Submicron-sized mesoporous anatase TiO2 beads with trapped SnO2 for long-term, high-rate lithium storage

Submicron-sized mesoporous anatase TiO2 beads with trapped SnO2 (TS beads) have been fabricated by using mesoporous anatase TiO2 beads as precursors prepared by a combined sol-gel and solvothermal method. The scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, transmission electron microscopy (TEM), X-ray powder diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) elemental mapping, and X-ray photoelectron spectroscopy (XPS) are used to confirm that the SnO2 is successfully trapped by mesoporous anatase TiO2 beads. The electrochemical performance of TiO2 beads for lithium storage is significantly improved by trapping SnO2. The TS beads with 24.12% SnO2 trapping ratio show a discharge capacity of 436.5 mA h g−1 after 850 cycles at 1 C (1 C = 170 mA g−1) charge-discharge rate. Moreover, the TS beads also exhibit 225.7 mA h g−1 and 119.7 mA h g−1 discharge capacities at 5 C and 10 C charge-discharge rates after 2000 cycles, respectively. In addition, the Coulombic efficiency is nearly 100% at each cycle at various charge-discharge rates. The excellent lithium storage properties of TS beads could be attributed to their synergistic effect that SnO2 provides high lithium storage capacity and mesoporous TiO2 accommodates volume change of SnO2 effectively.