Rational design of porous nitrogen-doped Ti3C2 MXene as a multifunctional electrocatalyst for Li-S chemistry

The detrimental shuttle effect and retarded sulfur reaction kinetics in lithium-sulfur (Li-S) chemistry mainly lead to inferior electrochemical performances, posing a fatal threat to the practical application of Li-S batteries. Herein, porous N-doped Ti3C2 MXene (P-NTC) has been realized by a scalable sacrificial templating route, resulting in the rational design of active electrocatalyst for Li-S chemistry. Benefiting from the superb electron conductivity, large surface area and strong interaction with lithium polysulfides (LiPSs), P-NTC can trigger the surface-mediated redox reaction of LiPSs. Moreover, the homogenous nitrogen doping on Ti3C2 gives rise to enhanced interfacial interaction with Li atom and lowered dissociation barrier for Li2S. Therefore, the template-derived P-NTC not only acts as an effective LiPS immobilizer but also serves as a multifunctional electrocatalyst to propel the nucleation and decomposition of Li2S in discharge and charge processes, respectively. As expected, thus-fabricated S/P-NTC cathode maintains a low capacity decay of only 0.033% per cycle at 2.0 C over 1200 cycles. In further contexts, our ability to tune the sulfur mass loadings enables fabricated cathodes to harvest a high areal capacity of 9.0 mAh cm(-2), holding great promise in future practical applications.