A stabilized cathode electrolyte interphase (CEI) formed on the cathode electrode by virtue of effective electrolyte additives is crucial for prolonging the lifespan of lithium-ion battery adopting high energy density Ni-rich cathode materials. Here, we report a novel multifunctional additive trimethylsilyl 2-(fluorosulfonyl)difluoroacetate (TMSFS) for LiNi 0.9 Co 0.05 Mn 0.05 O 2 (NCM90). By adding 0.5% TMSFS, the NCM90 electrode shows an enhanced capacity retention of 85.1% at 1C up to 200 cycles, superior over that of 73.1% for baseline electrolyte. The improvement on cycling performance can be also achieved at harsh testing conditions (e.g., 60 °C and even a high voltage of 4.4 V), along with fast electrode kinetics in the presence of TMSFS. It's demonstrated that TMSFS additive could scavenge the undesired H 2 O, PF 5 and HF species in electrolyte, alleviating the subsequent damages to both cathode-electrolyte interface and NCM90 cathode structure. More importantly, a compact, inorganics-enriched CEI layer formed in TMSFS-added electrolyte is further revealed, rationalizing the impressive improvement in electrochemical performance. Furthremore, we also prove the effectiveness of TMSFS additive for graphite||NCM90 full cells. • A novel electrolyte additive TMSFS for NCM90 cathode. • Scavenging the undesired H 2 O, PF 5 and HF species in electrolyte. • A compact inorganics-enriched CEI layer formed in TMSFS-added electrolyte. • Faster kinetics and improved cycling stability enabled by TMSFS additive.