PNNL

Abstract

Rechargeable lithium (Li) metal batteries (LMBs) with ultrahigh-nickel (Ni) layered oxide cathodes offer a great opportunity for applications in electrical vehicles. However, increasing Ni content inherently arouses a tradeoff between specific capacity and electrochemical cyclability due to the aggressive side reactions with electrolyte contributed by the highly reactive Ni species. Here, a protective and stable cathode/electrolyte interphase featuring enriched and evenly-distributed LiF is in-situ formed on ultrahigh-Ni cathode LiNi0.94Co0.06O2 (NC) with an advanced ether-based localized high-concentration electrolyte (LHCE), which concurrently shows good compatibility with Li metal anode. Subsequently, the NC cathode can deliver high capacity retentions of 81.4 % after 500 cycles at 25 °C and 91.7% after 100 cycles at 60 °C in the voltage range of 2.8-4.4 V in Li||NC cells at 1C cycling rate (1.5 mA cm-2). Meanwhile, the conductive electrode/electrolyte interphases formed in LHCE enable a high reversible capacity of 208.6 mAh g-1 at 3C charging rate. This work provides an effective approach and important insight from the perspective of in-situ ultrahigh-Ni cathode/electrolyte interphase protection for high energy-density and long-lasting LMBs.