Prolonged lifespan of initial-anode-free lithium-metal battery by pre-lithiation in Li-rich Li2Ni0.5Mn1.5O4 spinel cathode.

Abstract

Anode-free lithium metal batteries (AF-LMBs) can deliver the maximum energy density. However, achieving AF-LMBs with a long lifespan remains challenging because of the poor reversibility of Li+ plating/stripping on the anode. Here, coupled with a fluorine-containing electrolyte, we introduce a cathode pre-lithiation strategy to extend the lifespan of AF-LMBs. The AF-LMB is constructed with Li-rich Li2Ni0.5Mn1.5O4 cathodes as a Li-ion extender; the Li2Ni0.5Mn1.5O4 can deliver a large amount of Li+ in the initial charging process to offset the continuous Li+ consumption, which benefits the cycling performance without sacrificing energy density. Moreover, the cathode pre-lithiation design has been practically and precisely regulated using engineering methods (Li-metal contact and pre-lithiation Li-biphenyl immersion). Benefiting from the highly reversible Li metal on the Cu anode and Li2Ni0.5Mn1.5O4 cathode, the further fabricated anode-free pouch cells achieve 350 W h kg-1 energy density and 97% capacity retention after 50 cycles.