Covalent Organic Framework Featuring High Iodine Uptake for Li-Ion Battery: Unlocking the Potential of Hazardous Waste

Abstract

Management of hazardous waste is a pressing global concern, and the battle to ameliorate such waste is far from over, since it is continuously generated by the rapid growth of industrialization and the human population. Simultaneous capture of such hazardous waste and concurrent utilization in a sustainable energy application still remain the ultimate aspiration in the material field due to lack of appropriate methodology and materials from both water and the vapor phase. Herein, a new cost-effective and scalable route has been designed to synthesize a robust covalent organic framework (COF-TCO) that has been employed for iodine sequestration. The resulting adsorbent selectively captures over 98% of a trace amount of I3– from water with an excellent distribution coefficient (Kd ∼ 104 mL/g), revealing a strong affinity toward iodine. The high uptake capacity of 4.92 gg–1 was observed in the vapor phase, and efficient performance was achieved over a wide range of water systems, including potable water, lake water, river water, and seawater. Extensive experimentally guided computational studies revealed ultrahigh iodine selectivity brings out the attendant mechanistic understanding. Importantly, the iodine-captured COF-TCO was utilized for Li-ion battery applications, and it exhibited a modest specific capacity of 120 mAh/g, when tested against a lithium metal anode. The viability of scaling up lithium–iodine batteries for practical energy storage can be aided by hazardous and waste accumulated cathode materials combining safety and sustainability.