Polyaniline-Modified MXene/Carbon Nanotube Scaffold Enabling High-Rate and Long-Cycle Zinc-Iodine Batteries

Aqueous zinc-iodine (Zn-I2) batteries are attractive for large-scale energy storage because of their low cost and inherent safety. However, the practical use of an I2 cathode is severely restricted by poor electronic conductivity and the shuttle effect of soluble polyiodides. Herein, a synergistic scaffold composed of MXene and carbon nanotubes (CNTs) modified with protonated polyaniline (PANI) via electrostatic interactions was designed. The MXene/CNT scaffold ensures overall conductivity and structural integrity. The protonated PANI immobilizes iodine species through nitrogen-containing groups and accelerates their interconversion, effectively suppressing the shuttle effect. The MXene/CNTs/PANI-I2 cathode with an iodine loading of 43.96 wt % achieves a superior specific capacity of 150 mAh g-1 at a high rate of 20 C as well as excellent cycling stability over 10 000 cycles. This work offers a viable strategy for developing stable I2 cathodes for high-performance Zn-I2 batteries.