Low-temperature synthesis of CeB6 nanowires and nanoparticles as feasible lithium-ion anode materials

摘要

Metallic CeB6 nanomaterials were prepared via the low-temperature solution combustion method (nanoparticles) and high-pressure solid state reaction (nanowires). X-ray diffraction patterns and High-resolution transmission electron microscopy images reveal that CeB6 nanoparticles are highly crystalline and CeB6 nanowires are single crystals. The X-ray photoelectron spectroscopy analysis indicates that the cerium is present in the +3 and +4 mixed-valence state in CeB6. As lithium-ion anodes, CeB6 nanowires (nanoparticles) electrode achieves a capacity of similar to 531 (338) mA h g(-1) in the initial cycle and keeps a reversible capacity of similar to 225 (185) mA h g(-1) after 60 cycles. CeB6 nanowires are tested for 6000 cycles at 1000 mA g(-1), which shows a specific capacity approaching to the capacity at 100 mA g(-1) in spite of fluctuation within a narrow range, and keep similar to 168 mA h g(-1) after 6000 cycles, indicating a stable cycling performance owing to the excellent metal-like conductivity of (similar to 5.67 x 10(3) S m(-1)). The reason of capacity rising is that the reduction and oxidation levels of CeB6 electrodes are improved after the 2nd cycle with Li+ insertion/extraction. Meanwhile, kinetic analysis reveals that the Li+ storage mechanism is mainly controlled by a surface capacitive behavior. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.