Ti₃C₂Tx MXene Interface Layer Driving Ultra-Stable Lithium-Iodine Batteries with Both High Iodine Content and Mass Loading

Lithium-iodine (Li-I 2 ) batteries are promising candidates for next-generation electrochemical energy storage systems due to their high energy density and the excellent kinetic rates of I 2 cathodes. However, dissolution of iodine and iodide has hindered their widespread adoption for practical applications. Herein, a Ti 3 C 2 T x MXene foam with a three-dimensional hierarchical porous architecture is proposed as a cathode-electrolyte interface layer in Li-I 2 batteries, enabling high-rate and ultrastable cycling performance at a high iodine content and loading mass. Theoretical calculations and empirical characterizations indicate that Ti 3 C 2 T x 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-I 2 battery using a cathode with 70 wt % I 2 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 Ti 3 C 2 T x MXene interface layer can enable the design and application of high-energy Li-I 2 batteries.