Leaf-inspired design of mesoporous Sb 2 S 3 /N-doped Ti 3 C 2 T x composite towards fast sodium storage

Owing to excellent conductivity and abundant surface terminals, MXene-based heterostructures have been intensively investigated as energy storage materials. However, elaborate design of the structure and composition of MXene-based hybrids towards superior electrochemical performance is still challenging. Herein, we present an ingenious leaf-inspired design for preparing a unique Sb2S3/nitrogen-doped Ti3C2Tx MXene (L-Sb2S3/Ti3C2) hybrid. In-situ TEM observations reveal that the leaflike Sb2S3 nanoparticles with numerous mesopores can well relieve the large volume changes via an inward pore filling mechanism with only 20% outward expansion, whereas highly conductive N-doped Ti3C2Tx nanosheets can serve as the robust mechanical support to reinforce the structural integrity of the hybrid. Benefiting from the structural and constituent merits, the L-Sb2S3/Ti3C2 anode fabricated exhibits a fast sodium storage behavior in terms of outstanding rate capability (339.5 mA h g−1 at 2,000 mA g−1) and high reversible capacity at high current density (358.2 mA h g−1 at 1,000 mA g−1 after 100 cycles). Electrochemical kinetic tests and theoretical simulation further manifest that the boosted electrochemical performance mainly arises from such a unique leaf-like Sb2S3 mesoporous nanostructure with abundant active sites, and enhanced Na+ adsorption energy on the heterojunction formed between Sb2S3 nanoparticles and Ti3C2 matrix.