Abstract:
Titanium and its alloys are extensively utilized in aerospace, marine engineering, and various technical industries due to their exceptional specific strength and superior corrosion resistance. Traditional methods of titanium production primarily fall into two categories: metallothermic reduction and molten salt electrolysis. However, both approaches require high-temperature conditions and face systemic challenges, such as stringent material requirements, high energy consumption, and substantial pollutant emissions. These issues pose significant obstacles to the transition of titanium metallurgy toward low-carbon and energy-efficient paradigms. In this context, near-room-temperature electrodeposition has garnered increasing attention as a focus of research for its unique advantages. This technique not only substantially reduces energy consumption and pollution emissions but also simplifies equipment design and operational complexity. Owing to their wide electrochemical windows, low melting points, and high stability, ionic liquids (ILs) have emerged as a pivotal component of this system, attracting considerable research attention. Despite significant advancements in related research in recent years, critical challenges such as low current efficiency and insufficient product purity remain unresolved. Furthermore, there is a notable lack of comprehensive review articles specifically addressing the electrodeposition of titanium and its alloys using ILs at near-room-temperature, particularly those offering systematic analyses of technical challenges and potential optimization pathways. Therefore, in order to further summarize the achievements in related fields, this article first systematically reviews the development of electrodeposition methods for titanium and its alloys in near-room-temperature systems, covering aqueous solutions, organic solvents, and ionic liquids (ILs). Then it focuses on analyzing the key challenges faced by near-room-temperature IL-based systems. First, the complexity of the electrodeposition mechanism is analyzed from two aspects: the complex speciation of titanium in the ionic liquid media and the intricate process of titanium ion electroreduction. Second, the difficulties in achieving deep reduction of titanium ions and achieving high current efficiency are discussed, highlighting the challenges in electrodepositing pure titanium and its alloys. Finally, the article analyzes the causes and manifestations of defects in electrodeposited products in terms of composition and morphology. In addition, this article further comprehensively summarizes the innovative optimization strategies for near-room-temperature ILs electrodeposition of titanium and its alloys, and explores the use of multi-scale theoretical analysis combined with multi-dimensional in-situ experimental characterization to elucidate the electrodeposition mechanism. The paper further outlines strategies for efficient electrodeposition of titanium and its alloys, including the design and development of novel ILs with excellent performance, analysis of electrode processes, and the implementation of corresponding optimization measures, aimed at enabling the deep reduction of titanium ions for electrodeposition of pure titanium and improving current efficiency. An innovative control strategy for electrodeposition products based on multi-parameter and cross-spatiotemporal coupling regulation is also proposed. On this basis, the importance of establishing machine learning models to enable real-time prediction and control is also emphasized. Finally, this article looks forward to the future development challenges and potential opportunities in near-room-temperature ILs electrodeposition of titanium and its alloys. It aims to provide valuable references for fundamental research, to offer theoretical support for technological breakthroughs, and to facilitate the rapid development of large-scale industrial applications.