The role of grain boundaries in solid-state Li-metal batteries

fib sem images of the finite element analysis of the current density distribution

Despite the potential advantages promised by solid-state batteries, the success of solid-state electrolytes has not yet been fully realised.  This is due in part to the lower ionic conductivity of solid electrolytes.  In many solid superionic conductors, grain boundaries are found to be ionically resistive and hence contribute to this lower ionic conductivity - additionally, in spite of the hope that solid electrolytes would inhibit lithium filaments, in most scenarios their growth is still observed, and in some polycrystalline systems this is suggested to occur along grain boundaries.

It is apparent that grain boundaries affect the performance of solid-state electrolytes, however, a deeper understanding is lacking.

In 'The role of grain boundaries in solid-state Li-metal batteries', published in Materials Futures), Emily Milan and Professor Mauro Pasta explore the current theories relating to grain boundaries in solid-state electrolytes.  They also address some of the challenges which arise when trying to investigate the role of solid-state electrolytes.

Glasses are presented as a possible solution to reduce the effect of grain boundaries in electrolytes.  Future research directions are suggested which will both aid an understanding of the role of grain boundaries, and diminish their contribution in cases where they are detrimental.