Enhanced oxygen evolution performance of spinel Fe0.1Ni0.9Co2O4/Activated carbon composites

Enhanced oxygen evolution and power density of Co/Zn@NC@MWCNTs for the application of zinc-air batteries

Rechargeable zinc-air batteries (ZABs) are viewed as a promising solution for electric vehicles due to their potential to provide a clean, cost-effective, and sustainable energy storage system for the next generation. Nevertheless, sluggish kinetics of the oxygen evolution reaction (OER), the oxygen reduction reaction (ORR) at the air electrode, and low power density are significant challenges that hinder the practical application of ZABs. The key to resolving the development of ZABs is developing an affordable, efficient, and stable catalyst with bifunctional catalytic. In this study, we present a series of bifunctional catalysts composed of Co/Zn nanoparticles uniformly embedded in nitrogen-doped carbon (NC) and multi-walled carbon nanotubes (MWCNTs) denoted as Co/Zn@NC@MWCNTs. The incorporation of MWCNTs using a facile and non-toxic method significantly decreased the overpotential of the OER from 570 to 430 mV at 10 mA cm-2 and the peak power density from 226 to 263 mW cm-2. Besides, the electrochemical surface area measurements and electrochemical impedance spectroscopy indicate that the three-dimensional (3D) network structure of MWCNTs facilitates mass transport for ORR and reduces electron transfer resistance during OER, leading to a small potential gap of 0.86 V between OER and ORR, high electron transfer number (3.92-3.98) of the ORR, and lowest Tafel slope (47.8 mV dec-1) of the OER in aqueous ZABs. In addition, in-situ Raman spectroscopy revealed a notable decrease in the ID/IG ratio for the optimally configured Co/Zn@NC@MWCNTs (75:25), indicating a reduction in defect density and improved structural ordering during the electrochemical process, which directly contributes to enhanced ORR activity. Hence, this study provides an excellent strategy for constructing a bifunctional catalyst material with a 3D MWCNTs conductive network for the development of advanced ZAB systems for sustainable energy applications.

Recent Advances in Catalyst Design and Performance Optimization of Nanostructured Cathode Materials in Zinc-Air Batteries

This review focuses on the advanced design and optimization of nanostructured zinc-air batteries (ZABs), with the aim of boosting their energy storage and conversion capabilities. The findings show that ZABs favor porous nanostructures owing to their large surface area, and this enhances the battery capacity, catalytic activity, and life cycle. In addition, the nanomaterials improve the electrical conductivity, ion transport, and overall battery stability, which crucially reduces dendrite growth on the zinc anodes and improves cycle life and energy efficiency. To obtain a superior performance, the importance of controlling the operational conditions and using custom nanostructural designs, optimal electrode materials, and carefully adjusted electrolytes is highlighted. In conclusion, porous nanostructures and nanoscale materials significantly boost the energy density, longevity, and efficiency of Zn-air batteries. It is suggested that future research should focus on the fundamental design principles of these materials to further enhance the battery performance and drive sustainable energy solutions.

Application of Conductive MOF in Zinc-Based Batteries

The use of conductive MOFs (c-MOFs) in zinc-based batteries has been a popular research direction. Zinc-based batteries are widely used with the advantages of high specific capacity and safety and stability, but they also face many problems. c-MOFs have excellent conductivity compared with other primitive MOFs, and therefore have better applications in zinc-based batteries. In this paper, the transfer mechanisms of the unique charges of c-MOFs: hop transport and band transport, respectively, are discussed and the way of electron transport is further addressed. Then, the various ways to prepare c-MOFs are introduced, among which solvothermal, interfacial synthesis, and postprocessing methods are widely used. In addition, the applications of c-MOFs are discussed in terms of their role and performance in different types of zinc-based batteries. Finally, the current problems of c-MOFs and the prospects for their future development are presented.

MOFs Containing Solid-State Electrolytes for Batteries

The use of metal-organic frameworks (MOFs) in solid-state electrolytes (SSEs) has been a very attractive research area that has received widespread attention in the modern world. SSEs can be divided into different types, some of which can be combined with MOFs to improve the electrochemical performance of the batteries by taking advantage of the high surface area and high porosity of MOFs. However, it also faces many serious problems and challenges. In this review, different types of SSEs are classified and the changes in these electrolytes after the addition of MOFs are described. Afterward, these SSEs with MOFs attached are introduced for different types of battery applications and the effects of these SSEs combined with MOFs on the electrochemical performance of the cells are described. Finally, some challenges faced by MOFs materials in batteries applications are presented, then some solutions to the problems and development expectations of MOFs are given.

Recent Progress of Non-Noble Metal Catalysts for Oxygen Electrode in Zn-Air Batteries: A Mini Review

Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play crucial roles in energy conversion and storage devices. Particularly, the bifunctional ORR/OER catalysts are core components in rechargeable metal–air batteries, which have shown great promise in achieving "carbon emissions peak and carbon neutrality" goals. However, the sluggish ORR and OER kinetics at the oxygen cathode significantly hinder the performance of metal–air batteries. Although noble metal-based catalysts have been widely employed in accelerating the kinetics and improving the bifunctionality, their scarcity and high cost have limited their deployment in the market. In this review, we will discuss the ORR and OER mechanisms, propose the principles for bifunctional electrocatalysts design, and present the recent progress of the state-of-the-art bifunctional catalysts, with the focus on non-noble metal-based materials to replace the noble metal catalysts in Zn–air batteries. The perspectives for the future R&D of bifunctional electrocatalysts will be provided toward high-performance Zn–air batteries at the end of this paper.