Understanding mechanical stresses upon solid-state battery electrode cycling using discrete element method

Abstract

Solid-state batteries (SSBs) often fall behind conventional lithium-ion batteries (LIBs) in performance. Electrochemical cycling protocols, in particular under isostatic compression, present ample opportunities for improvement to mitigate issues like contact loss and aging among numerous other challenges. This study introduces a novel Discrete Element Method (DEM) workflow to assess the effectiveness of uniaxial and isostatic compression as proceeding electrode preparation on the conductivity and structural integrity of SSBs. Isostatic compression achieves conductivity levels comparable to uniaxial compression with significantly reduced pressure requirements. In contrast, uniaxial compression at elevated loads, while resulting in higher conductivity, subjects the particles to significant stress, increasing the risk of cracking and deformation of the SSB materials. This study shows the impact of mechanical stress during different stages of electrochemical cycling on the microstructure's integrity to provide valuable insights into electrochemistry-mechanics couplings, which can be challenging to evaluate experimentally.