One-step synthesis of Li2MoO4-coated and Mo-doped LiNi0.8Co0.1Mn0.1O2 single-crystals using Li2MoO4 as a sacrificial molten salt

Abstract

Molten salt synthesis is a universal approach to synthesizing single-crystal cathodes. However, complicated processes, such as washing to remove the molten salt and repeated heat treatments, have hindered its practical application in the synthesis of high-Ni NCMs. In this work, using LiNi0.8Mn0.1Co0.1O2 as a model material, a one-step strategy was developed to prepare Li2MoO4-coated and Mo6+-doped single-crystals, where the formation of single crystals, coating, and doping are achieved simultaneously by adding 2% Li2MoO4 as a sacrificial molten salt. The proposed one-step strategy does not require washing to remove molten salt and repeated heat treatment. Furthermore, Li2MoO4 coating and Mo6+ doping can further enhance the structural/interfacial stability and the electrode kinetics of single-crystal LiNi0.8Mn0.1Co0.1O2. Therefore, the cyclic stability (83% after 200 cycles at 1C) and rate performance (169 mAh·g−1 at 10C) of single-crystal LiNi0.8Co0.1Mn0.1O2 is superior to that of polycrystal LiNi0.8Co0.1Mn0.1O2 prepared without the addition of Li2MoO4 (67% and 134 mAh·g−1). This one-step strategy using sacrificial molten salts reveals an attractive pathway for developing single-crystal electrode materials with stable structure/interface and good electrode kinetics.