Interfacial Electronic Modulation in Synergistic FeNi–FeNC Hybrid Catalysts with Tuned d-Band Centers for Efficient and Durable Zinc–Air Batteries

Developing electrocatalysts that integrate the merits of the hollow structure and heterojunction is an attractive but still challenging strategy for addressing the sluggish kinetics of oxygen evolution reaction (OER) in many renewable energy technologies. Herein, a 3D hierarchically flexible self-supporting electrode with a hollow heterostructure is intentionally constructed by assembling thin NiFe layered double hydroxide (LDH) nanosheets on the surface of metal-organic framework-derived hollow NiCo2O4 nanoflake arrays (NiCo2O4@NiFe-LDH) for rechargeable Zn-air batteries (ZABs). Theoretical calculations demonstrate that the interfacial electron transfer from NiFe-LDH to NiCo2O4 induces the electronic modulation, improves the conductivity, and lowers the reaction energy barriers during OER, ensuring high catalytic activity. Meanwhile, the 3D hierarchically hollow nanoarray architecture can afford plentiful catalytic active sites and short mass-/charge-transfer pathways. As a result, the obtained catalyst exhibits remarkable OER electrocatalytic performance, showing low overpotentials (only 231 mV at 10 mA cm-2, 300 mV at 50 mA cm-2) and robust stability. When assembling liquid and flexible solid-state ZABs with NiCo2O4@NiFe-LDH as the OER catalyst, the ZABs achieve excellent power density, high specific capacity, superior cycle durability, and good bending flexibility, exceeding the RuO2 + Pt/C benchmarks and other previously reported self-supporting catalysts. This work not only constructs an advanced hollow heterostructured catalyst for sustainable energy systems and wearable electronic devices but also provides insights into the role of interfacial electron modulation in catalytic performance enhancement.

Rationally designing and developing robust and durable electrocatalytic materials for oxygen reduction/evolution are essential for metal−air batteries. Herein, an effective approach is proposed to fabricate high-performance electrocatalysts based on CoFe alloy and CoC X nanoparticles sandwiched in nitrogen-doped carbon nanotubes. The preparation of CoFe−CoC X @NCNT is achieved by the calcination of CoFe 2 O 4 spinel and dicyandiamide under reducing atmosphere. The CoFe−CoC X @NCNT catalyst exhibits remarkable oxygen reduction reaction (ORR) performance with the onset and half-wave potential of 1.01 ​V and 0.89 ​V, respectively, exceeding the commercial Pt/C catalyst. Furthermore, the Zn−air battery using CoFe−CoC X @NCNT as air cathode shows a power density of 175 ​mW ​cm −2 , which is also higher than that of the industrial Pt/C ​+ ​RuO 2 . The super electrocatalytic performance is attributed to the multiple heterointerface and strong coupling effect among CoFe, CoC X , and NCNT, which can regulate conductivity and electron structure of the catalyst. This study supplies a practical strategy to exploit active and low-cost catalytic material for Zn−air batteries, and presents an in-depth insight into the designing of efficient green energy storage devices. Herein, the CoFe-CoC X @NCNT exhibits an outstanding ORR performance with onset potential of 1.01 ​V and half-wave potential of 0.89 ​V, exceeding the commercial Pt/C catalyst. Furthermore, the Zn-air battery performance assembled by CoFe-CoC X @NCNT shows the power density of 175 ​mW ​cm −2 is also better than that of the commercial Pt/C ​+ ​RuO 2 . The excellent performance is attributed to the multiple heterogeneous interfaces and strong coupling between CoFe alloy, CoC X , and NCNT, which are helpful to drive fast reaction kinetics and regulate local coordination environment and electronic structure. This work provides a new approach to design excellent active and low-cost catalysts for Zn-air batteries, which presents an in-depth insight into the development of efficient green energy storage devices.

Zinc systems | Zinc–air

Incorporating intermittent renewable energy sources into the power grid will require large amounts of grid-scale energy storage. Electrochemical batteries are a versatile and scalable energy storage option and, hence, Li-ion batteries have been widely adopted to store excess wind and solar energy [1]. Li-ion batteries, however, have a relatively low energy density and serious safety concerns. An alternative electrochemical battery option lies with zinc-air batteries. This technology uses lower cost materials and is overall much safer. Furthermore, zinc-air batteries have a much larger theoretical energy density than Li-ion batteries [2]. The major impediment to wide-scale adoption of zinc-air batteries is the low energy efficiency because of the poor reaction kinetics at the air electrode. Both the charge and discharge reactions at the air electrode are sluggish and require the use of catalysts to obtain practicable performance. However, many catalysts active towards the charge reaction are not active towards the discharge reaction, and vice versa. The development of a catalyst active towards both the charge and discharge reactions, known as a bifunctional catalyst, is therefore a high priority [3]. Furthermore, catalysts employed in zinc-air batteries often show instability, with performance degradation evident after a few cycles. Ultimately, a highly stable bifunctional zinc-air battery catalyst is of the utmost importance.The aim of this work is to develop highly stable bifunctional catalysts for zinc-air batteries using atomic layer deposition (ALD). With ALD, extremely conformal catalyst coatings can be deposited directly on the air electrode of a zinc-air battery. The self-limiting surface reactions of ALD ensure that electrode porosity is maintained while maximizing the total coating surface area [4]. Since ALD operates in the gas phase, catalytic coatings can be deposited deep within the pores of the air electrode. This will help maintain the three-phase boundary necessary for the discharge reaction and ultimately improve the stability of a zinc-air battery [5]. To create a bifunctional catalyst, two ALD processes, one for manganese oxide and another for iron oxide, is combined into one ALD supercycle, depositing a mixed manganese-iron oxide. Since manganese oxide is a well-established discharge catalyst [6], and iron oxide demonstrates activity towards the charge reaction [7], this mixed manganese-iron oxide exhibits bifunctional activity in a zinc-air battery. An optimized supercycle process will be discussed and full-cell battery test results showcased. Specifically, the bifunctional efficiency of a zinc-air battery can be improved by more than 10% by using the mixed manganese-iron oxide catalyst. In addition, the high stability of the manganese-iron oxide catalyst is demonstrated, where bifunctional efficiency can be maintained at over 95% of the initial value over 200 cycles. Materials characterization of the mixed manganese-iron oxide, deposited through ALD, is also included.[1] L. Trahey, F. R. Brushett, N. P. Balsara, G. Ceder, L. Cheng, Y. M. Chiang, N. T. Hahn, B. J. Ingram, S. D. Minteer, J. S. Moore, K. T. Mueller, L. F. Nazar, K. A. Persson, D. J. Siegel, K. Xu, K. R. Zavadil, V. Srinivasan, and G. W. Crabtree, “Energy Storage Emerging: A Perspective from the Joint Center for Energy Storage Research,” Proc. Natl. Acad. Sci. U. S. A., vol. 117, no. 23, pp. 12550–12557, 2020.[2] J. Fu, R. Liang, G. Liu, A. Yu, Z. Bai, L. Yang, and Z. Chen, “Recent Progress in Electrically Rechargeable Zinc – Air Batteries,” Adv. Mater., vol. 31, no. 31, p. 1805230, 2019.[3] E. Davari and D. G. Ivey, “Bifunctional electrocatalysts for Zn – air batteries,” Sustain. Energy Fuels, vol. 2, no. 1, pp. 39–67, 2018.[4] C. Detavernier, J. Dendooven, S. Pulinthanathu Sree, K. F. Ludwig, and J. A. Martens, “Tailoring nanoporous materials by atomic layer deposition,” Chem. Soc. Rev., vol. 40, no. 11, pp. 5242–5253, 2011.[5] M. P. Clark, M. Xiong, K. Cadien, and D. G. Ivey, “High Performance Oxygen Reduction/Evolution Electrodes for Zinc − Air Batteries Prepared by Atomic Layer Deposition of MnOx,” ACS Appl. Energy Mater., vol. 3, no. 1, pp. 603–313, 2020.[6] M. P. Clark, T. Muneshwar, M. Xiong, K. Cadien, and D. G. Ivey, “Saturation Behavior of Atomic Layer Deposition MnOx from Bis(Ethylcyclopentadienyl) Manganese and Water: Saturation Effect on Coverage of Porous Oxygen Reduction Electrodes for Metal-Air Batteries,” ACS Appl. Nano Mater., vol. 2, no. 1, pp. 267–277, 2019.[7] M. Labbe, M. P. Clark, Z. Abedi, A. He, K. Cadien, and D. G. Ivey, “Atomic layer deposition of iron oxide on a porous carbon substrate via ethylferrocene and an oxygen plasma,” Surf. Coatings Technol., vol. 421, p. 127390, 2021.

Interfacial electronic modulation on heterostructured NiSe@CoFe LDH nanoarrays for enhancing oxygen evolution reaction and water splitting by facilitating the deprotonation of OH to O

A unique disposable invasive hemodynamic blood pressure transducer system has been developed. The system consists of a disposable piezoresistive flow-through transducer with twelve-inch pigtail, a reusable extension cable, an electronic interface module and a custom interconnect cable to attach to most monitors. The transducer has Linden Luer fittings and replaces the dome and reusable transducer in monitoring systems. The cost of the transducer is kept low so that it can be disposable through efficient modern, high-volume semiconductor technology and the fact that additional electrical isolation is accomplished in the interface module. Besides providing electrical isolation, the interface module provides a universal output which will accommodate all common AC, DC, and pulsed excitation signals from monitors.

MOF derived Co–Mo2C heterojunctions with interfacial electronic modulation for oxygen reduction reaction and zinc–air batteries

Perovskite‐based catalysts have received a lot attention as bifunctional oxygen evolution reaction and oxygen reduction reaction (ORR/OER) catalysts in secondary rechargeable zinc–air batteries due to their tunable structure, stability at high current densities, low cost, lightweight, and nontoxicity. This paper investigates a new perovskite material, Sr2TiMnO6 (STMO), for a rechargeable zinc–air battery (ZAB). The crystalline structure, morphology, and adsorption/desorption behavior of STMO are thoroughly studied and investigated their catalytic processes. The perovskite catalyst shows high catalytic activities, durability, and endurance in the alkaline medium, resulting in the power density of 97 mW·cm−2, and a specific capacity of 705.21 mAh·g−1. The rechargeable STMO ZAB exhibited good cycling stability with the current density of 3.5 mA·cm−2 for 6.66 h and low overpotential. The observed results promise STMO to be a viable candidate as a functional (ORR/OER) electrocatalyst which can be successfully used for commercial fuel‐cells and metal air batteries.

The rational construction of efficient bifunctional oxygen electrocatalysts is of immense significance yet challenging for rechargeable metal–air batteries. Herein, this work reports a metal–organic framework derived 2D nitrogen‐doped carbon nanotubes/graphene hybrid as the efficient bifunctional oxygen electrocatalyst for rechargeable zinc–air batteries. The as‐obtained hybrid exhibits excellent catalytic activity and durability for the oxygen electrochemical reactions due to the synergistic effect by the hierarchical structure and heteroatom doping. The assembled rechargeable zinc–air battery achieves a high power density of 253 mW cm−2 and specific capacity of 801 mAh gZn−1 with excellent cycle stability of over 3000 h at 5 mA cm−2. Moreover, the flexible solid‐state rechargeable zinc–air batteries assembled by this hybrid oxygen electrocatalyst exhibits a high discharge power density of 223 mW cm−2, which can power 45 light‐emitting diodes and charge a cellphone. This work provides valuable insights in designing efficient bifunctional oxygen electrocatalysts for long‐life metal–air batteries and related energy conversion technologies.

Drones or mini-unmanned aerial vehicles, have becoming an emerging trends due to their boundless applications in surveillance, military and numerous public services. Nowadays, deployment of surveillance drone for monitoring or security application remains challenging and ongoing research. As Internet of Things (IoT) becomes more commercialized, various concept of IoT have been integrated with the drones due to efficient usage. Therefore, this paper proposed the development of surveillance drone system based on IoT for industrial monitoring-security applications. The rationale of integrating IoT with surveillance drone is that it allows authenticated users to login from any device, anywhere, and view video or images from surveillance drones in real-time for security awareness. In this work, the surveillance drone consists of mechanical system, electrical and electronic interfacing and IoT platform (mobile application system). In electronic system, power module, communication module, sensor and actuator as well as user interface module have been adopted and integrated into the systems. Besides, in software development system, user interface configuration was developed through mobile application to serve as IoT platform. A series of experiments shows that the surveillance drone based IoT able to operate with a promising flying distance with surveillance camera as the “eyes” of the drone system.

Robotic grippers have becoming an emerging trend due to their boundless applications in industrial automation. Nowadays, the deployment of vision based smart gripper for material handling in industrial applications remains challenging and ongoing research. As the Internet of Things (IoT) becomes more commercialized, the various concept of IoT have been integrated with the gripper due to efficient usage. Therefore, this project proposes the development of vision-based sensor of smart gripper for material handling in industrial applications that integrates with the IoT. The rationale of integrating IoT to vision based smart gripper is that it allows authenticated users to log in from any device, anywhere, and view video or images from vision based smart gripper in real-time for critical material handling. This system incorporates a vision sensor camera that acts as an “eye” to automatically detect and recognize the object with different weights and shapes and send the information to the robot for the next task. This smart gripper adopts a force sensor mounted into the fingertip to control the force applied when working with a wide range of objects with different weights. As for the electronic system, power module, communication and control module, sensor and actuator as well as user interface module have been adopted and integrated into the system. In the software development system, user interface configuration was developed through mobile application in which it communicates with Raspberry Pi B+ camera to serve as IoT platform. A series of experiments shows that the vision based gripper using IoT able to detect and recognize the objects and then send the information/command directly to the robot to execute grasping and lifting phase of the object to the desired location that has been assigned.

P-doping optimized d-band center position in MoO2 with enhanced oxygen reduction reaction and oxygen evolution reaction activities for rechargeable Zn-air battery

Facing the challenges of energy crisis and global warming, the development of renewable energy has received more and more attention. To offset the discontinuity of renewable energy, such as wind and solar energy, it is urgent to search for an excellent performance energy storage system to match them. Metal-air batteries (typical representative: Li-air battery and Zn-air battery) have broad prospects in the field of energy storage due to their high specific capacity and environmental friendliness. The drawbacks preventing the massive application of metal-air batteries are the poor reaction kinetics and high overpotential during the charging-discharging process, which can be alleviated by the application of an electrochemical catalyst and porous cathode. Biomass, also, as a renewable resource, plays a critical role in the preparation of carbon-based catalysts and porous cathode with excellent performance for metal-air batteries due to the inherent rich heteroatom and pore structure of biomass. In this paper, we have reviewed the latest progress in the creative preparation of porous cathode for the Li-air battery and Zn-air battery from biomass and summarized the effects of various biomass sources precursors on the composition, morphology and structure-activity relationship of cathode. This review will help us understand the relevant applications of biomass carbon in the field of metal-air batteries.

Automated system for neutron activation analysis determination of short lived isotopes at The DOW Chemical Company's TRIGA research reactor

Due to severe energy crisis and environmental problems, green and renewable electrochemical energy devices such as fuel cells and metal–air batteries have attracted great attention, where oxygen reduction reaction (ORR) plays a vital role. The rational design of efficient and robust single‐atom catalysts (SACs) is vital but challenging toward ORR. Here, recent developments of single‐atom ORR catalysts in fuel cells and Zn–air batteries are systematically summarized, focusing on transition‐metal‐based electrocatalysts including single or dual Fe, Co, Ni, Cu, Zn, Pd, Ag, and Pt sites. At the atomic level, different synthesis methods and characterization techniques are introduced. Theoretical studies of ORR mechanisms are documented. The active sites and structure–property relationships of SACs for ORR are highlighted, and the performances of proton exchange membrane fuel cells (PEMFCs), anion exchange membrane fuel cells (AEMFCs), and Zn–air batteries are discussed. The great challenges and future directions of SACs in fuel cells and Zn–air batteries are presented.