Cyclic Aminosilane‐Based Additive Ensuring Stable Electrode–Electrolyte Interfaces in Li‐Ion Batteries

Abstract

Ni‐rich cathodes are considered feasible candidates for high‐energy‐density Li‐ion batteries (LIBs). However, the structural degradation of Ni‐rich cathodes on the micro‐ and nanoscale leads to severe capacity fading, thereby impeding their practical use in LIBs. Here, it is reported that 3‐(trimethylsilyl)‐2‐oxazolidinone (TMS‐ON) as a multifunctional additive promotes the dissociation of LiPF6, prevents the hydrolysis of ion‐paired LiPF6 (which produces undesired acidic compounds including HF), and scavenges HF in the electrolyte. Further, the presence of 0.5 wt% TMS‐ON helps maintain a stable solid–electrolyte interphase (SEI) at Ni‐rich LiNi0.7Co0.15Mn0.15O2 (NCM) cathodes, thus mitigating the irreversible phase transformation from layered to rock‐salt structures and enabling the long‐term stability of the SEI at the graphite anode with low interfacial resistance. Notably, NCM/graphite full cells with TMS‐ON, which exhibit an excellent discharge capacity retention of 80.4%, deliver a discharge capacity of 154.7 mAh g−1 after 400 cycles at 45 °C.