For realization of low carbon society, the popularization of electric vehicles and plug-in hybrid vehicles by using high performances secondary batteries is important. Many researchers have studied Li-ion batteries with high energy density and high power density for automotive batteries. Especially, fabrication of nano-materials and development of process for nanostructural control have attracted researchers in industrial and academic fields because the short diffusion length of lithium ions in nanomaterials and high surface area of nanomaterials are suitable for high power density.

We have studied many kinds of nanostructural control processes of active materials for electrodes. In these days, we focus the crystalinity of the materials and easy fabrication processes. We reported fabrication of single crystalline nanowires of LiMn_xFe_1-xPO₄ and mesocrystal nanowires constructed by oriented LiMn_0.4Fe_0.6PO₄ grains by electrospinning methods.^1-3 Moreover, we have studied Na-ion batteries, which are expected as low cost secondary batteries because sodium is abundant element.

Here, we report the fabrication of mesocrystal nanowires constructed by Na₃V₂(PO₄)₃ oriented nanoparticles by electrospinning method and the battery-performances as Na-ion batteries.⁴ In addition, we report the soft X-ray adsorption spectroscopy of the materials for understanding about the mechanism of Na insertion/extraction

 

References

[1] K. Kagesawa, E. Hosono, et al., CrystEngComm, 2013, 15, 6638.

[2] K. Kagesawa, E. Hosono, et al., J. Power Sources, 2014, 248, 615.

[3] J. Kikkawa, E. Hosono, et al., J. Phys. Chem. C, 2014, 118, 7678.

[4] S. Kajiyama, E. Hosono, et al., Chem. Eur. J.2014, 20, 12636.