MXene-Based Electrode with Enhanced Pseudocapacitance and Volumetric Capacity for Power-Type and Ultra-Long Life Lithium Storage.

Powerful yet thinner lithium-ion batteries (LIBs) are eagerly desired to meet the practical demands of electric vehicles and portable electronic devices. However, the use of soft carbon materials in current electrode design to improve the electrode conductivity and stability does not afford high volumetric capacity due to their low density and capacity for lithium storage. Herein, we report a strategy leveraging the MXene with superior conductivity and density to soft carbon as matrix and additive material for comprehensively enhancing the power capability, lifespan and volumetric capacity of conversion-type anode. A kinetics-favorable 2D nanohybrid with high conductivity, compact density, accumulated pseudocapacitance and diffusion-controlled behavior is fabricated by coupling Ti3C2 MXene with high-density molybdenum carbide for fast lithium storage over 300 cycles with high capacities. By replacing carbonaceous conductive agent with Ti3C2 MXene, the electrodes with better conductivity and dramatically reduced thickens could be further manufactured to achieve 37-40% improvement in capacity retention and ultra-long life of 5500 cycles with extremely slow capacity loss of 0.002 % per cycle at high current rate. Ultrahigh volumetric capacity of 2460 mAh cm-3 could be attained by such MXene-based electrodes, highlighting the great promise of MXene in the development of high-performance LIBs.