锂/钠混合离子电池正极材料Na2FePO4F/C的第一性原理研究

将锂/钠混合离子电池正极材料Na₂FePO₄F/C作为研究对象，建立Na₂FePO₄F、NaFePO₄F、NaLiFePO₄F、Na₂FePO₄F/C、NaFePO₄F/C、NaLiFePO₄F/C的结构模型，并依据第一性原理密度泛函理论，分析了这六种材料的能带、态密度、键长变化以及形成能.研究结果显示，相比于单一的Na₂FePO₄F,石墨烯包覆的Na₂FePO₄F的金属特性更良好，电子传输性质更优异，同时具有更加稳定的结构，这表明在电池长时间循环过程中，Na₂FePO₄F/C晶体结构不容易发生坍塌，容量衰减率更小，这为碳包覆改性制备复合正极材料提供了理论依据.

First-principles research on cathode material Na2FePO4F/C for lithium/sodium hybrid ion battery

Na2FePO4F/C, lithium/sodium hybrid ion battery cathode material, was taken to work as the research object, and the structure models of Na2FePO4F, NaFePO4F, NaLiFePO4F, Na2FePO4F/C, NaFePO4F/C, NaLiFePO4F/C were established, whose energy band, density of state, bond length change and formation energy were analyzed based on the first-principles density functional theory. It was found that, compared with a bare Na2FePO4F, the graphene-coated Na2FePO4F has better metal properties, better electron transport properties, and a more stable structure, which indicates that the Na2FePO4F/C crystal structure is not prone to collapse during the long-term battery cycle, and the capacity decay rate is smaller. This provides a theoretical basis for the preparation of composite cathode materials by carbon coating modification.