标题：Rational design of porous nitrogen-doped Ti3C2 MXene as a multifunctional electrocatalyst for Li–S chemistry
作者：Yingze Song, Zhongti Sun, Zhaodi Fan, Wenlong Cai, Yuanlong Shao, Guan Sheng, Menglei Wang, Lixian Song, Zhongfan Liu, Qiang Zhang, Jingyu Sun
单位：1. State Key Laboratory of Environment-Friendly Energy Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, PR China
2. College of Energy, Soochow Institute for Energy and Materials InnovationS (SIEMIS), Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province, Soochow University, Suzhou, Jiangsu, 215006, PR China
3. Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, PR China
4. Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
5. Center for Nanochemistry (CNC), College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, PR China
摘要：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.