In situ constructed organic/inorganic hybrid interphase layers for high voltage Li-ion cells

Abstract

High cut-off charge potential usually means high viable specific capacity and energy for the cathode materials. However, electrode/electrolyte interface reactions will be triggered at high potentials, leading to electrolyte decomposition, increased charge transfer resistance and accelerated transition metal dissolution. Therefore, a durable and uniform interphase layer is essential to suppress the interfacial reactions. We herein address these issues by using tetrakis (trimethylsiloxy) titanium (TT) as a multifunctional electrolyte additive to form a thin and uniform interface layer on the electrodes. The results of time-of-flight secondary ion mass spectroscopy and X-ray photoelectron spectroscopy illustrate that the film is composes of organic C3H9Si and inorganic TiO2. Owning to the presence of the durable and self-curable organic/inorganic hybrid interphase on both the Li1.17Ni0.25Mn0.58O2 (LLO) cathode and the graphite anode, the capacity retention of the LLO/graphite cell is enhanced from 33% to 81% in 150 cycles. These findings provide a new approach to create hybrid high performance interphase for the high energy density batteries.