Multifunctional electrolyte additive for improved interfacial stability in Ni-rich layered oxide full-cells
Hieu Quang Pham, Marta Mirolo, Mohamed Tarik, Mario El Kazzi, Sigita Trabesinger
Abstract
Improving the interfacial stability between the electrode and the electrolyte at high voltage is a key to successfully obtain high energy-density Li-ion batteries. Therefore, this study is dedicated to a novel multifunctional electrolyte additive, methoxytriethyleneoxypropyltrimethoxysilane (MTE-TMS), able to stabilize the interface of both Ni-rich layered LiNi0.85Co0.1Mn0.05O2 (NCM851005) cathode and graphite anode in a full-cell. Electrochemical tests reveal that the addition of 1 wt% MTE-TMS significantly improves the long-term cycling stability of the graphite‖NCM851005 full-cell, with an achieved maximum capacity of 198 mAh g−1 and its excellent capacity retention of 84% after 100 cycles at C/5 using upper voltage cut-off of 4.3 V vs Li+/Li. In contrast, the standard electrolyte in absence of MTE-TMS leads to a rapid performance fade. The significantly improved electrochemical performance is attributed to the formation of a stable surface protective film at both the cathode and the anode surfaces upon long-term cycling in elevated voltage window, and thus suppressing the electrolyte decomposition at and structural degradation of both cathode and anode, resulting as well in reduced transition metal transfer between the two electrodes.