Chen Tongtong, Han Xianying, Jie Mengling, Guo Zhiwu, Li Jiangang, He Xiangming
College of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617, China.
Beijing Key Laboratory of Fuels Cleaning and Advanced Catalytic Emission Reduction Technology, Beijing 102617, China.
Materials (Basel). 2024 Jun 1;17(11):2679. doi: 10.3390/ma17112679.
NaFe(PO)PO/C (NFPP) is a promising cathode material for sodium-ion batteries, but its electrochemical performance is heavily impeded by its low electronic conductivity. To address this, pure-phase Mo-doped NaFeMo(PO)PO/C (Mox-NFPP, x = 0, 0.05, 0.10, 0.15) with the Pn21a space group is successfully synthesized through spray drying and annealing methods. Density functional theory (DFT) calculations reveal that Mo doping facilitates the transition of electrons from the valence to the conduction band, thus enhancing the intrinsic electron conductivity of Mox-NFPP. With an optimal Mo doping level of x = 0.10, Mo0.10-NFPP exhibits lower charge transfer resistance, higher sodium-ion diffusion coefficients, and superior rate performance. As a result, the Mo0.10-NFPP cathode offers an initial discharge capacity of up to 123.9 mAh g at 0.1 C, nearly reaching its theoretical capacity. Even at a high rate of 10 C, it delivers a high discharge capacity of 86.09 mAh g, maintaining 96.18% of its capacity after 500 cycles. This research presents a new and straightforward strategy to enhance the electrochemical performance of NFPP cathode materials for sodium-ion batteries.
NaFe(PO)PO/C（NFPP）是一种很有前景的钠离子电池正极材料，但其电化学性能因电子电导率低而受到严重阻碍。为了解决这一问题，通过喷雾干燥和退火方法成功合成了具有Pn21a空间群的纯相Mo掺杂NaFeMo(PO)PO/C（Mox-NFPP，x = 0、0.05、0.10、0.15）。密度泛函理论（DFT）计算表明，Mo掺杂促进了电子从价带向导带的跃迁，从而提高了Mox-NFPP的本征电子电导率。在最佳Mo掺杂水平x = 0.10时，Mo0.10-NFPP表现出更低的电荷转移电阻、更高的钠离子扩散系数和优异的倍率性能。因此，Mo0.10-NFPP正极在0.1 C时的初始放电容量高达123.9 mAh g，几乎达到其理论容量。即使在10 C的高倍率下，它也能提供86.09 mAh g的高放电容量，在500次循环后保持其容量的96.18%。本研究提出了一种新颖且直接的策略来提高钠离子电池NFPP正极材料的电化学性能。
