A stabilized high-energy Li-polyiodide semi-liquid battery with a dually-protected Li anode

Li-polyiodide batteries are attractive because of their high energy density and excellent rate performance. Nevertheless, the polyiodide shuttle effect and Li dendrite growth over cycling result in fast degradation of the Li anode and a short cycle life. Here we report a facile yet efficient design of high-energy membrane-free Li-polyiodide battery, in which the Li anode is shielded by a pre-deposited indium (In) layer and a graphene paper layer. The proof-of-concept semi-liquid battery with such a dual-protection strategy demonstrates a remarkably enhanced cycling stability for the reasons: (i) the In layer is capable of mitigating the Li dendrite growth and resisting the polyiodide shuttle attack; and (ii) the graphene paper physically suppresses the anode surface evolution and enables the formation of a separated passivation layer. Consequently, the battery can operate with a concentrated catholyte of 6 M I⁻and achieves a volumetric energy density as high as 165.3 Wh L⁻¹(1.5 C) for 100 cycles. The high performances achieved suggest the aprotic Li-polyiodide battery with a compact and robust architecture shows the potential for various energy storage applications.