A Li metal-SiO<i>_x</i> hybrid anode enabling synergistic plating/alloying dual-mechanism lithium storage.

Abstract

Balancing specific energy and cycle durability remains a critical challenge for practical battery systems, as conventional single-mechanism anodes struggle to optimize both simultaneously. Here, we engineer a symbiotic Li-SiO<i>_x</i> hybrid anode enabling spatiotemporally coordinated Li metal plating and Li-ion alloying. The preferential lithiated Li<i>_x</i>Si forms a Li⁺-conductive network, guiding and confining lithium nucleation beneath the SiO<i>_x</i> layer. This precise control over Li plating replenishes active lithium inventory, stabilizing electrochemical reactions and minimizing Li loss. When paired with a LiNi_0.8Co_0.1Mn_0.1O₂ cathode (4 milliampere-hours per square centimeter), the full cell achieves 50% higher specific energy than SiO<i>_x</i>-based lithium-ion batteries while retaining 80% capacity after 900 cycles at a lean negative/positive ratio of 1.5, outperforming state-of-the-art Li-ion and Li-metal battery systems. A pouch cell exhibits stable cycling over 600 cycles at 0.5C, validating its practicality. Our findings pioneered a universal hybrid anode design paradigm with coupled reaction mechanisms, effectively addressing the longstanding energy durability trade-off in next-generation batteries.