A novel ammonia and triethanolamine assisted sol-gel synthesis method was developed to fabricate TiO2 hollow spheres (THS). The hollow structure of TiO2 could be easily controlled by adjusting the amount of ammonia and triethanolamine. Photocatalytic activities of the THS were evaluated by the photodegradation of Rhodamine B (RhB). The results show that the anatase/rutile mixed-phase THS obtained from 850 °C thermal treatment exhibits higher photocatalytic activity than Degussa P25 (commercial TiO2 photocatalyst). In addition, electrochemical measurements demonstrate that the mixed-phase THS have potential applications in lithium-ion battery.