High-energy anode-free Li metal batteries with in-built surface-fluorinated Li-rich Mn-based cathodes

Anode-free lithium metal batteries (AF-LMBs) have been recognized as a promising approach for realizing highly safe and cost-effective lithium metal batteries with high energy density but suffer from low Coulombic efficiency (CE) and short cycle life. Here, we demonstrate high-energy and long-life AF-LMBs by leveraging the high-capacity and Li replenishment effect of surface-stabilized Li-rich Mn-based oxide (LRMO) cathodes. The irreversible capacity loss during LRMO formation, typically detrimental, is harnessed to release extra Li that deposits on the current collector, compensating for Li inventory loss and extending cell lifetime. Simultaneously, Li replenishment strategy during the formation cycle activates surface lattice oxygen, which reacts with hydrofluoroether cosolvents in a localized high-concentration electrolyte to enable a fluorinated cathode-electrolyte interphase and fluorination of the LRMO surface. As a result, a 2-ampere hour anode-free pouch cell retains 80% capacity after 260 cycles, and a 30-ampere hour pouch cell delivers 350 watt-hours per kilogram and 1200 watt-hours per liter with 84.4% retention after 180 cycles, alongside impressive low-temperature performance and rate capability. The demonstrated commercial viability of our AF-LMB showcases the essence of coherent cathode and electrolyte design for achieving high-energy and long-life AF-LMBs.