In Situ Visualizing the Interfacial Failure Mechanism and Modification Promotion of LAGP Solid Electrolyte toward Li Metal Anode

摘要

In-depth understanding the failure process of solid-state electrolyte (SSE) andproviding potential solutions are crucial for the development of solid-statebatteries (SSBs). Typical techniques are powerful to investigate the chemical/electrochemical degradation of SSE. While, mechanical failure, which wouldundoubtedly affect battery performance, is difficult to detect by normaltechniques and lack effective characterizations. Herein, via in situ electrochemicalSEM, the dynamic failure process of SSE is observed, revealing thecontinuously generated side-reaction layer and the stress-induced cracksare the main origins. C_3N_4 (CN) is introduced as the modification layer for Liand SSE. Via in situ scanning electron microscope, Li growth is regulated byCN from dendrite-like to particulate-like growth. The properties of electronictransportation and ionic migration in CN are quantitatively measured, andCN promotion mechanism is revealed. Thanks to CN layer, the interfacialside-reaction is restrained, simultaneously, Li~+ flux becomes well-distributedfor dense Li deposition, preventing stress-induced mechanical failure in SSE.Li symmetrical batteries with CN can endure the maximum current densityup to 2.0 mA cm~（?2） and stably cycle for 3000 h at 300 μA cm~（?2）. This worksuggests a promising method to circumvent SSE degradation against Li andopen opportunities for future SSBs.