Abstract:
Titanium and its alloys are extensively used in aerospace, marine engineering, and various technical industries owing 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 rely on 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 promising alternative for its unique advantages. This technique substantially reduces energy consumption and pollution emissions as well as simplifies equipment design and operational complexity. Among the various electrolytes explored, ionic liquids (ILs) have emerged as a pivotal component due to their wide electrochemical windows, low melting points, and high stability. Despite significant advancements, critical challenges such as low current efficiency and insufficient product purity remain unresolved. Furthermore, comprehensive reviews focusing specifically on near-room-temperature electrodeposition of titanium and its alloys in IL-based systems are still lacking. Therefore, this article systematically reviews the development of near-room-temperature electrodeposition methods for titanium and its alloys in aqueous solutions, organic solvents, and ILs. Key technical challenges are analyzed, including the complex speciation of titanium in IL media, the intricate process of titanium ion electroreduction, and difficulties in achieving deep reduction and high current efficiency. The article analyzes the causes and manifestations of defects in electrodeposited products in terms of composition and morphology. In addition, this article comprehensively summarizes the recent innovative optimization strategies and explores the use of multi-scale theoretical analysis combined with multi-dimensional in-situ experimental characterization to elucidate the mechanism of electrodeposition. Furthermore, 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, are discussed. 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 the electrodeposition of titanium and its alloys in near-room-temperature ILs. It aims to provide valuable guidance for fundamental research, offer theoretical support for technological breakthroughs, and facilitate the rapid development of large-scale industrial applications.