Lina Chen

Additive manufacturing (AM), also known as 3D printing, has emerged as a transformative technology in various industries, providing unprecedented design freedom and customized manufacturing solutions. This paper presents a detailed exploration of additive manufacturing applications in metallic materials, introducing the various types of additive manufacturing technologies, elucidating their fundamental principles, and summarizing current research endeavors. The manuscript offers insights into future directions and challenges in this rapidly evolving field, serving as a valuable resource for researchers and engineers aiming to harness the potential of additive manufacturing in advancing metallic materials.

Aqueous zinc batteries, mainly including Zn-ion batteries (ZIBs) and Zn–air batteries (ZABs), are promising energy storage systems, but challenges exist at their current stage. For instance, the zinc anode in aqueous electrolyte is impacted by anodic dendrites, hydrogen and oxygen precipitation, and some other harmful side reactions, which severely affect the battery’s lifespan. As for traditional cathode materials in ZIBs, low electrical conductivity, slow Zn²⁺ ion migration, and easy collapse of the crystal structure during ion embedding and migration bring challenges. Also, the slower critical oxygen reduction reaction (ORR), for example, in ZABs shows unsatisfactory results. All these issues greatly hindered the development of zinc batteries. Aerogel materials, characterized by their high specific surface area, unique open-pore structure formed by nanoporous structures, and excellent physicochemical properties, have a positive role in cathode modification, electrode protection, and catalytic reactions in zinc batteries. This manuscript provides a systematic review of aerogel materials, highlighting advancements in their preparation and application for zinc batteries, aiming to promote the future progress and development of aerogel nanomaterials and zinc batteries.

Electrochemical CO₂ reduction in acidic media attracts extensive research attention due to its potential in increasing carbon efficiency. In most reports, alkali cations are introduced to suppress hydrogen evolution and to promote CO₂ reduction. However, the mass transport of alkali cations through cation exchange membrane induces the change of electrolyte compositions. Herein, the variation of electrolyte compositions and the flow of carbon during CO₂ reduction are analyzed quantitatively by simulation and experiments. If the initial amount of alkali cations in the anolyte is higher than the initial amount of H⁺ in the catholyte, the pH of the catholyte increases remarkably in long‐term CO₂ reduction electrolysis, resulting in the decrease of carbon efficiency. Bicarbonate salt precipitation on the cathode with alkali cation‐containing catholyte is another origin of the decrease of CO₂ reduction Faradaic efficiency and carbon efficiency. To maintain high carbon efficiency, the electrolyte should contain low concentration of alkali cations or even be free of alkali cations. Decorating the catalyst of cathode with ionomer with high density of cation sites enables CO₂ reduction in pure acid solution, achieving 30‐h stable carbon efficiency.

This article reviews the research and development focus of metallic glasses in the field of biomedical applications. Metallic glasses exhibit a short-range ordered and long-range disordered glassy structure at the microscopic level, devoid of structural defects such as dislocations and grain boundaries. Therefore, they possess advantages such as high strength, toughness, and corrosion resistance, combining characteristics of both metals and glasses. This novel alloy system has found applications in the field of biomedical materials due to its excellent comprehensive performance. This review discusses the applications of Ti-based bulk metallic glasses in load-bearing implants such as bone plates and screws for long-term implantation. On the other hand, Mg-based metallic glasses, owing to their degradability, are primarily used in degradable bone nails, plates, and vascular stents. However, metallic glasses as biomaterials still face certain challenges. The Young’s modulus value of Ti-based metallic glasses is higher than that of human bones, leading to stress-shielding effects. Meanwhile, Mg-based metallic glasses degrade too quickly, resulting in the premature loss of mechanical properties and the formation of numerous bubbles, which hinder tissue healing. To address these issues, we propose the following development directions: (1) Introducing porous structures into titanium-based metallic glasses is an important research direction for reducing Young’s modulus; (2) To enhance the bioactivity of implant material surfaces, the surface modification of titanium-based metallic glasses is essential. (3) Developing antibacterial coatings and incorporating antibacterial metal elements into the alloys is essential to maintain the long-term effective antibacterial properties of metallic biomaterials. (4) Corrosion resistance must be further improved through the preparation of composite materials, while ensuring biocompatibility and safety, to achieve controllable degradation rates and degradation modes.

Sodium-ion batteries (SIBs) have been proposed as a potential substitute for commercial lithium-ion batteries due to their excellent storage performance and cost-effectiveness. However, due to the substantial radius of sodium ions, there is an urgent need to develop anode materials with exemplary electrochemical characteristics, thereby enabling the fabrication of sodium-ion batteries with high energy density and rapid dynamics. Carbon materials are highly valued in the energy-storage field due to their diverse structures, low cost, and high reliability. This review comprehensively summarizes the typical structure; energy-storage mechanisms; and current development status of various carbon-based anode materials for SIBs, such as hard carbon, soft carbon, graphite, graphene, carbon nanotubes (CNTs), and porous carbon materials. This review also provides an overview of the current status and future development of related companies for sodium-ion batteries. Furthermore, it offers a summary and outlook on the challenges and opportunities associated with the design principles and large-scale production of carbon materials with high-energy-density requirements. This review offers an avenue for exploring outstanding improvement strategies for carbon materials, which can provide guidance for future application and research.

Nickel-based catalysts are regarded as the most excellent urea oxidation reaction (UOR) catalysts in alkaline media. Whatever kind of nickel-based catalysts is utilized to catalyze UOR, it is widely believed that the in situ-formed Ni³⁺ moieties are the true active sites and the as-utilized nickel-based catalysts just serve as pre-catalysts. Digging the pre-catalyst effect on the activity of Ni³⁺ moieties helps to better design nickel-based catalysts. Herein, five different anions of OH⁻, CO₃²⁻, SiO₃²⁻, MoO₄²⁻, and WO₄²⁻ were used to bond with Ni²⁺ to fabricate the pre-catalysts β-Ni(OH)₂, Ni-CO₃, Ni-SiO₃, Ni-MoO₄, and Ni-WO₄. It is found that the true active sites of the five as-fabricated catalysts are the same in situ-formed Ni³⁺ moieties and the five as-fabricated catalysts demonstrate different UOR activity. Although the as-synthesized five catalysts just serve as the pre-catalysts, they determine the quantity of active sites and activity per active site, thus determining the catalytic activity of the catalysts. Among the five catalysts, the amorphous nickel tungstate exhibits the most superior activity per active site and can catalyze UOR to reach 158.10 mA·cm^–2 at 1.6 V, exceeding the majority of catalysts. This work makes for a deeper understanding of the pre-catalyst effect on UOR activity and helps to better design nickel-based UOR catalysts.

Li metal has emerged as a promising anode material for high energy density batteries, due to its low electrochemical potential and high specific capacity of 3860 mAh·g⁻¹. These characteristics make it an attractive choice for electric vehicles and power grids. However, Li-metal batteries are plagued by dendrite issues stemming from the high reactivity of Li metal, which can ultimately result in battery failure or even safety concerns. To overcome this challenge, various strategies have been proposed to prevent dendrite formation and enhance the safety of Li-metal batteries. This review critically examines the recent progress in the development of dendrite-free Li-metal batteries, with a particular emphasis on advanced approaches of 3D Li metal host construction. Our goal is to provide a comprehensive overview of the 3D hosts for suppressing Li dendrites and to offer guidance for the future development of superior Li metal batteries.

As one of the key components of solid-contact ion-selective electrodes (SC-ISEs), the SC layer plays a crucial role in electrode performance. Carbon materials, known for their efficient ion–electron signal conversion, chemical stability, and low cost, are considered ideal materials for solid-state transducing layers. In this review, the application of different types of carbon materials in SC-ISEs (from 2007 to 2023) has been comprehensively summarized and discussed. Representative carbon-based materials for the fabrication of SC-ISEs have been systematically outlined, and the influence of the structural characteristics of carbon materials on achieving excellent performance has been emphasized. Finally, the persistent challenges and potential opportunities are also highlighted and discussed, aiming to inspire the design and fabrication of next-generation SC-ISEs with multifunctional composite carbon materials in the future.

Supercapacitors (SCs) offer broad possibilities in the rising domain of military and civilian owing to their intrinsic properties of superior power density, long lifetime, and safety features. Despite of low‐cost, facile manufacture, and time‐saving, 3D printing technology unleashes the potential of SCs in terms of achieving desirable capacitance with high mass loading, fabrication of well‐designed complicated structures, and direct construction of on‐chip integration systems. In this review, first, the representative printing technologies for SCs and advanced printable materials are scrutinized for SCs and advanced printable materials. Then the structure design principles of electrodes and devices are respectively highlighted and reported cases are systematically summarized. Next, configurations of the SCs and their applications in various areas are described in detail. Finally, the promising research directions for the future are discussed. The perspectives reviewed here are expected to provide a comprehensive understanding of 3D‐printed SCs and guidance in realizing their promise in various applications.