Omni-functional simultaneous interfacial treatment for enhancing stability and outgassing suppression of lithium-ion batteries

Ni-rich layered oxides in lithium-ion batteries have problems with gas generation and electrochemical performance reduction due to residual lithium's reaction on the surface with the electrolyte. To address this issue, in this study, the Acid solvent evaporation (ASE) method has been proposed as a potential method to remove residual lithium while promoting the formation of a new LiNO3-derived coating layer on the cathode surface. The reduction of residual lithium using the ASE method and the construction of a LiNO3-derived coating layer suppresses gas evolution caused by the side effects of the electrolyte, improves electrochemical performance, and improves thermal stability by facilitating the smooth movement of lithium ions. Furthermore, the structural stability and resistance change due to the LiNO3-derived coating layer effects is guaranteed through cycling and DCIR of the pouch cell. As a result, compared to Pristine, the capacity retention of coin cells increased by 8% after 100 cycles, and pouch cells increased by 25% after 160 cycles. In addition, after cycling the pouch cell, CO2 gas has significantly reduced by about 30% compared to Pristine using gas chromatography. The ASE method effectively forms a robust LiNO3-derived coating layer on the cathode active material, which helps minimize electrolyte reactivity, suppress CO2 emissions, enhance surface structure stability, improve thermal stability, and improve overall battery performance.