High-performance metal–iodine batteries enabled by a bifunctional dendrite-free Li–Na alloy anode

Abstract

Rechargeable aprotic alkali metal (Li and Na)–iodine (AM–I₂) batteries with high theoretical capacity and specific energy density have emerged as one of the promising energy storage technologies. However, their application has been severely limited by dendrite formation on alkali metal anodes. By infusing a eutectic Li–Na alloy into a carbon cloth (CC), we developed a novel bifunctional Li–Na alloy-CC anode for Li/Na–iodine batteries with significantly enhanced electrochemical performance. Specifically, the LiNa-CC anode in a symmetric battery exhibited an ultra-stable cycling stability up to 800 and 1650 hours for Li and Na plating/stripping at a current density of 40 and 20 mA cm⁻², respectively. When coupled with an iodine cathode in a Li/Na–iodine battery, the LiNa-CC anode exhibited a significantly improved cycling stability with 84.8% and 83.3% capacity retentions after 2000 cycles at a current density of 5C for Li–I₂ and Na–I₂ batteries, respectively. This work provides new perspectives for developing multifunctional dendrite-free alkali metal–iodine batteries.