Development of Zinc Slurry Air Flow Battery

Batteries have gained large interest in past few decades as energy storage systems because their merits such as relatively high efficiency, good durability of battery and unique power and energy output design. There are many types of batteries which can be used as reversible, or secondary, energy storage systems like redox flow batteries or metal-air batteries. The hybrid of those two types of batteries which is the Zinc slurry air flow battery uses zinc particles suspended in highly alkaline solution as the electrolyte and electrode for the negative compartment, whereas air is flowing in and out of the positive compartment for the oxygen reaction. As this is a relatively new concept of battery, there are two important factors which needs to be investigated. First, the discharge performance of the battery is the primary problem to be solved and the second challenge is the rechargeability of the battery to make it a secondary battery. In order to achieve those two goals, the bipolar plates are one of the key components to be studied in redox flow batteries as they require not only a good electrical conductivity, but also good mechanical durability with high corrosion resistance. Furthermore, this component is also important as the electrolyte flow can be improved by carving a flow field on the bipolar plate. Hence, this study aims first to improve the discharge performance of the Zinc Slurry Air Flow Battery. To do this, several types of flow field designs and material compositions have been tested as they play an important role in the performance of the redox flow battery, especially when using highly viscous liquids. To enhance the discharge power density of zinc slurry air flow batteries, an optimum slurry distribution in the cell is key. Hence, several types of flow fields (serpentine, parallel, plastic flow frames) were tested in this study to improve the discharge power density of the battery. The serpentine flow field delivered a power density of 55 mW·cm−2, while parallel and flow frame resulted in 30 mW·cm−2 and 10 mW·cm−2, respectively. Moreover, when the anode bipolar plate material was changed from graphite to copper, the power density of the flow frame increased to 65 mW·cm−2, and further improvement was attained when the bipolar plate material was further changed to copper–nickel. These results show the potential to increase the power density of slurry-based flow batteries by flow field optimization and design of bipolar plate materials. The second aim of this work is to improve the rechargeability of the battery. In the last section of this study, carbon additives were introduced to achieve a rechargeable zinc slurry flow battery by minimizing the zinc plating on the bipolar plate that occurs during charging. When no carbon additive was present in the zinc slurry, the discharge current density was 24mA·cm−2 at 0.6 V, while the use of carbon additives increased it to up to 38 mA·cm−2. The maximum power density was also increased from 16 mW·cm−2 to 23 mW·cm−2. Moreover, the amount of zinc plated on the bipolar plate during charging decreased with increasing carbon content in the slurry. A rheological investigation revealed that the elastic modulus and yield stress are directly proportional to the carbon content in the slurry, which is beneficial for redox flow battery applications, but comes at the expense of an increase in viscosity (two-fold increase at 100s−1). These results show how the use of conductive additives can enhance the energy density of slurry-based flow batteries

Use of Carbon Additives towards Rechargeable Zinc Slurry Air Flow Batteries

The performance of redox flow batteries is notably influenced by the electrolyte, especially in slurry-based flow batteries, as it serves as both an ionic conductive electrolyte and a flowing electrode. In this study, carbon additives were introduced to achieve a rechargeable zinc slurry flow battery by minimizing the zinc plating on the bipolar plate that occurs during charging. When no carbon additive was present in the zinc slurry, the discharge current density was 24 mA∙cm$^{-2}$ at 0.6 V, while the use of carbon additives increased it to up to 38 mA∙cm$^{-2}$. The maximum power density was also increased from 16 mW∙cm$^{-2}$ to 23 mW∙cm$^{-2}$. Moreover, the amount of zinc plated on the bipolar plate during charging decreased with increasing carbon content in the slurry. Rheological investigation revealed that the elastic modulus and yield stress are directly proportional to the carbon content in the slurry, which is beneficial for redox flow battery applications, but comes at the expense of an increase in viscosity (two-fold increase at 100 s$^{-1}$). These results show how the use of conductive additives can enhance the energy density of slurry-based flow batteries

Pristine and modified porous membranes for zinc slurry–air flow battery

The membrane is a crucial component of Zn slurry–air flow battery since it provides ionic conductivity between the electrodes while avoiding the mixing of the two compartments. Herein, six commercial membranes (Cellophane™ 350PØØ, Zirfon®, Fumatech® PBI, Celgard® 3501, 3401 and 5550) were first characterized in terms of electrolyte uptake, ion conductivity and zincate ion crossover, and tested in Zn slurry–air flow battery. The peak power density of the battery employing the membranes was found to depend on the in-situ cell resistance. Among them, the cell using Celgard® 3501 membrane, with in-situ area resistance of 2 Ω cm$^{2}$ at room temperature displayed the highest peak power density (90 mW cm−2). However, due to the porous nature of most of these membranes, a significant crossover of zincate ions was observed. To address this issue, an ion-selective ionomer containing modified poly(phenylene oxide) (PPO) and N-spirocyclic quaternary ammonium monomer was coated on a Celgard® 3501 membrane and crosslinked via UV irradiation (PPO-3.45 + 3501). Moreover, commercial FAA-3 solutions (FAA, Fumatech) were coated for comparison purpose. The successful impregnation of the membrane with the anion-exchange polymers was confirmed by SEM, FTIR and Hg porosimetry. The PPO-3.45 + 3501 membrane exhibited 18 times lower zincate ions crossover compared to that of the pristine membrane (5.2 × 10$^{-13}$ vs. 9.2 × 10$^{-12}$ m$^{2}$ s$^{-1}$). With low zincate ions crossover and a peak power density of 66 mW cm$^{-2}$, the prepared membrane is a suitable candidate for rechargeable Zn slurry–air flow batteries

Economic evaluation with sensitivity and profitability analysis for hydrogen production from water electrolysis in Korea

Economic evaluation for water electrolysis compared to steam methane reforming has been carried out in terms of unit hydrogen production cost analysis, sensitivity analysis, and profitability analysis to assess current status of water electrolysis in Korea. For a hydrogen production capacity of 30 Nm(3) h(-1), the unit hydrogen production cost was 17.99, 16.54, and 20.18 $kg H-2(-1) for alkaline water electrolysis (AWE), PEM water electrolysis (PWE), and steam methane reforming (SMR), respectively with 11.24, 10.66, and 11.80 for 100 Nm(3) h(-1) and 8.12, 7.72, and 7.59$kg H-2(-1) for 300 Nm(3) h(-1). With sensitivity analysis (SA), the most influential factors on the unit hydrogen production cost depending on the hydrogen production capacity were determined. Lastly, profitability analysis (PA) presented a discounted payback period (DPBP), net present value (NPV), and present value ratio (PVR) for a different discount rate ranging from 2 to 14% and it was found that a discounted cash flow rate of return (DCFROR) was 14.01% from a cash flow diagram obtained for a hydrogen production capacity of 30 Nm(3) h(-1)

Economic evaluation with uncertainty analysis using a Monte-Carlo simulation method for hydrogen production from high pressure PEM water electrolysis in Korea

Economic analysis with uncertainty analysis based on a Monte-Carlo simulation method was performed for hydrogen production from high pressure PEM water electrolysis targeting a hydrogen production capacity of 30 Nm(3) h(-1) in Korea. With key economic parameters obtained from sensitivity analysis (SA), a cumulative probability curve was constructed for a unit H-2 production cost fully reflecting unpredictable price fluctuations in H-2 production equipment, construction, electricity, and labor from +/- 10% to +/- 50%. In addition, economic analysis for a net present value (NPV) with uncertainty analysis for revenue (REV), fixed capital investment (FCI), and cost of manufacturing (COM) provided cumulative probability curves with different discount rates and more reliable NPVs (-$69,000 similar to$1,308,000) for high pressure PEM water electrolysis under development in Korea. This economic analysis based on uncertainty can serve as important economic indicators suitable for premature technology like high pressure PEM water electrolysis currently being in progress in Korea

Anion Exchange Membranes Incorporating Multi N -Spirocyclic Quaternary Ammonium Cations via Ultraviolet-Initiated Polymerization for Zinc Slurry-Air Flow Batteries

International audienc

Use of Carbon Additives towards Rechargeable Zinc Slurry Air Flow Batteries

International audienceThe performance of redox flow batteries is notably influenced by the electrolyte, especially in slurry-based flow batteries, as it serves as both an ionic conductive electrolyte and a flowing electrode. In this study, carbon additives were introduced to achieve a rechargeable zinc slurry flow battery by minimizing the zinc plating on the bipolar plate that occurs during charging. When no carbon additive was present in the zinc slurry, the discharge current density was 24 mA•cm −2 at 0.6 V, while the use of carbon additives increased it to up to 38 mA•cm −2. The maximum power density was also increased from 16 mW•cm −2 to 23 mW•cm −2. Moreover, the amount of zinc plated on the bipolar plate during charging decreased with increasing carbon content in the slurry. Rheological investigation revealed that the elastic modulus and yield stress are directly proportional to the carbon content in the slurry, which is beneficial for redox flow battery applications, but comes at the expense of an increase in viscosity (two-fold increase at 100 s −1). These results show how the use of conductive additives can enhance the energy density of slurry-based flow batteries

Ultrahigh-Resolution Full-Color Perovskite Nanocrystal Patterning for Ultrathin Skin-Attachable Displays

High-definition red/green/blue (RGB) pixels and deformable form factors are essential for the next-generation advanced displays. Here, we present ultrahigh-resolution full-color perovskite nanocrystal (PeNC) patterning for ultrathin wearable displays. Double-layer transfer printing of the PeNC and organic charge transport layers is developed, which prevents internal cracking of the PeNC film during the transfer printing process. This results in RGB pixelated PeNC patterns of 2550 pixels per inch (PPI) and monochromic patterns of 33,000 line pairs per inch with 100% transfer yield. The perovskite light-emitting diodes (PeLEDs) with transfer-printed active layers exhibit outstanding electroluminescence characteristics with remarkable external quantum efficiencies (15.3, 14.8, and 2.5% for red, green, and blue, respectively), which are high compared to the printed PeLEDs reported to date. Furthermore, double-layer transfer printing enables the fabrication of ultrathin multicolor PeLEDs that can operate on curvilinear surfaces, including human skin, under various mechanical deformations. These results highlight that PeLEDs are promising for high-definition full-color wearable displays.11Nsciescopu