Highly conductive sodium solid electrolyte exhibiting electrochemical stability
Researchers from Toyohashi University of Technology have made a significant breakthrough in the development of all-solid-state sodium (Na) ion batteries. Led by Noritaka Mizuno, the team has developed a Cl-substituted NaSbS solid electrolyte that promises to improve the stability and ionic conductivity of these batteries.
The study, titled 'Effects of Substituting S with Cl on the Structural and Electrochemical Characteristics of NaSbS Solid Electrolytes', was published in the journal ACS Applied Energy Materials in 2018. The research team discovered that heavy Cl doping is effective in improving the stability with the Na metal anode, and this improvement was confirmed through various tests.
One of the key findings of the study is that the ionic conductivity of the Cl-substituted NaSbS solid electrolyte improved by up to three times compared to the sample without a Cl substitution. This improvement is attributed to the formation of a crystal structure with a three-dimensional ion diffusion pathway, which allows Na ions to move easier in three dimensions.
The Cl-substituted NaSbS solid electrolyte has a framework that facilitates the movement of Na ions, leading to superior stability with Na metal anodes compared to the sample without a Cl substitution. Among various Na solid electrolytes, NaSbS solid electrolytes have a high conductivity of 1 mS cm-1 or higher at room temperature and are widely researched. However, achieving high ion conductivity through a simpler synthetic process has been notably problematic.
The research team, consisting of Hirotada Gamo, Nguyen Huu Huy Phuc, Hiroyuki Muto, and Atsunori Matsuda, believes that their findings could potentially be combined with liquid-phase coating technology to achieve a high storage capacity and stable cycling for all-solid-state Na-ion batteries. This could be a significant step forward in the development of these batteries, which are gaining attention due to their potential for large-scale energy storage using low-cost and abundantly available Na resources.
In conclusion, the study by Mizuno and his team has uncovered an important design principle for developing an ideal solid electrolyte with high ionic conductivity and superior electrochemical stability. The Cl-substituted NaSbS solid electrolyte is a promising development in the field of all-solid-state Na-ion batteries and could play a significant role in the future of energy storage technology.
