One-pot synthesis of uniform Cu2O–CuO–TiO2 hollow nanocages with highly stable lithium storage properties†
Unique Cu2O–CuO–TiO2 hollow nanocages are synthesized by a facile self-template hydrothermal method without any surfactants and additional templates. In the synthesis process, Cu2O serves as the self-template to induce the morphology control of hollow nanocages. As the precursor to fabricate the TiO2 layer, TiF4 also etches the Cu2O template to form a hollow structure by releasing HF during the hydrothermal treatment. The design of combining copper oxides with the TiO2 layer in a hollow nanocage structure is favorable for Li-ion batteries (LIBs). Because it is beneficial to fully utilize the respective advantages of different components and solve the critical volume expansion issue that exists in almost every metal oxide electrode. As anode materials of LIBs, the as-prepared hollow nanocages of ternary metal oxides exhibit a superior reversible capacity of 700 mA h g−1 at 50 mA g−1 for over 85 cycles, which is much higher than the theoretical capacity of the compounds and any of their compositions. The capacity of the anode materials still deliver a negligible decay when restart charging/discharging after stopped more than one month. The outstanding electrochemical performance can be attributed to the synergetic effects of individual components and the special structure, namely, higher theoretical capacity of copper oxides, the well-designed hollow structure, and good structural stability and cycling stability of TiO2.