Interfacial Stabilization of Ni-Rich Li[Ni _0.90 Co _0.05 Mn _0.05 ]O ₂ Cathode through Synergetic Borate and Carbonate Additives

The development of stable Ni-rich cathodes is critical to the advancement of high-energy lithium-ion batteries. Their practical deployment, however, remains severely limited by rapid interfacial degradation and capacity fading that stem from their inherent surface reconstruction, oxygen evolution, strenuous phase transitions, and micro- and crystal structure degradation, especially when cycled above 4.1 V. Herein, we report an electrolyte design strategy employing tris(trimethylsilyl) borate (TMSB) and vinylene carbonate (VC) as additives to enhance the electrochemical performance of Li[Ni0.9Co0.05Mn0.05]O2 (NCM90) cathodes. Electrochemical evaluation reveals that the TMSB-VC combination achieves an exceptional capacity retention of 97.3% after 100 cycles at 0.5 C (90 mA g–1). The inclusion of TMSB in the electrolyte formulation promotes hydrofluoric acid scavenging, suppresses parasitic reactions, and promotes the formation of an inorganic-rich cathode–electrolyte interface that preserves the cathode morphology, minimizes polarization during the critical H2 ↔ H3 phase transition, and significantly enhances bulk Li+ transport kinetics. Our findings provide experimental evidence of TMSB-VC synergy, which differs from a previously reported computational prediction, to demonstrate the effectiveness of TMSB as a cathode interface stabilizing additive when paired with VC.