acid production from CO2 and its upgrade to butanol in microbial electrosynthesis cells

Microbial electrosynthesis (MES) is a promising carbon utilization technology, but the low-value products (i.e., acetate or methane) and the high electric power demand hinder its industrial adoption. In this study, electrically efficient MES cells with a low ohmic resistance of 15.7 mΩ m2 were operated galvanostatically in fed-batch mode, alternating periods of high CO2 and H2 availability. This promoted acetic acid and ethanol production, ultimately triggering selective (78% on a carbon basis) butyric acid production via chain elongation. An average production rate of 14.5 g m−2 d−1 was obtained at an applied current of 1.0 or 1.5 mA cm−2, being Megasphaera sp. the key chain elongating player. Inoculating a second cell with the catholyte containing the enriched community resulted in butyric acid production at the same rate as the previous cell, but the lag phase was reduced by 82%. Furthermore, interrupting the CO2 feeding and setting a constant pH2 of 1.7–1.8 atm in the cathode compartment triggered solventogenic butanol production at a pH below 4.8. The efficient cell design resulted in average cell voltages of 2.6–2.8 V and a remarkably low electric energy requirement of 34.6 kWhel kg−1 of butyric acid produced, despite coulombic efficiencies being restricted to 45% due to the cross-over of O2 and H2 through the membrane. In conclusion, this study revealed the optimal operating conditions to achieve energy-efficient butyric acid production from CO2 and suggested a strategy to further upgrade it to valuable butanol.

Integrated Biphasic Electrochemical Oxidation of Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid

Production of biobased platform chemicals and polymers via electrochemical routes enables the direct utilization of electrical energy from renewable sources. To date, the integration of electrochemical conversions in process chains remains largely unexplored, and the reactions are often studied using synthetic solutions. This work demonstrates the biphasic electro-oxidation of hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) and couples the electrochemical oxidation with the biphasic dehydration of fructose to HMF. The integrated approach eradicates the intermediate HMF purification as the HMF-rich organic product phase is fed directly into the electrochemical flow-cell reactor. Here, HMF is extracted into the aqueous phase and oxidized to FDCA on a Ni(OH)2/NiOOH catalyst in a 0.1 M KOH solution at pH 13. The FDCA then remains in the aqueous phase, enabling direct recirculation of the HMF-containing organic phase. We demonstrate a FDCA yield of close to 80% with a feed from HMF synthesis. Further, we analyze the influence of the phase ratio (organic to aqueous) and current density for biphasic electrochemical oxidation. By adjusting the gap width, we were able to decrease the average cell voltage from 7 V down to 3 V at a current density of 30 mA cm–1. This work presents a promising integrated process for the synthesis of green platform chemicals and provides insight into biphasic solutions in electrochemical conversions.

Recyclable 3D‐Printed Aqueous Lithium‐Ion Battery

Additive manufacturing, or 3D printing, in energy storage devices such as batteries has the potential to create new form factor small cells that are incorporated into the shape of the device at the design stage. With large‐scale proliferation, sustainable and recyclable materials are needed to avoid used cell waste accumulation, and the cells should have performance metrics that match or exceed existing cells. Inspired by safe aqueous battery chemistries and development in stereolithographic photopolymerization printing methods such as vat polymerization (Vat‐P), a 3D‐printed aqueous lithium‐ion battery developed, using sustainable active cathode and anode materials of LiMn2O4 and FePO4·2H2O, which can be fully recycled using a simple combustion method. This battery is designed to allow a stable cycling, higher energy density option compared to a metallic cell of similar construction, and to ensure better intraelectrode electrical conductivity and rigidity necessary for a viable cell, avoiding brittleness sometimes found in all‐in‐one composite‐printed electrodes. The printed cell has a stable cell‐level capacity of 1.86 mAh, better than that of a comparable metallic coin cell of similar internal chemistry, with an average cell voltage just over 1.0 V. Following combustion, the crystalline phase of LiMn2O4 and a mixed phase of some Fe2O3 mixed with a dominant composition of FePO4 are recovered. All inorganic materials are recovered after combustion.

Pengairan Sawah Tadah Hujan Gunakan Rekayasa Pompa Air Sistem Listrik Hybrid

Rainfed rice fields are agricultural areas whose irrigation systems depend on the rainy season. In the dry season, agricultural areas are not planted. The villagers make a living in the agricultural area. During the rainy season, some people cultivate crops, and during the dry season, some people turn to entrepreneurs or work in cities. This went on for years, and to deal with it, farmers built wells and used fossil fuel engines to pump the water. According to the case found in Duri Village, Slahung-Ponorogo District, the right technology is needed, namely hybrid electric water pump technology. A solution to the problem of irrigating rainfed rice fields. Engineering a solar power plant using hybrid electricity is an alternative option that can be implemented. Based on the results of the evaluation of this solar panel design, it produces 200 Wp of energy with an optimum voltage of 21.1 volts and a maximum current of 9.0 A. The optimum average solar cell voltage is 20.42V when it is hot and the charging voltage is 14.3V DC current. On cloudy days, the average voltage is 19.20 volts, and the charging voltage is 13.60 volts. Sunlight capacity is 8 hours per day, with normal full exposure of about 5 hours/day. Based on the review of the findings, it is necessary to increase the power supply capacity to a greater extent.. fossil fuel engines, water pump technology

Highly Conductive and Ultra Alkaline Stable Anion Exchange Membranes by Superacid-Promoted Polycondensation for Fuel Cells

A series of anion exchange membranes (4-QPPAF-TMA) were prepared by a metal-free, superacid-promoted polymerization reaction. The polymers were obtained with high molecular weight (Mn = 9.5–19.6 kDa, Mw = 44.9–622.5 kDa). 4-QPPAF-TMA membranes exhibited high hydroxide ion conductivity (up to 115 mS cm–1) at 80 °C, reasonable water absorbability (45% water uptake at 30 °C for 1.7 meq g–1), low to moderate dimensional swelling (5–15% at 30–80 °C for 1.7 meq g–1), and mechanical robustness (12.8 MPa maximum stress and 32% elongation at break for 1.7 meq g–1). Furthermore, 4-QPPAF-TMA membranes exhibited excellent alkaline stability in 8 M KOH at 80 °C for 1000 h, maintaining high conductivity (105 mS cm–1, 97% remaining). density functional theory (DFT) calculations suggested that the unique molecular configuration of the pendant ammonium head groups was responsible for high resistivity to the hydroxide ion attack. A fuel cell was operated with the 4-QPPAF-TMA membrane and an ionomer using a non-PGM cathode catalyst (Fe–N–C) to achieve a peak power density of 215 mW cm–2 accountable for 860 mW mg–1 Pt at a 590 mA cm–2 current density and 0.40 V (Pt–C cathode achieved 370 mW cm–1 at 810 mA cm–2 and 0.50 V). The fuel cell was operated at constant current density (15 mA cm–2) for 240 h with −0.79 mV h–1 average cell voltage decay. The postdurability analyses revealed that the membrane did not deteriorate while the degradation of the cathode catalysts/ionomer caused the performance loss.

Breaking the passivity wall of metals: Exempli gratia non-aqueous Ti–air battery

A new multivalent metal–air battery employing Titanium (Ti) as active material in EMIm(HF)2.3F room temperature ionic liquid electrolyte is introduced. Ti metal is highly attractive as it is a light metal that can possibly transfer up to 4 electrons. The electrochemical behavior of Ti is known for its passivity in various media. Here, we evaluated the electrochemistry of Ti in EMIm(HF)2.3F with potentiodynamic polarization and galvanostatic discharge experiments. Ti–air battery could successfully be operated under relatively high current densities (up to 0.75 mA cm−2) with an average cell voltage of 1–1.2 V, yielding up to a discharge capacity of 66mAhcm−2. When its full potential is harvested, such a metal–battery holds a unique potential to be the only metal with 4 electrons transfer during its discharge.