Layered lithium-rich oxides, as a series of highly promising cathode material for lithium-ion batteries, attract extensive attention due to their high specific capacity and high working potential (4.6 V vs Li/Li+). However, the poor interface stability of the cathode and electrolyte seriously restricts their practical application. In this article, theoretical calculations, linear sweep voltammetry and cyclic voltammetry results indicate that tris (pentafluorophenyl) phosphine (TPFPP) is a potential dual-functional electrolyte additive to solve interface problems. The TPFPP additive can decompose preferentially on the surface of both electrodes and form uniform and stable protective films, which effectively inhibit the continuous decomposition of the electrolyte and significantly alleviate the dissolution of transition metal ions during cycling. Owing to the above effects, the capacity retention and coulombic efficiency of Li1.17Ni0.25Mn0.58O2 (LLO)/graphite (Gr) cells are improved from 62.6% and 97.7% to 90.6% and 99.8% after 200 cycles at 0.3 C (1 C = 300 mA g(-1)), respectively. This study provides a wide prospect for the application of lithium-rich materials in the future. (C) 2019 Elsevier Inc. All rights reserved.