Ab Initio Study on Structural Properties of NaFeSO4OH Cathode Material for Rechargeable Sodium Ion Battery

Layered lithium iron hydroxysulfate, LiFeSO 4 OH was recently proposed as a cathode material for lithium ion batteries (LIBs) made up of low cost and sustainable components. Here, we report ab-initio investigation into the structural properties of its sodium analogue, NaFeSO 4 OH obtained from in-situ substitution of lithium (Li) with sodium (Na). A robust host structure for NaFeSO 4 OH was discovered owing to strong Fe-O and S-O bonds, a good indicator for thermal stability and long cycle life. The Na ions are strongly held by the oxygen atoms, but the charge density map proves that the bond between the two is still ionic.