| 研究実績の概要 |
Our research, in collaboration with the Yamada-Kitada Lab, focuses on optimizing high-voltage cathode materials for sodium-ion batteries (SIBs) through advanced surface and interface modifications. SIBs offer cost advantages over lithium-ion batteries due to cheaper raw materials, despite their lower energy density (-2.71V Na+/Na vs -3.04V Li+/Li).
We have targeted Alluaudite Na2+2xFe2-x(SO4)3 (NFS) and NASICON Na3Cr2(PO4)3 (NCP) as potential high-performance cathodes. Both materials offer operational voltages of 3.8V and 4.6V, respectively, and are cost-effective, achieving energy densities comparable to current commercial cathodes (400-500Wh/kg). However, NFS suffers from hygroscopicity, and NCP from in-situ electrochemical particle dissolution, impacting structural stability and performance.
Efforts to address these critical issues and enhance the viability and stability of these cathode materials have resulted in the following research achievements to date:
(1) Developed a novel solution-based synthesis for high-purity NFS. (2) Introduced a silane-based surface coating for NFS to reduce hygroscopicity. (3) Conducted comprehensive characterizations via XRD, SEM, FTIR, and Raman Spectroscopy. (4) Investigated the effects of K-ion substitution on NCP’s crystal structure. (5) Discovered new layered Na-K chromium phosphate phase, Na3-xKxCr3(PO4)4 (monoclinic, C2/c) via XRD. (6) DFT modelling of electronic structure for both NFS and NCP.
|
