Researchers from the Samsung Advanced Institute of Technology report enhancing the energy density of manganese oxide (NaxMnO2) cathode materials for sodium rechargeable batteries by incorporating aluminum. A paper describing their discovery is published in the journal ChemSusChem.
|Han et al. Click to enlarge.|
Although there is growing interest in Na-ion batteries (NIBs) as an alternative to Li-ion batteries (LIBs), NIB overall electrochemical performance remains inferior to Li chemistry. (Earlier post.)
Incorporating aluminum results in NaAl0.1Mn0.9O2, which shows a much higher initial discharge capacity and superior cycling performance compared to pristine Na0.65MnO2.
The Samsung researchers attributed this enhancement to the formation of a new orthorhombic layered NaMnO2 phase merged with a small amount of tunnel Na0.44MnO2 phase, and to improvements in the surface stability of the NaAl0.1Mn0.9O2 particles.
Our findings regarding the phase transformation and structure stabilization induced by incorporation of aluminum, closely related to the structural analogy between orthorhombic Na0.44MnO2 and NaAl0.1Mn0.9O2, suggest a strategy for achieving sodium rechargeable batteries with high energy density and stability.—Han et al.
Han, D.-W., Ku, J.-H., Kim, R.-H., Yun, D.-J., Lee, S.-S. and Doo, S.-G. (2014) “Aluminum Manganese Oxides with Mixed Crystal Structure: High-Energy-Density Cathodes for Rechargeable Sodium Batteries,” ChemSusChem doi: 10.1002/cssc.201301254