Speaker
Description
To address carbon dioxide emissions, battery performance must be improved. Lithium-ion batteries (LIBs) dominate the market, but their limited and geographically concentrated resources have prompted research into sodium-ion batteries (NIB) to replace LIBs [1]. At J-PARC, we employed positive muon spin relaxation ($\mu^+$SR) [2] and small-angle neutron scattering (SANS) [3] in hard carbon, which is a candidate for anodes in NIBs, to measure self-diffusion coefficients ($D^J$) and structural change, respectively. Our investigation of hard carbon revealed a sodium ion $D^J$ of $2.5\times10^{-11}$ cm$^2/s$—lower than lithium in graphite but with small activation energy. The operando cells have developed, and we compared diffusion in Li$_x$CoO$_2$ and Na$_x$CoO$_2$ systems under operando measurements, finding distinct concentration-dependent behaviors: lithium showed steep changes near $x$ = 1, while sodium decreased linearly with concentration [4,5]. In the presentation, we will also discuss the results of operando SNAS measurements on hard carbon.
[1] N. Yabuuchi et al., Chem. Rev. 114, 11636 (2014).
[2] K. Ohishi et al., ACS Phys. Chem. Au 2, 98, 107 (2021).
[3] K. Ohishi et al., J. Phys.: Conf. Ser. 2462, 0120048 (2023).
[4] K. Ohishi et al., ACS Appl. Energy Mater. 5, 12538-12544 (2022).
[5] K. Ohishi et al., ACS Appl. Energy Mater. 6, 8111-8119 (2023).
| k_ohishi@cross.or.jp | |
| Funding Agency | JST-GteX, JSPS KAKENHI |
| Did you request an Invitation Letter for a Visitors Visa Application | No |
