NiMn-Layered Double Hydroxides Chemically Anchored on Ti3C2 MXene for Superior Lithium Ion Storage

The aggregation and low conductivity of layered double hydroxides (LDHs) limit their practical applications in energy conversion and storage. Herein, NiMn-LDHs were anchored on the surface of Ti3C2 MXene sheets using an in situ crystallization process. Chemical bonds have been demonstrated as the main linkage between MXene and NiMn-LDH to inhibit structure degradation. Furthermore, the size of NiMn-LDH nanosheets was reduced with the incorporation of MXene due to heterogeneous nucleation, resulting in faster ion transport and electron transfer. As expected, the rate performance and cycle stability of this hybrid material are significantly improved (1330 mAh g(-1) at 0.1 A g(-1) and 88.6% capacity retention over 3000 cycles), compared with those of the MXene and NiMn-LDH mixture (875 mAh g(-1) at 0.1 A g(-1) and 41.8% left after 3000 cycles), indicating that the oxygen bridge is critical in improving the internal cohesion of the hybrid materials. A lithium-ion capacitor equipped with a NiMn-LDH/MXene anode and an activated carbon (AC) cathode provides a high energy density of 122.7 Wh kg(-1) at a power density of 199 W kg(-1), even a high power density of 10 002.9 W kg(-1) at an energy density of 77.8 Wh kg(-1), and excellent cycle stability (90.4% retention after 10 000 cycles at 1 A g(-1)) in a broad working voltage (0.01-4.0 V), exhibiting the potential of this hybrid materials in lithium storage.