Vinyltrimethylsilane as a novel electrolyte additive for improving interfacial stability of Li-rich cathode working in high voltage

Abstract

Boosting the interfacial stability between electrolyte and Li-rich cathode material at high operating voltage is vital important to enhance the cycling stability of Li-rich cathode materials for high-performance Li-ion batteries. In this work, vinyltrimethylsilane as a new type of organic silicon electrolyte additive is studied to address the interfacial instability of Li-rich cathode material at high operating voltage. The cells using vinyltrimethylsilane additive shows the high capacity retention of 73.9% after 300 cycles at 1 C, whereas the cells without this kind of additive only have the capacity retention of 58.9%. The improvement of stability is mainly attributed to the additive helping to form a more stable surface film for Li-rich cathode material, thus avoiding direct contact between the electrolyte and the cathode material, slowing down the dissolution of metal ions and the decomposition of the electrolyte under high operating voltage. Our findings in this work shed some light on the design of stable cycling performance of Li-rich cathode toward advanced Li-ion batteries.