A Robust, Freestanding MXene-Sulfur Conductive Paper for Long-Lifetime Li-S Batteries

Freestanding, robust electrodes with high capacity and long lifetime are of critical importance to the development of advanced lithium-sulfur (Li-S) batteries for next-generation electronics, whose potential applications are greatly limited by the lithium polysulfide (UPS) shuttle effect. Solutions to this issue have mostly focused on the design of cathode hosts with a polar, sulfurphilic, conductive network, or the introduction of an extra layer to suppress LIPS shuttling, which either results in complex fabrication procedures or compromises the mechanical flexibility of the device. A robust Ti3C2Tx/S conductive paper combining the excellent conductivity, mechanical strength, and unique chemisorption of LiPSs from MXene nanosheets is reported. Importantly, repeated cycling initiates the in situ formation of a thick sulfate complex layer on the MXene surface, which acts as a protective membrane, effectively suppressing the shuttling of LiPSs and improving the utilization of sulfur. Consequently, the Ti3C2Tx/S paper exhibits a high capacity and an ultralow capacity decay rate of 0.014% after 1500 cycles, the lowest value reported for Li-S batteries to date. A robust prototype pouch cell and full cell of Ti3C2Tx/S paper//lithium foil and prelithiated germanium are also demonstrated. The preliminary results show that Ti3C2Tx/S paper holds great promise for future flexible and wearable electronics.