Nguyen Thang Phan, Kim Il Tae
Department of Chemical and Biological Engineering, Gachon University, Seongnam-si 13120, Gyeonggi-do, Republic of Korea.
Micromachines (Basel). 2023 Feb 23;14(3):521. doi: 10.3390/mi14030521.
Sodium-ion batteries (SIBs) are potential replacements for lithium-ion batteries owing to their comparable energy density and the abundance of sodium. However, the low potential and low stability of their cathode materials have prevented their commercialization. Prussian blue analogs are ideal cathode materials for SIBs owing to the numerous diffusion channels in their 3D structure and their high potential vs. Na/Na. In this study, we fabricated various Fe-V-incorporated hexacyanoferrates, which are Prussian blue analogs, via a one-step synthesis. These compounds changed their colors from blue to green to yellow with increasing amounts of incorporated V ions. The X-ray photoelectron spectroscopy spectrum revealed that V was oxidized to V in the cubic Prussian blue structure, which enhanced the electrochemical stability and increased the voltage platform. The vanadium ferrocyanide Prussian blue (VFPB1) electrode, which contains V and Fe in the Prussian blue structure, showed Na insertion/extraction potential of 3.26/3.65 V vs. Na/Na. The cycling test revealed a stable capacity of ~70 mAh g at a rate of 50 mA g and a capacity retention of 82.5% after 100 cycles. We believe that this Fe-V-incorporated Prussian green cathode material is a promising candidate for stable and high-voltage cathodes for SIBs.
钠离子电池（SIBs）因其可比的能量密度和钠的丰富储量而成为锂离子电池的潜在替代品。然而，其阴极材料的低电位和低稳定性阻碍了它们的商业化。普鲁士蓝类似物由于其三维结构中众多的扩散通道以及相对于Na/Na+的高电位，是钠离子电池理想的阴极材料。在本研究中，我们通过一步合成法制备了各种掺入铁和钒的六氰合铁酸盐，它们是普鲁士蓝类似物。随着掺入钒离子量的增加，这些化合物的颜色从蓝色变为绿色再变为黄色。X射线光电子能谱表明，在立方普鲁士蓝结构中钒被氧化为V5+，这增强了电化学稳定性并提高了电压平台。在普鲁士蓝结构中含有V5+和Fe3+的亚铁氰化钒普鲁士蓝（VFPB1）电极，相对于Na/Na+显示出3.26/3.65 V的钠嵌入/脱出电位。循环测试表明，在50 mA g-1的电流密度下，其容量稳定在~70 mAh g-1左右，100次循环后容量保持率为82.5%。我们认为这种掺入铁和钒元素的普鲁士绿阴极材料是钠离子电池稳定且高电压阴极的有前途的候选材料。
