Outstanding electrochemical performances of the all-solid-state lithium battery using Ni-rich layered oxide cathode and sulfide electrolyte

Abstract Although Ni-rich layered oxides with high specific capacity are considered to have potential application in all-solid-state lithium batteries (ASSLB) using sulfide electrolyte, the Ni-rich layered oxide/sulfide electrolyte interfacial instability is still a serious issue. To effectively improve the interfacial stability and electrochemical performances, LiNi0·8Co0·1Mn0·1O2 (NCM) precursor is for the first time coated with nano-thickness LiCoO2 (LCO) precursor to form core-shell NCM@LCO precursor, which is then calcined to form NCM@LCO material with Ni-poor surface. Subsequently a small amount of LiNbO3 (LNO) is further coated on the surface of NCM@LCO particles to form NCM@LCO@LNO material. As expected, NCM@LCO@LNO cathode displays the outstanding electrochemical performances especially cycle stability (capacity retention of 80% after 585 cycles at 0.612 mA cm−2), indicating that this strategy is very effective to construct high performance Ni-rich layered oxide cathodes for ASSLB using sulfide electrolyte. To our knowledge, the excellent results are firstly reported in the references related to ASSLB using sulfide electrolyte. Moreover, the performance improvement mechanism is also investigated by Raman spectra in combination with cyclic voltammetry. Our study reveals that this strategy can effectively suppress the irreversible phase transformation and interface side reaction for Ni-rich layered oxides.