Origin of O2 Generation in Sulfide‐Based All‐Solid‐State Batteries and its Impact on High Energy Density

MDR Open Deposited

The cathode surface of sulfide-based all-solid-state batteries (SBs) is
commonly coated with amorphous-LiNbO3 in order to stabilize
charge–discharge reactions. However, high-voltage charging diminishes the
advantages, which is caused by problems with the amorphous-LiNbO3
coating layer. This study has investigated the degradation of
amorphous-LiNbO3 coating layer directly during the high-voltage charging of
SBs. O2 generation via Li extraction from the amorphous-LiNbO3 coating
layer is observed using electrochemical gas analysis and electrochemical X-ray
photoelectron spectroscopy. This O2 leads to the formation of an oxidative
solid electrolyte (SE) around the coating layer and degrades the battery
performance. On the other hand, elemental substitution (i.e.,
amorphous-LiNbxP1-xO3) reduces O2 release, leading to stable high-voltage
charge–discharge reactions of SBs. The results have emphasized that the
suppression of O2 generation is a key factor in improving the energy density
of SBs.

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Date published
  • 08/07/2024
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  • Version of record (Published version)
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