Three-Dimensional Bi₂S₃ Nanoflowers with Built-In MXene Nanosheets for Reversible Lithium-Ion Storage with Enhanced Performance and Kinetics

Bismuth sulfide (Bi2S3) has been considered as a potential anode candidate for high-energy lithium-ion batteries (LIBs) due to its high theoretical Li-ion storage capacity. However, the Bi2S3 anode suffers from rapid capacity fading under prolonged electrochemical cycling, owing to reaction strain and drastic volume expansion during the charge/discharge processes. Herein, we report an MXene-integrated structure design for the Bi2S3 nanoflowers through an in situ hydrothermal method, resulting in titanium carbide (Ti3C2)-supported Bi2S3 nanoflowers (Bi2S3@Ti3C2) with proper structural integrity via chemical interaction between two components. The Bi2S3@Ti3C2 nanocomposite anode significantly outperformed the pristine Bi2S3 nanoflowers in terms of lithium storage performance, retaining a capacity of approximately 335 mAh g–1 at 200 mA g–1 and 301 mAh g–1 at a higher current density of 1000 mA g–1 over 100 cycles. Moreover, the composite material Bi2S3@Ti3C2 also delivers a cycling performance of 181.3 mAh g–1 over 400 cycles with a high mass loading. Enhanced lithium storage kinetics of the composite Bi2S3@Ti3C2 has also been demonstrated by the galvanostatic intermittent titration technique and in situ electrochemical impedance spectroscopic measurements. This work provides structural engineering for ameliorating transition metal chalcogenides as high-capacity anode materials for LIBs with better rate capability and cycling stability.