Progress in the precise structural regulation of single-walled carbon nanotubes and their applications in energy and electronics fields

Single-walled carbon nanotubes (SWCNTs) possess exceptional electronic, mechanical, and thermal properties, making them highly promising for applications in energy storage and conversion, electronics, and biomedical engineering. However, fully unlocking their potential relies heavily on precise control over their core structural characteristics—such as chirality, diameter, and surface chemistry—which are largely determined during synthesis. This review systematically summarizes recent advances in the precise structural regulation of SWCNTs and explores their applications in key fields, aiming to bridge the gap between laboratory research and industrial implementation.The structural control of SWCNTs focuses on four main aspects: catalyst design, dynamic optimization of growth conditions, the influence of substrates and carbon sources, and innovative preparation methods. In catalyst design, researchers have developed various advanced catalyst systems to tailor the chirality and diameter of SWCNTs. These include refractory metal nanoparticles and their carbides, which provide high structural stability and overcome limitations of traditional liquid catalysts; bimetallic systems that leverage synergistic effects to stabilize catalyst particle size and modulate electronic structure; and low-melting-point catalysts that interact with specific supports to enhance the adsorption and decomposition of carbon precursors.Dynamic optimization of growth conditions further refines structural control by tuning parameters such as temperature, carbon source partial pressure, and etchant concentration. These adjustments influence the nucleation kinetics and growth mechanisms of SWCNTs, enabling targeted regulation of diameter distribution and chirality selectivity. Substrates and carbon sources also play essential roles: substrate surface engineering—such as introducing defect sites or using atomically flat surfaces—guides the ordered growth and alignment of SWCNTs, while the choice of carbon source affects growth kinetics, thereby influencing the diameter and electronic properties of the nanotubes.Innovative synthesis methods have overcome limitations of conventional techniques. Examples include electric field-assisted plasma-enhanced chemical vapor deposition (PECVD) for selective growth of high-purity SWCNTs with defined electronic properties; machine learning approaches that accelerate the identification of optimal growth parameters by predicting structure–property relationships; and DNA origami-inspired spatial confinement techniques, which enable ultra-precise control over the spatial arrangement of SWCNTs.In terms of applications, SWCNTs demonstrate outstanding performance in energy and electronics due to their structural advantages. In energy storage, they enhance the performance of lithium-ion batteries by improving capacity retention and power density, boost the energy density and cycling stability of all-solid-state batteries, and reinforce the mechanical durability and energy storage capacity of flexible devices. In electronics, SWCNTs serve as key materials for high-performance field-effect transistors (FETs) with high on/off ratios, flexible transparent conductive films (TCFs) with excellent long-term stability, and highly sensitive strain sensors capable of detecting subtle biological motions.Despite these advances, the large-scale industrialization of SWCNTs faces challenges such as high synthesis costs, difficulties in achieving high purity, and poor dispersibility due to strong van der Waals interactions. Future efforts should focus on developing low-cost and sustainable catalysts, integrating artificial intelligence to optimize synthesis processes, and fostering interdisciplinary collaboration across nanotechnology, biomedicine, and information technology. Such initiatives will help transition SWCNTs from basic research to real-world industrial applications.