1. Chalcopyrite-Derived NaxMO2 (M = Cu, Fe, Mn) Cathode: Tuning Impurities for Self-Doping
- Author
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Yuehua Hu, Ji Xiaobo, Yue Yang, Hongshuai Hou, Feng Jiang, Yun Zhang, Xu Gao, Wei Sun, and Guoqiang Zou
- Subjects
Materials science ,Chalcopyrite ,Doping ,Sodium-ion battery ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Cathode ,Energy storage ,0104 chemical sciences ,law.invention ,Chemical engineering ,law ,Impurity ,Structural stability ,Phase (matter) ,visual_art ,visual_art.visual_art_medium ,General Materials Science ,0210 nano-technology - Abstract
Discovering cathode materials composed of earth-abundant elements has become the current priority for developing sodium-ion batteries (SIBs) to meet the ever-increasing demand of large-scale energy storage. Herein, for the first time, layered NaxMO2 (M = Cu, Fe, Mn) cathodes are successfully prepared by directly using concentrated chalcopyrite ores as precursors. Greatly, impurity elements like Si and Ca are found to be crucial to tailoring the phase structure of as-obtained layered oxides as a P2 or O3 type, which removes the traditional concern that the impurities may restrict the utilization of natural ores. More interestingly, a certain amount of the Ca elements remaining in the Na sites through a self-doping process endows the P2-type products with enhanced structural stability. In half-cells, P2-type NaxMO2 with self-doped Ca elements shows superior rate capability and cycling stability (56 mAh g-1 at 5 C and 90% capacity retention after 100 cycles at 1 C). In contrast, less impurity elements are favorable for O3-type oxides to achieve a high capacity of 107 mAh g-1 at 0.1 C and 84% capacity retention after 200 cycles at 2 C. This new strategy would efficiently shorten the process for preparing electrode materials and open a feasible route to construct cheap and durable SIBs.
- Published
- 2019