Dendrite initiation and propagation in lithium metal solid-state batteries

Dominic Melvin and Professor Sir Peter Bruce are co-authors of this paper* which describes their breakthrough in understanding why solid state batteries fail.  The paper describes how they and their collaborators used X-ray tomography to visualise dendrite failure in unprecedented detail during the battery charging process.

The new imaging study revealed that the initiation and propagation of the dendrite cracks are separate processes, driven by a distinct underlying mechanism.  Dendrite cracks initiate when lithium accumulates in sub-surface pores.  When those pores become full, further charging of the battery increases the pressure, leading to cracking.  In contrast, propagation occurs with lithium only partially filling the crack, through a wedge-opening mechanism which drives the crack open from the rear.

'While pressure at the lithium anode can be good to avoid gaps developing at the interface with the solid electrolyte on discharge, our results demonstrate that too much pressure can be detrimental, making dendrite propagation and short-circuit on charging more likely'

The University has also published an article on this paper: 'New study could help unlock 'game-changing' batteries for electric vehicles and aviation'.  

*'Dendrite initiation and propagation in lithium metal solid-state batteries' as published in Nature.