Coaxial nano-multilayered C/SnO2/TiO2 composites as anode materials for lithium-ion batteries

Tin dioxide (SnO₂) with a high theoretical specific capacity of 1494 mAh g^–1 is a promising candidate anode material for lithium storage. However, the shortcomings of serious volume expansion and low conductivity limit its wide application. Herein, coaxial nano-multilayered C/SnO₂/TiO₂ composites were fabricated via layer-by-layer self-assembly of TiO₂ and SnO₂-gel layers on the natural cellulose filter paper, followed by thermal treatment under a nitrogen atmosphere. Through engineering design of the assembly process, the optimal C/SnO₂/TiO₂ composite features five alternating SnO₂ and TiO₂ nanolayers, with TiO₂ as the outside shell (denoted as C/TSTST). This unique structure endows the C/TSTST with excellent structural stability and electrochemical kinetics, making it a high-performance anode for lithium-ion batteries (LIBs). The C/TSTST composite delivers a high reversible capacity of 676 mAh g⁻¹ at 0.1 A g⁻¹ after 200 cycles and retains a capacity of 504 mAh g⁻¹ at 1.0 A g⁻¹, which can be recovered to 781 mAh g⁻¹ at 0.1 A g⁻¹. The significantly enhanced electrochemical performance is attributed to the hierarchical hybrid structure, where the carbon core combined with coaxial TiO₂ nanolayers serves as a structural scaffold, ameliorating volume change of SnO₂ while creating abundant interfacial defects for enhanced lithium storage and rapid charge transport. These findings are further demonstrated by the density functional theory (DFT) calculations. This work provides an efficient strategy for designing coaxial nano-multilayered transition metal oxide-related electrode materials, offering new insights into high-performance LIBs anodes.

Graphical abstract