Nitrogen-doped Ti₃C₂T_x coated with a molecularly imprinted polymer as efficient cathode material for lithium-sulfur batteries

Lithium-sulfur batteries, known for their high energy density, low cost, and minimal environmental impact, are emerging as a promising alternative to lithium-ion batteries. However, their commercial viability remains a formidable scientific challenge mainly because of the sluggish reaction kinetics at the cathode and the so-called “shuttling effect” of soluble polysulfides, which results in capacity decay and a shortened lifespan. Herein, molecular imprinting with Li₂S₈ as a target molecule in combination with a two-dimensional material, MXene, is proposed to overcome these issues. Molecularly imprinted polymer-coated N-Ti₃C₂T_x was successfully synthesized and demonstrated to exhibit appealing electrochemical performance, namely a high specific capacity of 1095 mAh g^-1 at 0.1 C and extended cycling stability (300 mAh g^-1 at 1.0 C after 300 cycles). X-ray photoelectron spectroscopy was applied to elucidate the underlying mechanisms and proved that Li₂S₈-imprinted polymer polyacrylamide serves as a polysulfide trap through strong chemical affinity towards the long-chain lithium polysulfides, while N-doped Ti₃C₂T_x promotes the redox kinetics by accelerating the conversion of lithium polysulfides. This distinct interfacial strategy is expected to ensure more effective and stable Li-S batteries.