Synthesis of starfish-like Cu2O nanocrystals through γ-irradiation and their application in lithium-ion batteries

In this study, single-crystalline starfish-like cuprous oxide (Cu2O) nanocrystals with the backbones lengths in the range of 660 nm∼16 μm are successfully prepared through γ-irradiation, the cetyltrimethylammonium bromide (CTAB) is used as a capping material or soft colloidal templates. Without the addition of CTAB in the reaction system, irregular Cu2O nanoclusters were obtained and their diameter is about 200 nm∼1 μm. Controlling the concentration ratio of CTAB to the copper ions, starfish-like morphology of Cu2O can be obtained in high yield. Their structures are characterized by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. The possible growth mechanism of the starfish structure is discussed in the text. For potential application in lithium-ion batteries, an electrode made of the starfish-like Cu2O shows excellent electrochemical cycling performance and high-rate capability. Compared with the Cu2O nanoclusters, the starfish-like Cu2O exhibits an improved electrochemical cycling stability. The capacity of the starfish-like Cu2O can maintain 340 and 215 mAh g−1 after 50 cycles at the rate of 0.1 C and 5 C, respectively. The reversible capacity holds 60% as the discharge–charge rate even increases by 50 times.