Multifunctional MOF-Derived Au, Co-Doped Porous Carbon Electrode for a Wearable Sweat Energy Harvesting-Storage Hybrid System

Metal-organic frameworks for high-performance cathodes in batteries

Metal-organic frameworks (MOFs) are functional materials that are proving to be indispensable for the development of next-generation batteries. The porosity, crystallinity, and abundance of active sites in MOFs, which can be tuned by selecting the appropriate transition metal/organic linker combination, enable MOFs to meet the performance requirements for cathode materials in batteries. Recent studies on the use of MOFs in cathodes have verified their high durability, cyclability, and capacity thus demonstrating the huge potential of MOFs as high-performance cathode materials. However, to keep pace with the rapid growth of the battery industry, several challenges hindering the development of MOF-based cathode materials need to be overcome. This review analyzes current applications of MOFs to commercially available lithium-ion batteries as well as advanced batteries still in the research stage. This review provides a comprehensive outlook on the progress and potential of MOF cathodes in meeting the performance requirements of the future battery industry.

In Situ Construction of NiCoMn-LDH Derived from Zeolitic Imidazolate Framework on Eggshell-Like Carbon Skeleton for High-Performance Flexible Supercapacitors

Active compounds based on LDH (ternary layered double hydroxide) are considered the perfect supercapacitor electrode materials on account of their superior electrochemical qualities and distinct structural characteristics, and flexible supercapacitors are an ideal option as an energy source for wearable electronics. However, the prevalent aggregation effect of LDH materials results in significantly compromised actual specific capacitance, which limits its broad practical applications. In this research, a 3D eggshell-like interconnected porous carbon (IPC) framework with confinement and isolation capability is designed and synthesized by using glucose as the carbon source to disperse the LDH active material and enhance the conductivity of the composite material. Second, by constructing NiCoMn-LDH nanocage structure based on ZIF-67 (zeolitic imidazolate framework-67) at the nanometer scale the obtained IPC/NiCoMn-LDH electrode material can expose more active sites, which allows to achieve excellent specific capacitance (2236 F g-1/ 310.6 mAh g-1 at 1 A g-1), good rate as well as the desired cycle stability (85.9% of the initial capacitance upon 5000 cycles test). The constructed IPC/NiCoMn-LDH//IPC ASC (asymmetric supercapacitor) exhibits superior capacitive property (135 F g-1/60.1 mAh g-1 at 0.5 A g-1) as well as desired energy density (40 Wh kg-1 at 800 W kg-1).

Design and Synthesis of Transferrable Macro-Sized Continuous Free-Standing Metal-Organic Framework Films for Biosensor Device

Metal organic framework (MOF) films have attracted abundant attention due to their unique characters compared with MOF particles. But the high-temperature reaction and solvent corrosion limit the preparation of MOF films on fragile substrates, hindering further applications. Fabricating macro-sized continuous free-standing MOF films and transferring them onto fragile substrates are a promising alternative but still challenging. Here, a universal strategy to prepare transferrable macro-sized continuous free-standing MOF films with the assistance of oxide nanomembranes prepared by atomic layer deposition and studied the growth mechanism is developed. The oxide nanomembranes serve not only as reactant, but also as interfacial layer to maintain the integrality of the free-standing structure as the stacked MOF particles are supported by the oxide nanomembrane. The centimeter-scale free-standing MOF films can be transferred onto fragile substrates, and all in one device for glucose sensing is assembled. Due to the strong adsorption toward glucose molecules, the obtained devices exhibit outstanding performance in terms of high sensitivity, low limit of detection, and long durability. This work opens a new window toward the preparation of MOF films and MOF film-based biosensor chip for advantageous applications in post-Moore law period.

Multi-functional integrated design of a copper foam-based cathode for high-performance lithium-oxygen batteries

Lithium-oxygen batteries (LOBs) with extraordinarily high energy density are some of the most captivating energy storage devices. Designing an efficient catalyst system that can minimize the energy barriers and address the oxidant intermediate and side-product issues is the major challenge regarding LOBs. Herein, we have developed a new type of integrated cathode of Cu foam-supported hierarchical nanowires decorated with highly catalytic Au nanoparticles which achieves a good combination of a gas diffusion electrode and a catalyst electrode, contributing to the synchronous multiphase transport of ions, oxygen, and electrons as well as improving the cathode reaction kinetics effectively. Benefiting from such a unique hierarchical architecture, the integrated cathode delivered superior electrochemical performance, including a high discharge capacity of up to 11.5 mA h cm-2 and a small overpotential of 0.49 V at 0.1 mA cm-2, a favorable energy efficiency of 84.3% and exceptional cycling stability with nearly 1200 h at 0.1 mA cm-2 under a fixed capacity of 0.25 mA h cm-2. Furthermore, density functional theory (DFT) calculations further reveal the intrinsic direct catalytic ability to form/decompose Li2O2 during the ORR/OER process. As a consequence, this work provides an insightful investigation on the structural engineering of catalysts and holds great potential for advanced integrated cathode design for LOBs.

A review of physical, chemical and biological synthesis methods of bimetallic nanoparticles and applications in sensing, water treatment, biomedicine, catalysis and hydrogen storage

This article provides an in-depth analysis of various fabrication methods of bimetallic nanoparticles (BNP), including chemical, biological, and physical techniques. The review explores BNP's diverse uses, from well-known applications such as sensing water treatment and biomedical uses to less-studied areas like breath sensing for diabetes monitoring and hydrogen storage. It cites results from over 1000 researchers worldwide and >300 peer-reviewed articles. Additionally, the article discusses current trends, actionable recommendations, and the importance of synthetic analysis for industry players looking to optimize manufacturing techniques for specific applications. The article also evaluates the pros and cons of various fabrication methods, highlighting the potential of plant extract synthesis for mass production of capped BNPs. However, it warns that this method may not be suitable for certain applications requiring ligand-free surfaces. In contrast, physical methods like laser ablation offer better control and reactivity, especially for applications where ligand-free surfaces are critical. The report underscores the environmental benefits of plant extract synthesis compared to chemical methods that use hazardous chemicals and pose risks to extraction, production, and disposal. The article emphasizes the need for life cycle assessment (LCA) articles in the literature, given the growing volume of research on nanotechnology materials. This article caters to researchers at all stages and applies to various fields applying nanomaterials.