Template-free construction of hollow TiO2 microspheres for long-life and high-capacity lithium storage

Highlights: • Hollow TiO₂ microspheres with abundant mesoporous were constructed by a simple and template-free method. • The unique hollow spherical structures are beneficial to accelerate lithium ion diffusion and buffer the volume expansion. • Such satisfying long-term cycling performances at large current densities for lithium storage can be obtained. -- Abstract: Hollow spherical structures with abundant mesoporous are of great interest for electrode materials in lithium-ion batteries (LIBs). Although there are many synthetic strategies, using template-free methods to construct the hollow spherical structures still faces great challenges. Herein, we designed a simple template-free method to successfully obtain uniform hollow TiO₂ microspheres (TiO₂–H) with a well-defined hollow interior and abundant mesoporous. Owing to the structural superiority, the as-prepared TiO₂–H as an electrode material for LIBs delivers a high specific capacity of ∼132 mAh g⁻¹ at a current density of 2.0 C after 200 cycles. Besides, it also exhibits satisfying long-term cycling performances with a high specific capacity of ∼100 mAh g⁻¹ at a large current density of 5.0 C after 800 cycles. These superior cycling performances and strong structure stability of TiO₂–H electrodes are attributed to the hollow spherical structures with large specific surface areas and rich mesoporous, which can ensure Li ion diffusion and provide sufficient electrochemical reaction sites, as well as remit the large volume changes.