Advancing lithium-sulfur battery efficiency: utilizing a 2D/2D g-C₃N₄@MXene heterostructure to enhance sulfur evolution reactions and regulate polysulfides under lean electrolyte conditions

Lithium-sulfur batteries (LSBs) show promise for achieving a high energy density of 500 W h kg(-1), despite challenges such as poor cycle life and low energy efficiency due to sluggish redox kinetics of lithium polysulfides (LiPSs) and sulfur's electronic insulating nature. We present a novel 2D Ti3C2 Mxene on a 2D graphitic carbon nitride (g-C3N4) heterostructure designed to enhance LiPS conversion kinetics and adsorption capacity. In a pouch cell configuration with lean electrolyte conditions (similar to 5 mu L mg(-1)), the g-C3N4-Mx/S cathode exhibited excellent rate performance, delivering similar to 1061 mA h g(-1) at C/8 and retaining similar to 773 mA h g(-1) after 190 cycles with a Coulombic efficiency (CE) of 92.7%. The battery maintained a discharge capacity of 680 mA h g(-1) even at 1.25 C. It operated reliably at an elevated sulfur loading of 5.9 mg cm(-2), with an initial discharge capacity of similar to 900 mA h g(-1) and a sustained CE of over 83% throughout 190 cycles. Postmortem XPS and EIS analyses elucidated charge-discharge cycle-induced changes, highlighting the potential of this heterostructured cathode for commercial garnet LSB development.