Suppressing Ni-ion Dissolution for Long-Life Li-Metal Batteries

Nickel-rich (>90% Ni) layered cathode materials are reliable and practical candidates for application in energy-dense lithium-metal batteries (LMBs). However, their structural instability during (de)lithiation causes irreversible degradation and chemical crossover, ultimately shortening the battery lifespan. Herein, LMBs incorporating niobium-doped Li[Ni0.95Co0.03Mn0.02]O2 (Nb-NCM95) as the cathode material are reported. The doped Nb enhances the structural stability of the cathode and suppresses Ni-ion dissolution, yielding a Ni-lean solid–electrolyte interphase with compact and uniform Li deposition. Some Nb migrated to the anode, serving as a passivating material to further stabilize the Li-metal interface. Consequently, a pouch-type cell with an areal capacity of 5.38 mAh cm–2 (0.1C) and a controlled electrolyte amount-to-capacity ratio of 2.8 μL mAh–1 exhibited 80.1% capacity retention over 450 cycles. These results highlight a design principle in which minimizing Ni dissolution at the cathode helps stabilize both electrodes in energy-dense LMBs.