3D microstructure design of lithium-ion battery electrodes assisted by X-ray nano-computed tomography and modelling

Xuekun Lu,Kieran B O’Regan,Thomas M M Heenan,Gareth Hinds,Julia S Weaving,Emma Kendrick,Antonio Bertei,Dan J L Brett,Paul R Shearing,Sohrab R Daemi,Chun Tan,Donal P Finegan

doi:10.1038/s41467-020-15811-x

Abstract

Driving range and fast charge capability of electric vehicles are heavily dependent on the 3D microstructure of lithium-ion batteries (LiBs) and substantial fundamental research is required to optimise electrode design for specific operating conditions. Here we have developed a full microstructure-resolved 3D model using a novel X-ray nano-computed tomography (CT) dual-scan superimposition technique that captures features of the carbon-binder domain. This elucidates how LiB performance is markedly affected by microstructural heterogeneities, particularly under high rate conditions. The elongated shape and wide size distribution of the active particles not only affect the lithium-ion transport but also lead to a heterogeneous current distribution and non-uniform lithiation between particles and along the through-thickness direction. Building on these insights, we propose and compare potential graded-microstructure designs for next-generation battery electrodes. To guide manufacturing of electrode architectures, in-situ X-ray CT is shown to reliably reveal the porosity and tortuosity changes with incremental calendering steps.

Highlights

Driving range and fast charge capability of electric vehicles are heavily dependent on the 3D microstructure of lithium-ion batteries (LiBs) and substantial fundamental research is required to optimise electrode design for specific operating conditions
The pore and carbon-binder domain (CBD) were treated as a single phase that was assumed to be filled with electrolyte[23,26], which may lead to unrepresentative microstructures and mass transport performance
This study aims to drive the advancement of battery performance in the perspectives of both electrode design and manufacturing

Summary

Introduction

Driving range and fast charge capability of electric vehicles are heavily dependent on the 3D microstructure of lithium-ion batteries (LiBs) and substantial fundamental research is required to optimise electrode design for specific operating conditions. We have developed a full microstructure-resolved 3D model using a novel X-ray nano-computed tomography (CT) dual-scan superimposition technique that captures features of the carbonbinder domain This elucidates how LiB performance is markedly affected by microstructural heterogeneities, under high rate conditions. The elongated shape and wide size distribution of the active particles affect the lithium-ion transport and lead to a heterogeneous current distribution and non-uniform lithiation between particles and along the through-thickness direction. Building on these insights, we propose and compare potential graded-microstructure designs for next-generation battery electrodes. To accurately correlate the microstructure with performance, a more practical solution is required

Objectives

Methods

Results