Mitigating Li-Rich Layered Cathode Capacity Loss by Using a Siloxane Electrolyte Additive

The instability of the electrode-electrolyte interface in high-voltage cathode materials significantly hinders the development of high-energy-density lithium-ion batteries (LIBs). In this study, 1,3-diphenyl-1,1,3,3-tetramethyldisiloxane (DTS) is employed as an electrolyte additive to enhance the cycling stability and capacity retention for Li||LLO (Li-rich layered oxide) batteries operating at 4.8 V. Theoretical calculations show that DTS can preferentially oxidize on the surface of the cathode. The oxidation forms a robust cathode electrolyte interface (CEI) on the LLO surface, significantly mitigating cracking, regeneration, and irreversible phase transitions of the LLO cathode. As anticipated, the Li||LLO batteries with the DTS electrolyte exhibit a capacity retention of 85.4% after 100 cycles at 4.8 V compared to the baseline electrolyte (45.2%). Furthermore, these batteries demonstrate superior capacity retention after 100 cycles at 4.8 V, even with the presence of 1000 ppm of H2O.