Ti₃C₂T MXene Interface Layer Driving Ultra-Stable Lithium-Iodine Batteries with Both High Iodine Content and Mass...

Lithium-iodine (Li-I₂) batteries are promising candidates for next-generation electrochemical energy storage systems due to their high energy density and the excellent kinetic rates of I₂ cathodes. However, dissolution of iodine and iodide has hindered their widespread adoption for practical applications. Herein, a Ti₃C₂T MXene foam with a three-dimensional hierarchical porous architecture is proposed as a cathode-electrolyte interface layer in Li-I₂ batteries, enabling high-rate and ultrastable cycling performance at a high iodine content and loading mass. Theoretical calculations and empirical characterizations indicate that Ti₃C₂T MXene sheets with high metallic conductivity not only provide strong chemical binding with iodine species to suppress the shuttle effect but also facilitate fast redox reactions during cell cycling. As a result, the Li-I₂ battery using a cathode with 70 wt % I₂ cycled stably for over 1000 cycles at a rate of 2 C, even at an ultrahigh loading mass of 5.2 mg cm^-2. To the best of the authors' knowledge, this is the highest reported loading at such a high iodine content. This work suggests that using a Ti₃C₂T MXene interface layer can enable the design and application of high-energy Li-I₂ batteries.