TY - CHAP
T1 - Many-Particle Na-Ion Dynamics in NaMPO4 Olivine Phosphates (M = Mn, Fe)
AU - Flack, T.
AU - Jobbins, S.A.
AU - Boulfelfel, S. E.
AU - Leoni, S.
PY - 2024/7/5
Y1 - 2024/7/5
N2 - NaMPO
4 (M = Mn, Fe) olivine phosphates represent less expensive, safer and sustainable alternatives to Lithium-ion materials for battery applications. Compared to their lithium analogues, NaMPO
4 materials exist in two structures, maricite and olivine. Their implementation calls for an in-depth investigation of diffusion/conduction mechanisms, including conductivity dimensionality and how structural features map onto Na pathways. In this work, we present a refined version of our finite temperature molecular dynamics “shooting” approach, originally designed to enhance Li hopping probability in lithiated olivine compounds. We perform a comparative analysis of ion mobility in both Mn and Fe olivine materials, focused on many-particle effects. Therein, we identify main [010] diffusion channels, as well as means of inter-channel couplings, in the form of Na cross-channel [001] hopping, which markedly impact the overall mobility efficiency as measured by self-diffusion coefficients. Through introduction of antisite defects, additional pathways along [100] appear, which are specific for Na olivine phosphates, indicating limited transferability of observations made on the Li compounds, both qualitatively and quantitatively. The overall diffusion figures of merit result from the competition and cooperation among different translocation channels, including self-doping. This clearly supports the need for many-particle approaches for reliable mechanistic investigations and for battery materials benchmarking, due to the complex nature of the diffusion and transport mechanisms. In this chapter we illustrate translocation mechanisms in detail, from which diffusion constants are evaluated.
AB - NaMPO
4 (M = Mn, Fe) olivine phosphates represent less expensive, safer and sustainable alternatives to Lithium-ion materials for battery applications. Compared to their lithium analogues, NaMPO
4 materials exist in two structures, maricite and olivine. Their implementation calls for an in-depth investigation of diffusion/conduction mechanisms, including conductivity dimensionality and how structural features map onto Na pathways. In this work, we present a refined version of our finite temperature molecular dynamics “shooting” approach, originally designed to enhance Li hopping probability in lithiated olivine compounds. We perform a comparative analysis of ion mobility in both Mn and Fe olivine materials, focused on many-particle effects. Therein, we identify main [010] diffusion channels, as well as means of inter-channel couplings, in the form of Na cross-channel [001] hopping, which markedly impact the overall mobility efficiency as measured by self-diffusion coefficients. Through introduction of antisite defects, additional pathways along [100] appear, which are specific for Na olivine phosphates, indicating limited transferability of observations made on the Li compounds, both qualitatively and quantitatively. The overall diffusion figures of merit result from the competition and cooperation among different translocation channels, including self-doping. This clearly supports the need for many-particle approaches for reliable mechanistic investigations and for battery materials benchmarking, due to the complex nature of the diffusion and transport mechanisms. In this chapter we illustrate translocation mechanisms in detail, from which diffusion constants are evaluated.
U2 - 10.1007/978-3-031-47303-6_5
DO - 10.1007/978-3-031-47303-6_5
M3 - Chapter
SN - 978-3-031-47302-9
T3 - Topics in Applied Physics
SP - 137
EP - 167
BT - Computational Design of Battery Materials
A2 - Hanaor, Dorian A.H.
PB - Springer
CY - Cham
ER -