SnO2 Quantum Dots Interspersed d-Ti3C2Tx MXene Heterostructure with Enhanced Performance for Lithium Ion Battery

Abstract

Ti3C2Tx MXene is an important concern for lithium ion batteries (LIB) because of its two-dimensional (2D) open structure, excellent electrical conductivity, and low Li+ diffusion barrier. However, MXene anodes have a lower capacity, which limits their further application in LIBs. This study presents a SnO2 QDs@delaminated Ti3C2Tx (d-Ti3C2Tx) heterostructure composite that is produced via in situ growth of SnO2 QDs on the layer of d-Ti3C2Tx nanosheets and uses a facile ultrasound irradiation method. Results illustrate that SnO2 QDs are uniformly anchored on the surface of d-Ti3C2Tx layer. The d-Ti3C2Tx nanosheets inhibits the agglomeration of SnO2 QD nanoparticles and volume expansion during the charging-discharging process. The hierarchical structure can enlarge the interface area of electrode and electrolyte, which accelerating Li-ion and electron diffusion and transition processes. Electrochemical results reveal that compared to pure d-Ti3C2Tx and SnO2 QDs, SnO2 QDs@d-Ti3C2Tx nanocomposites greatly improve the reversible capacity. Remarkably, the SnO2@d-Ti3C2Tx composite maintains 390 mAh·g−1 with a capacity recovery after 100 cycles at current density of 1000 mA·g−1. The synergistic effect of SnO2 QDs on MXene prevents the re-stacking of d-Ti3C2Tx layers and increases the Li+ storage; thus, this system exhibits excellent electrochemical properties for LIBs.