Stabilizing ultrahigh-nickel layered oxide cathodes for high-voltage lithium metal batteries

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 degrees C and 91.6% after 100 cycles at 60 degrees C in the voltage range of 2.8-4.4 V in Li parallel to 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 about 209 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, long-lasting LMBs.

Automated summary

The study demonstrates that utilizing advanced electrolyte can form protective and stable interfaces in ultra-high-Ni cathodes, which enhances the capacity retention and cycling performance of lithium metal batteries. Forming conductive electrode/electrolyte interfaces in NC cathode enables high reversible capacity.