SnO<sub>2</sub> Quantum Dots Interspersed d-Ti<sub>3</sub>C<sub>2</sub>Tx MXene Heterostructure with Enhanced Performance for Lithium Ion Battery
Libo Wang, Yan He, Darong Liu, Lu Liu, Hao Chen, Qianku Hu, Xuqing Liu, Aiguo Zhou
Abstract
Ti 3 C 2 T x 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 SnO 2 QDs@delaminated Ti 3 C 2 T x (d-Ti 3 C 2 T x ) heterostructure composite that is produced via in situ growth of SnO 2 QDs on the layer of d-Ti 3 C 2 T x nanosheets and uses a facile ultrasound irradiation method. Results illustrate that SnO 2 QDs are uniformly anchored on the surface of d-Ti 3 C 2 T x layer. The d-Ti 3 C 2 T x nanosheets inhibits the agglomeration of SnO 2 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-Ti 3 C 2 T x and SnO 2 QDs, SnO 2 QDs@d-Ti 3 C 2 T x nanocomposites greatly improve the reversible capacity. Remarkably, the SnO 2 @d-Ti 3 C 2 T x 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 SnO 2 QDs on MXene prevents the re-stacking of d-Ti 3 C 2 T x layers and increases the Li + storage; thus, this system exhibits excellent electrochemical properties for LIBs.