Methoxytriethyleneoxypropyltrimethoxysilane (MTE-TMS), a novel multifunctional additive possessing a unique functionality to simultaneously protect both Ni-rich NCM and graphite electrode surfaces. MTE-TMS improves the long-term cycling stability not only of individual half-cells of graphite and Ni-rich NCM but also of the full graphite‖Ni-rich NCM cell.
Properties and Applications
Ex-situ analysis showed that Methoxytriethyleneoxypropyltrimethoxysilane (MTE-TMS) forms a stable and thin surface protective film on the NCM851005, containing Si species, which effectively reduced crack formation, metal dissolution, and structural degradation of the cathode. MTE-TMS also forms a stable SEI layer on the graphite anode, stabilizing the graphite structure and preventing the thickening of the SEI. MTE-TMS’ effectivity, on both anode and cathode, results in superior cycling performance of the full-cells, with 1 wt% MTE-TMS in the electrolyte, delivering a high capacity of 198 mAh g?1, along with an excellent capacity retention of 84% after 100 cycles at C/5, while cycled to upper cut-off voltage of 4.25 V (4.3 vs Li+/Li). MTE-TMS has the potential to help the realization of high energy density Li-ion batteries by enabling a wider working voltage range for Ni-rich oxide cathodes[1].
