Mxene-derived stepwise Transformation: Customizing ultrathin TiS2/C nanosheets for high-capacity lithium-ion batteries

As a typical two-dimensional transition metal sulfide, TiS 2 holds immense potential for lithium-ion batteries (LIBs) owing to its high theoretical capacity and large interlayer spacing. Nevertheless, intrinsic limitations, including poor intrinsic electronic conductivity and structural degradation hinder its development in high-energy-density and long-lasting LIBs. Herein, we prepared an in-situ derived TiS 2 /C composite electrode by harnessing few-layer Ti 3 C 2 MXene as a sacrificial template. Through controlled sequential S substitution within a S-rich environment, we achieved the uniform encapsulation of ultrathin TiS 2 nanosheets within a conductive amorphous carbon matrix. This unique architecture establishes robust and conductive networks that ensure excellent structural integrity while enabling rapid electron/ion transfer kinetics. In addition, the theoretical calculations of binding energy evolution unambiguously confirm the reaction pathways: Ti 3 C 2 MXene→intermediate TiO 2 /C→TiS 2 /C. As a result, the TiS 2 /C electrode delivers a high initial discharge capacity of 921.9 mAh g −1 at 100 mA g −1 , with a capacity retention rate of 72.7 % after 200 cycles. Remarkably, it sustains discharge capacity of 631.2 mAh g −1 after 1000 cycles at 500 mA g −1 , showcasing superior high-rate cyclability. This work paves the way for the development of energy-dense and long-cycling-life LIBs.