关键词: 纳米纤维硒, 反向溶剂法, 硒正极, 锂二次电池

Abstract:

Nano-fibrous selenium of high purity and crystallinity with a diameter of 100 nm were synthesized by the reverse solvent method. The structure and morphology of products were characterized by X-ray diffraction and scanning electron microscope, respectively. Since the size of elemental selenium is reduced, the inactivaton effect induced by the coverage of fully insulated discharge product Li₂Se on Se particles surface is mitigated, thus greatly improving the utilization coefficient of active materials and alleviating the capacity fading of lithium-selenium batteries. Compared with the pristine selenium cathode, Se fiber electrode presents higher specific capacity and better cycling stability which delivers an initial specific discharge capacity of 465 mAh/g at 0.1C (1C=675 mAh/g) and maintains a capacity of 213 mAh/g after 40 cycles. Meanwhile, Se fiber electrode shows higher electrochemical activity than pristine Se electrode due to its shorter lithium ion diffusion path, resulting in a substantially enhanced rate capability of Se fiber electrode.

Key words: nano-fibrous selenium, reverse solvent method, selenium cathode, secondary lithium battery