The new imaging study revealed that the initiation and propagation of the dendrite cracks are separate processes, driven by distinct underlying mechanisms. 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'.
Dominic Melvin
You can read more about this game-changing research by visiting the University's news website: 'New study could help unlock 'game-changing' batteries for electric vehicles and aviation'.