1 research outputs found
Blocking Directional Lithium Diffusion in Solid-State Electrolytes at the Interface: First-Principles Insights into the Impact of the Space Charge Layer
Understanding the degradation mechanisms in solid-state
lithium-ion
batteries at interfaces is fundamental for improving battery performance
and for designing recycling methodologies for batteries. A key source
of battery degradation is the presence of the space charge layer at
the solid-state electrolyte–electrode interface and the impact
that this layer has on the thermodynamics of the electrolyte structure.
Currently, Li10GeP2S12 in its pristine
form has one of the highest lithium conductivities and has been used
as a template for designing even higher conductivity derived structures.
However, being an ionic material with mostly linear diffusion, it
is prone to path-blocker defects, which we show here to be especially
prevalent in the space charge layer. We analyze the thermodynamic
properties of a number of path-blocker defects using density functional
theory and their potential crystal decomposition and find that the
presence of an electrostatic potential in the space charge layer elevates
the likelihood of existence of these defects, which otherwise would
not be likely to form in the bulk of the electrolyte away from electrodes.
We use ab initio molecular dynamics to assess the
impact of these defects on the diffusivity of the crystal and find
that they all reduce the lithium diffusivity. While our work focuses
on Li10GeP2S12, it is relevant to
any solid-state electrolyte with mainly linear diffusion