High-performance Bi₂Se₃/MXene/SWCNT heterostructures as binder-free anodes in lithium-ion batteries

Bi2Se3, MXenes, and SWCNTs are promising potential alternatives to replace the conventional graphite in the anodes of lithium-ion batteries (LIBs) and enhance their performance. However, all these materials have drawbacks, such as large volume expansion and Se dissolution (Bi2Se3), large irreversible capacity (SWCNTs), and poor specific capacity (MXenes). In this work, a combination of nanostructured Bi2Se3 and MXenes with SWCNTs in Bi2Se3/MXene/SWCNT heterostructures is used as a novel architecture for binder-free anode material in non-aqueous LIBs. Bi2Se3/MXene/SWCNT heterostructures with different Bi2Se3 : MXene : SWCNT mass ratios were fabricated by direct physical vapour deposition of Bi2Se3 nanostructures onto MXene/SWCNT networks. Bi2Se3/MXene/SWCNT heterostructures showed improved electrochemical performance in comparison with the individual components of the heterostructures. This enhancement can be attributed to the high electrode/electrolyte contact area provided by the nanostructured materials, leading to a substantial capacitive contribution to charge storage. In addition, the formation of Se-C bonds on SWCNT surfaces prevented the dissolution of Se. The best performance was shown by Bi2Se3/MXene/SWCNT heterostructures with the mass ratio of 1 : 1 : 2, which reached capacity of 738 mA h g(-1) at 0.1 A g(-1) after 100 cycles. Moreover, after 900 cycles at 10.0 A g(-1) current density, these heterostructures retained an excellent capacity of 320 mA h g(-1). This performance indicates significant potential for Bi2Se3/MXenes/SWCNTs heterostructures as binder-free anodes for high-rate-performance lithium-ion batteries.