Li_XGe containing ion-conductive hybrid skin for high rate lithium metal anode

Lithium metal is regarded as a promising anode material for high energy density battery systems owing to its ultrahigh theoretical capacity (3860 mAh g⁻¹). Unfortunately, problematic dendrite is the key obstacle for practical utilization. In general, it is taken for grant that the growth of lithium dendrites is accelerated at high current densities. Here, we built an ion-conductive skin, containing germanium (Ge), polyacrylic acid (PAA) and polyvinyl alcohol (PVA), named Ge@PAA-PVA, to tackle the dendrite issues. In the hybrid skin, Ge particles work as boosted ionic migrating channels to manage the Li-ion flux for realizing the stable and dendrite-free morphology, while PAA-PVA organic matrix as a soft base for weakening side reactions. Taking advantages of this hybrid skin layer, Li|LiCoO₂ full cells with Ge@PAA-PVA grafted anode deliver an excellent cycle performance with 81.5% capacity retention at 2C and 74% capacity retention at 5C over 500 cycles. This work may open a new avenue for commercial utilization of Li metal with high retention of capacity and ultra-long lifespan in rechargeable high-energy-density lithium metal batteries.