Computational studies of olivine NaMPO4 (M: Mn, Fe, Co)
Presented by Mr. Ndanduleni Lesley LETHOLE on 8 Jul 2014 from 17:10 to 19:00
Type: Poster Presentation
Track: Track A - Division for Physics of Condensed Matter and Materials
Board #: A.113
Efforts to deal with environmental pollution and exhaustion of oil resources have been the centre of attention throughout the research industry. Hybrid electric vehicles powered by the lithium ion battery have been developed. However, the scarcity of lithium and the possibility of using much safer aqueous electrolytes in sodium ion batteries have shifted interest on sodium ion batteries to ensure sustainability and optimal safety. However, the major drawback for the sodium materials has been their low charge/discharge capacities. Previous studies have shown that NaFePO<sub>4</sub> and NaCoPO<sub>4</sub> offer charge/discharge capacities of 12 mAh/g and 2.0 mAh/g, respectively, which is very less compare to LiFePO<sub>4</sub> (170 mAh/g), LiMnPO<sub>4</sub> (70 mAh/g) and LiCoPO<sub>4</sub> (70 mAh/g). In this study, we investigate the structural, thermodynamic, electronic and mechanical properties of the olivine NaMPO<sub>4</sub> to determine their capabilities as future cathode materials for sodium ion batteries. Calculations have been performed within DFT+U method as implemented in the Vienna Ab initio Simulation Package code. The calculated cell parameters for NaFePO<sub>4</sub> and NaCoPO<sub>4</sub> were found to be in good agreement to the experimental to within 3%. The heats of formation suggested that NaMnPO<sub>4</sub> is the most stable olivine structure, due to the lowest formation energy (-1292 kJ/mol).
NGOEPE P.E.; firstname.lastname@example.org; UNIVERSITY OF LIMPOPO