Effect of Silyl Ether-functinoalized Dimethoxydimethylsilane on Electrochemical Performance of a Ni-rich NCM Cathode

Dimethoxydimethylsilane (DODSi) is used as an interface stabilizing additive through a selective HF scavenging reaction for layered Ni-rich oxide cathodes. Exsitu NMR analyses demonstrated that DODSi effectively removes HF from the electrolyte based on the matched chemical reactivity of Si with F- and O with H+. The cells employing DODSi exhibit higher specific capacity with retention than those cycled with a DODSi-free electrolyte even under insitu HF generating conditions. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma-mass spectroscopy (ICP-MS) analyses indicate that DODSi effectively protects the Ni-rich oxide cathodes against HF corrosion, resulting in improved surface stability of Ni-rich cathodes.