Phase Separating Electrode Materials Chemical Inductors

TL;DR

This paper reveals chemical inductive effects in phase separating ion intercalation materials like LFP and LTO, explaining their origin through mechanistic modeling and linking it to observed impedance phenomena.

Contribution

It provides the first mechanistic explanation for inductive effects in phase separating electrode materials, supported by analytical modeling.

Findings

Inductive effects occur within the miscibility gap of phase separating materials.

These effects are linked to fast intercalation and slow diffusion relaxation phenomena.

The study explains why inductive effects are absent outside the miscibility gap.

Abstract

We discover presence of chemical inductive effects in phase separating ion intercalation energy storage materials, specifically in lithium iron phosphate (LFP) and also lithium titanate oxide (LTO). These materials features fast (de)intercalation and slow diffusion relaxation phenomena which are prerequisites for observing such inductive effects. Presented finding is supported by the mechanistic model and analytical reasoning indicating that all equilibrium states that lay inside the miscibility gap of the phase separating material exhibit strong inductive response in the low frequency part of spectrum. We also explain why such inductive effects are not observed outside the miscibility gap. This letter presents the first mechanistic reasoning of previously reported electrode level experimental observation of inductance during impedance measurements at low currents.